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Top 30 Biology Experiments for High-School

The field of biology offers a wide range of fascinating experiments that can deepen our understanding of the living world around us. From studying the behavior of cells to investigating the intricacies of ecosystems, biologists use a variety of methods to uncover the secrets of life.

We’ve compiled a captivating list of 30 biology experiments that are both educational and fun and also suitable for a wide range of ages.

These hands-on educational activities will not only deepen your appreciation for the intricacies of life but also fuel your curiosity and passion for scientific exploration.

So, roll up your sleeves, gather your lab equipment, and prepare to embark on an exciting adventure through the fascinating world of biology-based science experiments!

1. Grow a Butterfly

Students can gain knowledge about the various phases of development, from the egg to the larva to the pupa to the adult butterfly, by studying and taking care of a butterfly during its whole life cycle. This offers students a special chance to learn about the insect life cycle and the metamorphosis process.

Learn more: Elemental Science

2. Dissecting a Flower

Dissecting a flower can aid students in honing their analytical and observational skills. This may also aid in their comprehension of how a flower’s various components interact to facilitate reproduction, which is the flower’s main objective.

Learn More: How to Dissect a Flower

3. Extracting a DNA

The extraction of DNA is an excellent experiment for high school students to gain a better understanding of the principles of molecular biology and genetics. This experiment  helps students to understand the importance of DNA in research and its applications in various fields, such as medicine, biotechnology, and forensics.

Learn more: Extracting DNA

4. Looking at Fingerprints

Exploring fingerprints can be a fun and intriguing experiment. This experiment encourages students to develop their problem-solving skills and attention to detail, as they must carefully analyze and compare the various fingerprint patterns.

Fingerprint analysis is a fascinating and engaging experiment that can spark an interest in forensic science and provide students with a hands-on learning experience.

Learn more: Directions to Examine a Fingerprint

5. Cultivate Bacteria on Home Made Agar

This experiment provides a hands-on learning experience for students to understand the principles of microbiology and the techniques used in bacterial culture.

This experiment can also help students to understand the importance of bacteria in our daily lives, their role in human health, and their applications in various fields, such as biotechnology and environmental science.  

Learn more: Grow bacteria on Homemade Agar Plates

6. Make a Bioluminescent Lamp

This experiment provides an excellent opportunity for high school students to learn about bioluminescence and the principles of genetic engineering.

Creating a bioluminescent lamp is a fun and engaging way to explore the intersection of biology, chemistry, and physics, making it a perfect experiment for students interested in science and technology.

Learn more: Make Glowing Water

7. Make Plants Move with Light

This experiment can help students understand the role of light in plant growth and photosynthesis and the importance of light as an environmental factor for plant survival. 

Learn more: Experiments with Phototropism

8. Test the Five-Second Rule

The “5-second rule” experiment is a simple and fun way to investigate the validity of the popular belief that it is safe to eat food that has been dropped on the ground for less than 5 seconds.

The experiment is an engaging and informative way to explore the science behind a common belief and promote critical thinking and scientific inquiry among students.

Learn more: Five Second Rule

9. Examine How Antibiotics Affect Bacteria

This experiment is an excellent opportunity for high school students to develop their laboratory skills, such as aseptic technique and bacterial culture, and understand the principles of antibiotic resistance and its implications for human health.

Examining how antibiotics affect bacteria is a fascinating and educational experiment that promotes scientific inquiry and critical thinking among students.

Learn more: Learn About Bacteria

10. Look for Cell Mitosis in an Onion

This experiment is an excellent opportunity for high school students to develop their microscopy skills and understand the biological basis of growth and development in plants. This experiment is a fun and informative way to explore the world of cells and their role in the growth and development of living organisms.

Learn more: Onion Root Mitosis

11. Test the Effects of Disinfectants

Testing the effects of disinfectants is an important process in determining their efficacy in killing or reducing the number of microorganisms on a surface or object. Disinfectants can be hazardous if not used correctly, and testing their effects can help students understand how to use them safely.

Students can learn about proper handling techniques and how to interpret safety labels and warning signs.

Learn more: Antiseptic and Disinfectants

12. Microwave Seed Gardening

Microwave seed gardening is a quick and efficient method of germinating seeds, microwave seed gardening can be a useful method for starting seeds, but it should be used with care and in conjunction with other germination methods to ensure the best possible results. 

Learn more: Microwave plant

13. Water Bottle Bacteria Swab

This experiment can be a fun and informative way to learn about the importance of keeping water bottles clean and free from harmful bacteria. It can also be used to compare the cleanliness of different types of water bottles, such as metal, plastic, or glass.

Learn more: Swabbing Water Bottles

14. Frog Dissection

Frog dissection can be a valuable tool for teaching anatomy and physiology to high school students, as it provides a comprehensive examination of the internal organs and systems of the frog.

Dissection can be a valuable and engaging experiment for high school students interested in biology and life science.

Learn more: Frog Dissection

15. Witness the Carbon Cycle in Action

By witnessing the carbon cycle in action, learners can gain a better understanding of the interconnectedness of different parts of the Earth’s system and the impact that human activities can have on these processes.

Learn more: Carbon Cycle Lab

16. Investigate the Efficacy of Types of Fertilizer

Investigating the efficacy of different types of fertilizer can be an interesting and informative way to learn about plant growth and nutrition. Investigating the efficacy of different types of fertilizer is a practical and engaging way to learn about plant nutrition and the role of fertilizers in agriculture.

Learn more: Best Fertilizer

17. Explore the Impact of Genetic Modification on Seeds

Exploring the impact of genetic modification on seeds is a fascinating and relevant topic that can spark meaningful discussions and encourage learners to think critically about the role of science and technology in society.

Learn more: Genetically Modified (GM) Crops

18. Yeast Experiment

Another easy to perform experiment for high school students is the yeast. This experiment is simple since all that is required is the removal of four different food samples onto separate plates and a thorough examination of the mold that develops on each sample over time.

Learn more: Grow Yeast Experiment

19. Taste Perception 

The human tongue has specialized taste receptors that respond to five primary tastes: sweet, salty, sour, bitter, and umami (savory). Taste perception plays an important role in determining food preferences and dietary habits, as well as influencing the overall eating experience.

Learn more: Taste perception

20. Pea Plant Genetics

A classic pea plant genetics experiment involves cross breeding pea plants with different traits, such as flower color, seed shape, or pod shape.

This experiment can be conducted in a controlled environment, such as a greenhouse, by manually transferring pollen from one plant to another.

Learn more: Gregor Mendel Pea Experiment

21. Comparing Animal and Plant Cells

Comparing animal and plant cells is an important exercise in biology education. Both animal and plant cells are eukaryotic cells, meaning they contain a nucleus and other membrane-bound organelles.

This exercise can help students understand the structure and function of cells, as well as appreciate the diversity of life on Earth.

Learn more: Comparing Plant Cell and Animal Cell

22.  Testing Bacteria 

Bacteria are easily accessible and can be grown in a laboratory or even at home with simple equipment and materials. This makes it a practical and cost-effective experiment for schools with limited resources.

Learn more: How to grow Bacteria and more

23. The Effect of Light on Growth

Light is a fundamental environmental factor that plays a crucial role in the growth and development of plants. By conducting this experiment, students can gain a deeper understanding of how light affects plant growth and why it is important.

Learn more: The effect of light in Plant Growth

24. Planaria Regeneration

Planaria regeneration allows students to design their own experiments, as they can choose which body parts to remove and study the effects of different variables, such as temperature, pH, or chemical treatments on the regeneration process.

Planaria are easy to obtain and maintain in a laboratory or classroom setting. They are also affordable, making it an ideal experiment for schools with limited resources.

Learn more: Planaria Experiment

25. Making a Seed Board

Making a seed board can be a fun and engaging activity for students, as they can see the progress of their plants over time and share their results with others. It can also foster a sense of responsibility and ownership in caring for their plants.

26. Design an Owl Pellet

Dissecting an owl pellet provides a hands-on learning experience for students, allowing them to practice skills in scientific observation, data collection, and analysis. Students can also learn about the anatomy of the prey species found in the owl pellet.

27. Grow an Herbal Cutting

Growing an herb cutting provides a hands-on learning experience for students, allowing them to practice skills in plant care, experimental design, and data collection. Students can learn about the different stages of plant growth and the factors that affect it.

28. Eat a Cell Model

Creating an edible cell model connects to various disciplines, such as biology, anatomy, and nutrition. Students can learn about the different organelles that make up a cell and their functions, as well as the nutritional value of the food materials used in the model

29. Make a Habitat Diorama

Making a habitat diorama provides a hands-on learning experience for students, allowing them to practice skills in research, creative design, and presentation. Students can learn about different ecosystems and the organisms that inhabit them.

30. Create a Fall Leaf (or Signs of Spring) Journal

Creating a fall leaf (or signs of spring) journal provides a hands-on learning experience for students, allowing them to practice skills in observation, data collection, and analysis. Students can learn about the changes that occur in nature during the fall or spring season.

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• 68 Best Chemistry Experiments: Learn About Chemical Reactions
• Top 100 Fine Motor Skills Activities for Toddlers and Preschoolers
• Top 58 Creative Art Activities for Kids and Preschoolers

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Microbe Notes

DNA Experiments (Griffith & Avery, McCarty, MacLeod & Hershey, Chase)

DNA, deoxyribonucleic acid, is the carrier of all genetic information. It codes genetic information passed on from one generation to another and determines individual attributes like eye color, facial features, etc. Although DNA was first isolated in 1869 by a Swiss scientist, Friedrich Miescher, from nuclei of pus-rich white blood cells (which he called nuclein ), its role in the inheritance of traits wasn’t realized until 1943. Miescher thought that the nuclein, which was slightly acidic and contained a high percentage of phosphorus, lacked the variability to account for its hereditary significance for diversity among organisms. Most of the scientists of his period were convinced by the idea that proteins could be promising candidates for heredity as they were abundant, diverse, and complex molecules, while DNA was supposed to be a boring, repetitive polymer. This notion was put forward as the scientists were aware that genetic information was contained within organic molecules.

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Griffith’s Transformation Experiment

In 1928, a young scientist Frederick Griffith discovered the transforming principle. In 1918, millions of people were killed by the terrible Spanish influenza epidemic, and pneumococcal infections were a common cause of death among influenza-infected patients. This triggered him to study the bacteria Streptococcus pneumoniae and work on designing a vaccine against it . It became evident that bacterial pneumonia was caused by multiple strains of S. pneumoniae, and patients developed antibodies against the particular strain with which they were infected. Hence, serum samples and bacterial isolates used in experiments helped to identify DNA as the hereditary material. 

He used two related strains of S. pneumoniae and mice and conducted a series of experiments using them. 

• When type II R-strain bacteria were grown on a culture plate, they produced rough colonies. They were non-virulent as they lacked an outer polysaccharide coat. Thus, when RII strain bacteria were injected into a mouse, they did not cause any disease and survived.
• When type I S-strain bacteria were grown on a culture plate, they produced smooth, glistening, and white colonies. The smooth appearance was apparent due to a polysaccharide coat around them that provided resistance to the host’s immune system. It was virulent and thus, when injected into a mouse, resulted in pneumonia and death. 
• In 1929, Griffith experimented by injecting mice with heat-killed SI strain (i.e., SI strain bacteria exposed to high temperature ensuing their death). But, this failed to harm the mice, and they survived.
• Surprisingly, when he mixed heat-treated SI cells with live RII cells and injected the mixture into the mice, the mice died because of pneumonia. Additionally, when he collected a blood sample from the dead mouse, he found that sample to contain live S-strain bacteria.

Conclusion of Griffith’s Transformation Experiment

Based on the above results, he inferred that something must have been transferred from the heat-treated S strain into non-virulent R strain bacteria that transformed them into smooth coated and virulent bacteria. Thus, the material was referred to as the transforming principle.

Following this, he continued with his research through the 1930s, although he couldn’t make much progress. In 1941, he was hit by a German bomb, and he died.

Avery, McCarty, and MacLeod Experiment

During World War II, in 1943, Oswald Avery, Maclyn McCarty, and Colin MacLeod working at Rockefeller University in New York, dedicated themselves to continuing the work of Griffith in order to determine the biochemical nature of Griffith’s transforming principle in an in vitro system. They used the phenotype of S. pneumoniae cells expressed on blood agar in order to figure out whether transformation had taken place or not, rather than working with mice. The transforming principle was partially purified from the cell extract (i.e., cell-free extract of heat-killed type III S cells) to determine which macromolecule of S cell transformed type II R-strain into the type III S-strain. They demonstrated DNA to be that particular transforming principle.

• Initially, type III S cells were heat-killed, and lipids and carbohydrates were removed from the solution.
• Secondly, they treated heat-killed S cells with digestive enzymes such as RNases and proteases to degrade RNA and proteins. Subsequently, they also treated it with DNases to digest DNA, each added separately in different tubes.
• Eventually, they introduced living type IIR cells mixed with heat-killed IIIS cells onto the culture medium containing antibodies for IIR cells. Antibodies for IIR cells were used to inactivate some IIR cells such that their number doesn’t exceed the count of IIIS cells. that help to provide the distinct phenotypic differences in culture media that contained transformed S strain bacteria.

Observation of Avery, McCarty, and MacLeod Experiment

The culture treated with DNase did not yield transformed type III S strain bacteria which indicated that DNA was the hereditary material responsible for transformation. 

Conclusion of Avery, McCarty, and MacLeod Experiment

DNA was found to be the genetic material that was being transferred between cells, not proteins.

Hershey and Chase Experiment

Although Avery and his fellows found that DNA was the hereditary material, the scientists were reluctant to accept the finding. But, not that long afterward, eight years after in 1952, Alfred Hershey and Martha Chase concluded that DNA is the genetic material. Their experimental tool was bacteriophages-viruses that attack bacteria which specifically involved the infection of Escherichia coli with T2 bacteriophage.

T2 virus depends on the host body for its reproduction process. When they find bacteria as a host cell, they adhere to its surface and inject its genetic material into the bacteria. The injected hereditary material hijacks the host’s machinery such that a large number of viral particles are released from them. T2 phage consists of only proteins (on the outer protein coat) and DNA (core) that could be potential genetic material to instruct E. coli to develop its progeny. They experimented to determine whether protein or DNA from the virus entered into the bacteria.

• Bacteriophage was allowed to grow on two of the medium: one containing a radioactive isotope of phosphorus( 32 P) and the other containing a radioactive isotope of sulfur ( 35 S).
• Phages grown on radioactive phosphorus( 32 P) contained radioactive P labeled DNA (not radioactive protein) as DNA contains phosphorus but not sulfur.
• Similarly, the viruses grown in the medium containing radioactive sulfur ( 35 S) contained radioactive 35 S labeled protein (but not radioactive DNA) because sulfur is found in many proteins but is absent from DNA.
• E. coli were introduced to be infected by the radioactive phages.
• After the progression of infection, the blender was used to remove the remains of phage and phage parts from the outside of the bacteria, followed by centrifugation in order to separate the bacteria from the phage debris.
• Centrifugation results in the settling down of heavier particles like bacteria in the form of pellet while those light particles such as medium, phage, and phage parts, etc., float near the top of the tube, called supernatant.

Observation of Hershey and Chase Experiment

On measuring radioactivity in the pellet and supernatant in both media, 32 P was found in large amount in the pellet while 35 S in the supernatant that is pellet contained radioactively P labeled infected bacterial cells and supernatant was enriched with radioactively S labeled phage and phage parts.

Conclusion of Hershey and Chase Experiment

Hershey and Chase deduced that it was DNA, not protein which got injected into host cells, and thus, DNA is the hereditary material that is passed from virus to bacteria.

• Fry, M. (2016). Landmark Experiments in Molecular Biology. Academic Press.
• https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_Introductory_Biology_(CK-12)/04%3A_Molecular_Biology/4.02%3A_DNA_the_Genetic_Material
• https://byjus.com/biology/dna-genetic-material/
• https://bio.libretexts.org/Bookshelves/Genetics/Book%3A_Online_Open_Genetics_(Nickle_and_Barrette-Ng)/01%3A_Overview_DNA_and_Genes/1.02%3A_DNA_is_the_Genetic_Material
• https://www.toppr.com/guides/biology/the-molecular-basis-of-inheritance/the-genetic-material/
• https://www.nature.com/scitable/topicpage/discovery-of-dna-as-the-hereditary-material-340/
• https://www.biologydiscussion.com/genetics/dna-as-a-genetic-material-biology/56216
• https://www.nature.com/scitable/topicpage/discovery-of-the-function-of-dna-resulted-6494318/
• https://www.ndsu.edu/pubweb/~mcclean/plsc411/DNA%20replication%20sequencing%20revision%202017.pdf
• https://www.britannica.com/biography/Frederick-Griffith
• https://ib.bioninja.com.au/higher-level/topic-7-nucleic-acids/71-dna-structure-and-replic/dna-experiments.html
• https://biolearnspot.blogspot.com/2017/11/experiments-of-avery-macleod-and.html
• https://www.khanacademy.org/science/biology/dna-as-the-genetic-material/dna-discovery-and-structure/a/classic-experiments-dna-as-the-genetic-material

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The Most Beautiful Experiment: Meselson and Stahl

• Duration: 00:22:08

00:00:19:21 John Cairns said on the telephone in a very excited voice, 00:00:22:24 he had just read Mendel's papers 00:00:27:04 [Imitating Cairns] "and you know they are the most beautiful 00:00:29:22 experiments in Biology." 00:00:32:04 And I gasped and I said, "John, John, you can't say that." 00:00:37:10 You said the Meselson-Stahl experiment 00:00:40:18 was the most beautiful experiment in Biology. 00:00:44:02 [Imitating Cairns] "Oh, did I? 00:00:46:12 Well, I was wrong." 00:00:53:22 Watson and Crick didn't make a discovery. 00:00:56:15 They proposed a model. 00:00:59:05 There are those who believed this model must be true 00:01:01:21 because it was so beautiful. 00:01:04:02 And there were those who believed it must be wrong 00:01:06:18 because biology is complicated. 00:01:09:02 And this model is too simple to be right. 00:01:12:01 Would you say? 00:01:13:05 Exactly, yes, 00:01:14:14 But there was no experimental proof of it. 00:01:17:01 They had a model which made a distinct prediction 00:01:20:18 about how DNA replicates and it needed to be tested. 00:01:24:11 And it's fun to test the hypothesis. 00:01:29:03 We agreed that we were going to work together 00:01:32:08 to figure out whether or not it was right. 00:01:38:23 When Frank and I showed semi-conservative replication, 00:01:43:03 It wasn't just a model, it was something real like that. 00:01:47:08 After our experiment, 00:01:48:18 it was now widely accepted that their model, 00:01:52:06 Watson-Crick model is right. 00:01:54:19 So it became the building block. 00:01:58:00 You might say for all of biology. 00:02:00:00 Yeah. 00:02:04:05 From very early childhood, I mean, practically infancy. 00:02:07:21 I loved science. 00:02:08:22 I loved to put wires together to make little radios, 00:02:13:24 which I could put under my pillow. 00:02:15:11 So my parents wouldn't know that I was listening 00:02:17:24 to them all night long. 00:02:19:21 And then I was very interested to know what makes life work. 00:02:24:08 And there had been, I think, in the house, 00:02:29:22 maybe even in my bedroom, that painting by Michelangelo, 00:02:36:02 God up high and Adam below and they're touching fingers. 00:02:42:11 I don't know if there is a spark. 00:02:45:08 I don't think there's a spark in the picture, 00:02:47:04 but I'm not sure. 00:02:48:15 But to me that meant that life is somehow electrical. 00:02:53:10 God is providing life through a spark. 00:02:57:14 And for some reason that made me interested in 00:02:59:12 electrochemistry. 00:03:01:19 Unlike Matthew, 00:03:02:20 I had no particularly strong interest in science as a youth. 00:03:09:11 What was understood that when I graduated from high school, 00:03:14:02 I would apply to the Naval Academy. 00:03:17:01 That's what my mother had in mind because she thought 00:03:19:09 I would look good in dress whites. 00:03:22:08 But then of course, World War II broke out. 00:03:25:01 So that plan changed fast and she decided 00:03:28:13 I should just go to college. 00:03:30:19 I think I was just too young to understand 00:03:33:13 the courses in humanities. 00:03:35:03 I hadn't had enough life experience to get a grip 00:03:38:23 on the questions they were even thinking about. 00:03:41:23 Science on the other hand was concrete. 00:03:44:17 Children can grasp science and among the sciences, 00:03:50:05 biology was the most appealing. 00:03:52:09 There, the fun was that you could figure out puzzles. 00:03:56:24 That is, there was a rational, concrete, 00:03:59:09 quantitative explanation for what you saw. 00:04:03:03 You could reason backwards as to what must be going on. 00:04:07:10 And that intrigued me enough to know that genetics 00:04:10:14 was something perhaps I could do. 00:04:20:19 I had the great, good luck to become Linus Pauling's 00:04:23:21 last graduate student. 00:04:25:09 His daughter was having a party at their swimming pool 00:04:28:12 and I'm in the water. 00:04:29:09 And Pauling comes out, the world's greatest chemist. 00:04:32:16 I'm all naked, practically, in a bathing suit. 00:04:36:13 And he's all dressed up with a jacket and a vest 00:04:40:04 and a neck tie. 00:04:41:11 And he looked down at me, 00:04:42:09 "Well, Matt, what are you gonna do next year?" 00:04:45:00 And I had already signed up 00:04:46:02 to go to the committee on mathematical biophysics 00:04:52:02 and Linus just looked down at me and he said, 00:04:54:00 "But Matt, that's a lot of baloney. 00:04:56:04 Come be my graduate student." 00:04:58:13 And so if I hadn't taken his course 00:05:00:19 on the nature of the chemical bond, 00:05:03:01 I would have had a very different life. 00:05:04:14 I wouldn't have met Frank, 00:05:06:19 I wouldn't be sitting here, that's for sure. 00:05:10:02 At the end of my PhD exam, 00:05:12:12 as we were walking out of the little exam room, 00:05:14:10 Linus Pauling turned to me and he said, 00:05:16:03 "Matt, you're very lucky you're entering this field 00:05:18:13 just at the right moment." 00:05:19:19 Yeah. 00:05:20:15 At the very beginning. 00:05:22:20 (upbeat music) 00:05:28:13 The first year of my being a graduate student at Caltech, 00:05:31:19 I wanted to get into biology. 00:05:33:17 I was a chemist and I thought the way to do that 00:05:36:12 would be to study molecular structure. 00:05:39:16 The only person who was looking at biology 00:05:42:01 from that point of view, other than Linus Pauling himself 00:05:45:10 was Max Delbruck. 00:05:47:03 He had a fearsome reputation. 00:05:49:13 Nevertheless, I got up my courage and went to see him. 00:05:52:10 He's not a fearsome creature at all really. 00:05:54:11 And the first thing he said was, 00:05:56:15 what do you think about these two papers 00:05:58:12 from Watson and Crick? 00:06:00:11 I said, I'd never heard of them. 00:06:03:01 I was still in the dark ages, 00:06:05:22 and he yelled at me. 00:06:07:08 He said, "Get out 00:06:08:04 and don't come back till you've read them." 00:06:13:12 There were two separate ideas that came together. 00:06:16:07 Crick's idea about how the base pairs linked onto the chains 00:06:21:22 and Jim's idea about how the base pairs were structured. 00:06:26:16 So there are four different building blocks in DNA, 00:06:29:07 adenine, thymine, guanine, and cytosine. 00:06:31:19 The surfaces of the G and the C are complementary 00:06:35:13 to each other and of the A and T are complementary 00:06:39:08 to each other so that they can fit together. 00:06:43:05 The way fingers would fit into a glove. 00:06:46:04 And importantly, when they put G opposite C, 00:06:50:21 the distance of the outside was exactly the same 00:06:55:07 as if they'd put A opposite T. 00:06:58:09 No other combination would give such a regular structure. 00:07:02:03 It was a gorgeous insight. 00:07:05:21 And then from that, 00:07:07:01 they made a hypothesis about how DNA is replicated. 00:07:11:02 It involved the two chains coming apart 00:07:15:12 and each one acting as a template for the synthesis 00:07:20:07 of a new chain on its surface. 00:07:24:12 When it's all done, here we have the two old chains, 00:07:27:24 each one now associated with a brand new chain. 00:07:32:08 What Watson and Crick proposed 00:07:34:07 was enormous stimulus to experimentation. 00:07:37:24 It was irresistibly beautiful. 00:07:39:21 Irresistibly beautiful. 00:07:42:22 Jim Watson was at Caltech the year after 00:07:46:19 he and Francis published their papers. 00:07:49:24 And so I got a chance to talk a lot with Jim then, 00:07:53:12 and that coming summer he was going to go 00:07:56:00 and teach the physiology course at Woods Hole. 00:08:01:16 I was a graduate student at Rochester at the time. 00:08:05:06 My chairman of the department who was also on my committee, 00:08:09:05 said I had to take a course in physiology. 00:08:12:18 And I said, the physiologist teacher here is a jerk. 00:08:15:13 I'll be damned if I'll take his course. 00:08:17:19 Well, send him to Woods Hole 00:08:19:23 to take the physiology course there. 00:08:22:16 And by serendipity, Jim Watson happened to be there 00:08:25:19 with some kid named Meselson hanging along with him. 00:08:29:19 We found that we had in fact deep, common interests. 00:08:33:22 I realized this is a guy who's really very smart 00:08:36:18 and I can learn a lot from him. 00:08:38:15 I remember a haze of beach parties, 00:08:42:03 lectures that I slept through 00:08:45:08 Well it was a kind of paradise. 00:08:48:04 The most interesting people in molecular biology. 00:08:51:08 Most of them were there. 00:08:52:22 So that's how we met. 00:08:54:10 And then it turns out Frank is coming that very September 00:08:57:07 to Caltech. 00:08:58:14 It would be a year from then I would come. 00:09:00:06 Are you sure? 00:09:01:03 Yep. 00:09:02:07 I still hadn't finished my thesis- 00:09:03:03 So I had to wait for a whole year before I saw you again? 00:09:05:18 That's right. 00:09:06:14 He said, when you get to Caltech we'll test Jim's idea. 00:09:11:13 What do you think about testing Jim's idea 00:09:13:22 of how DNA replicates? 00:09:15:19 And then he explained that to me, 00:09:17:21 I'd already heard about it and he explained it to me 00:09:20:23 and I absolutely - I committed, totally. 00:09:24:11 And then when Frank finally got there 00:09:26:22 and I wanted to start right away, he forbade it. 00:09:30:17 Why? 00:09:31:14 He said it would be bad for my character 00:09:34:06 to not complete my x-ray crystallography 00:09:37:09 before starting something new. 00:09:40:17 This tells you a lot about Frank's character. 00:09:46:18 With the Watson and Crick model, 00:09:48:16 the underlying question of course was, 00:09:50:23 was that really the right mechanism? 00:09:53:00 The famous Max Delbruck said no, no, no, no, 00:09:56:19 that model can't be right. 00:09:57:19 And he proposed a different model. 00:10:00:03 As Delbruck put it forth, 00:10:02:01 breaks are introduced in the parental molecule 00:10:05:14 as it's being replicated 00:10:07:13 and then carefully sealed up in certain ways. 00:10:10:16 Others proposed one in which 00:10:12:12 the original DNA molecule stays intact. 00:10:16:01 And the new DNA molecule is made of all new DNA. 00:10:21:14 So there were three targets out there 00:10:24:18 that in principle could be distinguished, 00:10:27:00 if you could trace the fate of the old chains, 00:10:30:11 what becomes of the two old chains. 00:10:32:16 And one step led to the next, really. 00:10:35:09 I mean, the first idea was using density somehow, 00:10:39:10 which is not a very good idea yet, 00:10:41:07 except it leads you to the next one. 00:10:43:03 Matt's idea from the very beginning 00:10:45:10 was that somehow stable isotopes could be used. 00:10:50:01 That would be incorporated into the DNA 00:10:53:02 and impart upon the DNA, a different density. 00:10:56:10 You grow bacteria in a medium, 00:10:59:03 which instead of having this ordinary isotope of nitrogen 00:11:03:11 N14, you can buy nitrogen 15 ammonium chloride, 00:11:09:24 the heavy kind. 00:11:12:11 And if you grow the bacteria for a number of generations, 00:11:15:13 you can be sure that essentially all of the DNA 00:11:19:12 is labeled with heavy nitrogen, good. 00:11:23:08 Now, we resuspend those cells in a medium that just has 00:11:26:13 ordinary, nitrogen 14, the light one. 00:11:30:12 And now the question is as the DNA molecules replicate, 00:11:34:23 how will the heavy nitrogen from those parent molecules 00:11:39:04 be distributed amongst the daughter molecules 00:11:42:19 that are produced in successive duplications? 00:11:46:13 Then some sensitive method for separating DNA, 00:11:50:24 according to its density would be devised. 00:11:54:18 I ran across an article about the centrifugation 00:11:58:06 of cesium chloride solution 00:11:59:24 to measure the molecular weight. 00:12:02:01 If the DNA was in there with the cesium, 00:12:05:17 it would find its position in the density gradient. 00:12:09:07 If it was heavy DNA, 00:12:11:15 it would tend to be down near the bottom of the tube 00:12:14:02 where the cesium was concentrated and the density was high. 00:12:18:14 If the DNA was light DNA, made of light isotopes, 00:12:22:18 it would be higher up in the tube. 00:12:29:00 You could think about it this way. 00:12:30:21 If you jumped into the Great Salt Lake, 00:12:32:21 as we all know you float, 00:12:34:15 you go right to the top because you are less dense 00:12:38:00 than the water. 00:12:38:21 But if you have a bathing suit with pockets in it, 00:12:41:10 and you stuffed some lead weights in your pockets, 00:12:44:22 you'll sink down. 00:12:46:05 Cause you're more dense than the water. 00:12:48:22 Now imagine that the salt in the Great Salt Lake 00:12:51:22 is not uniformly distributed, 00:12:54:09 but is concentrated near the bottom 00:12:57:12 and rather less concentrated near the top. 00:13:01:12 Now, if you put just the right number of heavy weights 00:13:04:13 in your pocket, you won't float because you'll be too dense. 00:13:09:05 You won't float at the top and you won't go all the way 00:13:11:13 to the bottom because you're not dense enough. 00:13:14:03 You'll instead come to rest somewhere, 00:13:16:13 halfway between the top and the bottom, 00:13:19:01 you will have found your place in that gradient. 00:13:23:17 And that's the very basis by which the experiment 00:13:26:12 finally worked and worked so beautifully. 00:13:29:01 And then it was just a question of looking 00:13:30:22 in the centrifuge while it's running. 00:13:33:24 And when it reaches equilibrium to see where 00:13:37:07 the heavy and light DNA are. 00:13:39:02 All the makings were there, 00:13:40:13 then to do the experiment itself, 00:13:42:21 it was obvious that the experiment was going 00:13:45:08 to give an answer. 00:13:46:23 Driving it all was the fact that Frank 00:13:49:14 wanted to know how life works. 00:13:57:12 Yeah, yeah. 00:14:01:14 [Mumbles] 00:14:04:09 I don't know that drove it all but- 00:14:07:14 Each person is trying to come up with something 00:14:09:21 as a gift to the other guy. 00:14:12:02 That's true. 00:14:12:23 I think 00:14:13:19 That's true 00:14:14:15 So it becomes a very connected 00:14:17:02 relationship because the next day you want 00:14:20:12 to have something to offer. 00:14:23:09 Matt was ready to step out into an area, 00:14:26:22 pretty heavily uncharted, 00:14:29:23 to answer an important question. 00:14:32:08 And the pieces had to be built as he went along. 00:14:36:15 (upbeat music) 00:14:40:18 The prediction of the Watson and Crick model, 00:14:43:04 was the two parent chains come apart. 00:14:45:00 Each one makes a new daughter molecule 00:14:47:01 and that's replication. 00:14:48:16 So that would predict that after exactly one generation, 00:14:52:16 when everything has doubled in the bacterial culture, 00:14:56:02 that you'd find the DNA molecules all have one old strand, 00:15:01:12 which is labeled heavy. 00:15:03:01 And one new strand, 00:15:05:01 which is labeled light and therefore their density 00:15:08:01 should be halfway between fully heavy and fully light, 00:15:12:06 that would be the prediction for what you see 00:15:15:07 at exactly one generation. 00:15:17:08 What do you predict to see for the next generation? 00:15:20:17 Well, each molecule would, again, separate its chains. 00:15:24:08 One of which is heavy. 00:15:26:00 The other of which is light and the only 00:15:28:14 growth medium available is light growth medium. 00:15:32:08 Then the light chain would make another light chain 00:15:35:04 to go with it, a complement. 00:15:37:05 The heavy chain would make another, 00:15:39:15 a light chain to go with it. 00:15:42:00 So after two generations you have DNA, 00:15:45:11 half of which is half heavy. 00:15:47:13 And the other half of which is all light 00:15:53:13 And fantastically, 00:15:55:05 that's exactly the result that one could see. 00:16:02:24 In order to say that the Watson-Crick model 00:16:06:08 fits the data very well, but the other two models do not, 00:16:10:14 we have to see what they'd predict. 00:16:12:23 Start with the Dispersive Model. 00:16:15:10 After one generation, 00:16:17:02 the two molecules resulting would indeed be half heavy, 00:16:21:10 but in the next generation, 00:16:23:10 there would be a subsequent dispersion of the label. 00:16:26:18 So you'd be getting molecules that were 00:16:29:20 three quarters light, and one quarter heavy. 00:16:34:22 And in each generation, 00:16:36:10 the molecules would get lighter and lighter. 00:16:39:16 The fully Conservative Model simply imagined that duplex DNA 00:16:44:16 fully heavy now, somehow created the appearance of a fully 00:16:51:09 light duplex molecule in which both chains 00:16:54:07 are made of light DNA. 00:16:59:15 Most of the times when you get an experimental result, 00:17:03:19 it doesn't speak to you with such clarity. 00:17:07:19 These pictures of the DNA bands interpreted themselves. 00:17:18:14 It felt like a...supernatural. 00:17:21:22 It felt like you were in touch with the gods 00:17:24:10 or something like that. 00:17:25:16 I remember I presented this result that summer 00:17:29:16 early in the summer in France at a phage meeting, 00:17:33:23 complete with the photographs 00:17:36:02 of the density gradient bandings. 00:17:39:05 And at the end of it, 00:17:41:17 I stopped and there was total silence and somebody said, 00:17:45:16 "Well, that's it." 00:17:53:21 The intellectual freedom at Caltech. 00:17:56:02 We could do whatever we wanted. 00:17:58:00 It was very unusual for such young guys 00:18:00:19 to do such an important experiment. 00:18:02:23 So suddenly, whereas before that, 00:18:05:12 like Max would be talking with Sinsheimer 00:18:08:00 about the genetic code. 00:18:09:23 And before we did our experiment, 00:18:11:10 I was definitely not - at least 00:18:13:11 I felt I wasn't - supposed to be at those discussions. 00:18:16:15 But afterwards, I could be a full member. 00:18:20:06 We had this wonderful house, 00:18:21:15 big house across the street from the lab. And our roommates, 00:18:26:19 we all, 00:18:27:15 we talked about these experiments at almost every dinner. 00:18:31:01 So we had this wonderful intellectual atmosphere, 00:18:35:11 John Drake, Howard Temin. 00:18:38:00 Why are you frowning? 00:18:39:06 He told the dirtiest jokes I've ever heard. 00:18:41:04 No that was Roger Milkman. 00:18:42:20 [Crosstalk] 00:18:45:11 Positions one and two. 00:18:46:18 That's true, that's true, that's true. 00:18:49:05 So it was a very lively, intense, friendly atmosphere. 00:18:56:12 It was lively enough and conveniently located enough 00:19:00:12 that over time we had visits from William O. Douglas, 00:19:05:17 Judge Douglas. 00:19:06:13 Judge Douglas of the Supreme Court 00:19:08:11 And here Dick Feynman probably one of the world's greatest 00:19:13:13 physicists at that time, 00:19:15:04 or maybe ever, palled around with us. 00:19:17:17 He came over to our big house and played his drums, 00:19:22:00 sat down on the floor, played the drums. 00:19:24:21 I'm just a graduate student 00:19:26:03 and he's the world's greatest physicist, 00:19:29:17 but that's what it was like. 00:19:30:22 It was a very friendly wide open place. 00:19:33:10 Frank and I are very lucky. 00:19:36:20 The way I think of it is that there's a river, 00:19:39:17 which is a period of time when the fundamental things, 00:19:42:21 the structure of DNA, how replication happens, 00:19:45:10 the genetic code. 00:19:47:06 And then, when these problems are solved. 00:19:50:22 There are lots of little rivulets. 00:19:51:18 The river divides into thousands of branches 00:19:55:16 using these fundamental insights into how life works 00:20:00:16 and applying them to specific questions, 00:20:03:14 questions of disease etc. 00:20:07:09 So to me, with some exceptions, 00:20:11:21 this was a really interesting time 00:20:14:00 when it was still a big river. 00:20:16:04 Also, now you can cut this out, 00:20:19:04 but also the Meselsons, Matt's parents, were kind enough to 00:20:22:14 keep the liquor cabinet fully stocked at all times. 00:20:29:22 (upbeat music) 00:20:49:15 My throat is a little bit? 00:20:51:22 I have a cough drop 00:20:54:06 (whispering) I don't want a cough drop. I want a non-alcoholic beer. 00:20:58:21 I require a margarita. 00:21:00:22 I've worked for the CIA. 00:21:04:08 I vaporized many people, including many of your friends, 00:21:08:16 Big black beard, 00:21:09:19 and blew out some of his pipe smoke and still 00:21:12:20 holding his pipe stem in his teeth said, 00:21:15:01 "Oh Matt history is just what people think it was."

• General Public
• Educators of H. School / Intro Undergrad

Talk Overview

Matt Meselson and Frank Stahl were in their mid-20s when they performed what is now recognized as one of the most beautiful experiments in modern biology. In this short film, Matt and Frank share how they devised the groundbreaking experiment that proved semiconservative DNA replication, what it was like to see the results for the first time, and how it felt to be at the forefront of molecular biology research in the 1950s. This film celebrates a lifelong friendship, a shared love of science, and the serendipity that can lead to foundational discoveries about the living world.

Please head to the Science Communication Lab’s website for more films like this along with educator resources, full video transcript, and most up to date content.

Speaker Bio

Frank stahl.

Frank Stahl received his PhD at the University of Rochester, where he studied genetic recombination in phage. He performed postdoctoral studies at Caltech, during which he completed the famous Meselson-Stahl experiment, and joined the faculty at the University of Oregon in Eugene in 1959. He is now an emeritus faculty member who enjoys teaching and… Continue Reading

Matthew Meselson

Dr. Meselson has made important contributions to the areas of DNA replication, repair and recombination as well as isolating the first restriction enzyme. Currently, he is Professor of Molecular and Cellular Biology at Harvard University, where his lab studies aging in the model organism bdelloid rotifers. Meselson is also a long-time advocate for the abolition… Continue Reading

More Talks in Genetics and Gene Regulation

Related Resources

Meselson M. and Stahl F. The replication of DNA in Escherichia coli . PNAS July 15, 1958 44 (7) 671-682.

Teaching resources from XBio: How DNA Replicates

Sarah Goodwin (Wonder Collaborative): Executive Producer Elliot Kirschner (Wonder Collaborative): Executive Producer Shannon Behrman (iBiology): Executive Producer Brittany Anderton (iBiology): Producer Derek Reich (ZooPrax Productions): Videographer Eric Kornblum (iBiology): Videographer Rebecca Ellsworth (The Edit Center): Editor Adam Bolt (The Edit Center): Editor Gb Kim (Explorer’s Guide to Biology): Illustrations Chris George: Design and Graphics Maggie Hubbard: Design and Graphics Marcus Bagala: Original music Samuel Bagala: Original music

Reader Interactions

ANGELA DIXON says

February 8, 2021 at 9:39 pm

Thank you – I cannot tell you how much I enjoyed this video. It was as if I was sitting in Dr. Stahl’s living room, having a conversation with these two great scientists. What an elegant experiment! You have really captured the essence of two incredible scientists in this video.

Marieke Mackintosh says

March 23, 2021 at 12:08 pm

Thank you for sharing this incredible footage of these brilliant human beings. What a joy it is to watch them reminisce and teach. I cannot wait to show this to my students.

Neeraja Sankaran says

August 30, 2022 at 7:00 am

Hi.. this is not a comment except to say that this is a beautiful video. Could you give me the full citation please, I’d like to include it in a bibliography

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10 High School Science Lab Experiments - Biology

At its core, biology aims to answer fundamental questions about the nature of life, such as how organisms are composed, how they function and maintain homeostasis, how they grow and reproduce, how they evolve and adapt to their environment, and how they interact with one another and their surroundings. 

High school biologyteachers have so many in-person and virtual lab options for high school lab experiments. We’ve broken them down into five categories:

DNA Experiments

Microscopy experiments, osmosis & diffusion experiments, bacteria experiments , genetics experiments, in-person lab: extracting dna from strawberries.

This activity teaches students about the structure and function of DNA while also demonstrating how DNA can be isolated from cells. Students crush strawberries and use a lysis buffer to break down cell and nuclear membranes, releasing the DNA. The mixture is then filtered, and rubbing alcohol is added to precipitate the DNA, making it visible as a cloudy, stringy substance.

Virtual lab: DNA: Structure and Function

In the narrative of this virtual lab, students will work as an intern for a science magazine, Science Explained. One of the magazine’s readers has written a letter. They’re confused about DNA and have some questions about its structure and function. It’s their job to find out the answers and clear things up. They’ll get to learn how DNA is structured and how DNA’s code translates to functional molecules called proteins.

In-person experiment: Onion cell microscopy

This teaches students about cell structure and function using onion epidermal cells. Students prepare a wet mount slide with a thin layer of onion cells, stain them with iodine, and observe the cells under a microscope. It allows students to visualize plant cell components, such as the cell wall, cell membrane, and nucleus, while gaining experience with microscopy techniques.

Virtual lab: Meiosis, Mitosis and Plant Gametes 

Students will use microscopy to study samples of lily anthers while helping the team at the laboratory. They’ll study the process of cell division and discover the key differences between meiosis and mitosis. 

In-person lab: Diffusion and osmosis with eggs

Students use decalcified eggs (eggs soaked in vinegar to remove the shell) to study the processes of diffusion and osmosis. By immersing the eggs in various solutions, such as distilled water or corn syrup, students can observe changes in mass and size due to the movement of water across the semi-permeable membrane of the egg.

Virtual lab: Osmosis and Diffusion: Choose the right solution for an intravenous drip

In this virtual lab, students will help save Frank’s life by choosing the correct saline solution for an intravenous drip. He’s dehydrated because of sunstroke and needs extra fluids. They’ll join our virtual lab assistant in the lab to discover what a hypotonic, isotonic, and hypertonic solution is and how water is transported across the cell membrane in osmosis.

Photosynthesis Experiments

In-person lab: photosynthesis and respiration in plants.

Students use an aquatic plant, such as Elodea, and a dissolved oxygen probe or a simple inverted test tube setup to measure the rate of oxygen production during photosynthesis and consumption during cellular respiration. This experiment helps students understand the complementary processes of photosynthesis and cellular respiration in plants.

Virtual lab: Photosynthesis: Electron transport chain

To understand how photosynthesis works, students will shrink to a tiny size and go inside the plant cell of a leaf. Travel further inside the cell into the chloroplast, and then look at the thylakoid membrane. The process of photosynthesis takes place here. Observe the different components of the electron transport chain, from the start of the chain at photosystem II to the end of the chain at ATP synthase. 

In-person experiment: Bacterial growth and antibiotic resistance

Students culture bacteria (e.g., E. coli) on agar plates and test the effectiveness of different antibiotics. They observe zones of inhibition, where bacterial growth is prevented, and learn about antibiotic resistance and the importance of proper antibiotic use.

Virtual lab: Gram Stain: How stains and counterstains work

Dive into the microscopic world and discover the colorful magic of the Gram staining procedure! Students will compare and contrast the cell wall of Gram-positive and Gram-negative bacteria by diving into their microscopic samples and observing how the cell wall structures retain certain reagents during the experiment. Discover how the four reagents of the Gram stain interact with structural components of the cell wall to color the bacteria.       

In-person experiment: Monohybrid Cross and Mendelian Genetics

Students observe the results of monohybrid crosses involving a single trait. Using Punnett squares, students predict offspring ratios and compare them with observed outcomes from live organisms, such as pea plants or fruit flies. This activity helps students understand inheritance, dominant and recessive alleles, and how traits are passed from one generation to the next.

Virtual lab: Mendelian Inheritance: From genes to traits

Did you know that more than 99% of your genes are identical to those found in any other human being on the planet? In this simulation, students will learn how Mendel's postulates can be applied to determine how characteristics are inherited by being passed from one generation to the next.

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• The Theory of Biogenesis

What is Biogenesis?

An important theory in biology and molecular genetics, Biogenesis postulates the production of new living organisms from pre-existing life. Read ahead as we explore this seminal theory that changed age-old beliefs.

Biogenesis is based on the theory that life can only come from life, and it refers to any process by which a lifeform can give rise to other lifeforms. For instance, a chicken laying eggs, which hatch and become baby chicken.

Meaning of Biogenesis

The term ‘biogenesis’ comes from ‘bio’ meaning ‘life’, and ‘ genesis’, meaning ‘beginning’. Rudolf Virchow, in 1858, had come up with the hypothesis of biogenesis, but could not experimentally prove it. In 1859, Louis Pasteur set up his demonstrative experiments to prove biogenesis right down to a bacterial level. By 1861, he succeeded in establishing biogenesis as a solid theory rather than a controversial hypothesis.

What Was the Idea of Spontaneous Generation?

The belief in a spontaneous generation is age-old, quite literally. Aristotle in Ancient Greece first pronounces the idea. And consequently, the idea also came to be known as Aristotelian Abiogenesis.

The reason behind the resounding faith in this idea was perhaps the elusive and stealthy nature of the creatures attributed to it, i.e, mice, bacteria, flies, maggots, etc.

The 18th-century path-breaking invention of the microscope that allows most of these creatures, so we can observe them under the microscope and de-mystify their origin. By the time Pasteur set about to do his work in the field, macroscopic biogenesis was already accepted by the scientific community at large. He only had to confirm microscopic biogenesis to prove the hypothesis beyond doubt.

Macroscopic Biogenesis: Francesco Redi’s Experiment

Francesco Redi, as far back as 1668, had set out to refute the idea of macroscopic spontaneous generation, by publishing the results of his experimentation on the matter. Instead of his experiment , Redi had placed some rotting meat in two containers, one with a piece of gauze covering the opening, and the other without it.

He noticed that in the container without the gauze, maggots would grow on the meat itself. However, when he provided the gauze, the maggots would appear on the gauze instead of on the meat. He also observed that flies tend to lay eggs as close to a food source as possible. Thus, he surmised the possibility of macroscopic biogenesis.

Microscopic Biogenesis

Spallanzani’s experiment.

Source: Emaze

He solved this problem by drawing out all the air in the container after sealing it. After experimenting with this manner, he achieved his desired results of a broth that had not clouded with bacterial growth, in line with the theory of biogenesis.

However, his inference was countered by critics who asserted that air was indispensable to support life, therefore the lack of bacterial growth should be attributed to the lack of air, rather than the fact that bacteria spread through contamination. For almost a century since this criticism lay unchallenged.

Pasteur’s Experiment   

The caveat of Pasteur’s 1859 experiment was to establish that microbes live suspended in air, and can contaminate food and water, however, the microbes do not simply appear out of thin air. As the primary step to his experiment, Pasteur boiled beef broth in a special flask that had its long neck bent downwards and then upwards.

This interesting contraption ensured the free diffusion of air, and at the same time prevent any bacterial contamination. As long as the apparatus remained upright, the flask remained free of any bacterial growth.

Once we slant the flask, it allows the broth to pass beyond the ‘goose-neck’ bend of the flask’s neck. The broth became clouded with bacterial growth in no time. This path-breaking experiment not only silenced all the criticism based on Spallanzani’s experiment but also cemented the Law of Biogenesis.

Law of Biogenesis Vs. Evolutionary Theory

Scientist fears that the law of biogenesis opposes the theory of evolution. It has surmised that all life stems from inorganic matter from billions of years ago. However, biogenesis simply refutes the theory of spontaneous generation and delves in a matter of generational time-span, and not of what may be achieved over thousands of generations.

While the evolutionary theories take into account the lack of predators, the difference in the chemical composition of the Earth’s atmosphere during the inception of life on Earth, as well as the trial-and-error that had taken place over millions of years to bring us to the stage of life on this planet we witness now, these do not concern the law of biogenesis at all.

Whereas the evolutionary theory demonstrates how life on earth took millions of years of trial-and-error and conducive but very different atmospheric conditions, the theory of spontaneous generation had asserted that complex life could simply appear fully formed in a matter of days. This is the belief that biogenesis had successfully challenged.

Solved Question for You

Q. Who Has Propounded the Theory of Spontaneous Generation?

• Spallanzani

Ans. C. Aristotle. The idea was first propounded by Aristotle in Ancient Greece. Consequently, the idea came to be known as Aristotelian Abiogenesis.

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Molecular Genetics

• What are Genotypes and Phenotypes? – Definition and Examples
• Chromatid – Definition, Parts, and Functions
• Chromosome – Definition, Structure, Function, Examples
• Homozygous – Definition, Characteristics, and Examples
• Chargaff’s Rule – What is Chargaff’s Rule of Base Pairing?
• Genetic Diversity – Definition, Importance, Examples
• Heterozygous – Definition and Characteristics
• Difference Between Homozygous & Heterozygous

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• Prof. Jing-Ke Weng
• Dr. Nelly Cruz

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Experimental molecular genetics, course description.

This project-based laboratory course provides students with in-depth experience in experimental molecular genetics, using modern methods of molecular biology and genetics to conduct original research. The course is geared towards students (including sophomores) who have a strong interest in a future career in …

This project-based laboratory course provides students with in-depth experience in experimental molecular genetics, using modern methods of molecular biology and genetics to conduct original research. The course is geared towards students (including sophomores) who have a strong interest in a future career in biomedical research. This semester will focus on chemical genetics using Caenorhabditis elegans as a model system. Students will gain experience in research rationale and methods, as well as training in the planning, execution, and communication of experimental biology.

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Five Biology Experiments for College You Need to Try in 2022

Students come to college biology classes with a diversity of prior laboratory experiences and a range of practical laboratory skills. Modern Biology assists instructors in bringing every student to an acceptable level of technique with interesting experiments that reinforce scientific methods and meticulous reporting skills.

Here are five biology experiments for college from Modern Biology that you need to try in 2022.

Forming Hypotheses About DNA

The ability to form and test hypotheses is fundamental to mastering the scientific method. Our Modern Biology experiment  B1-1: Properties of DNA , in which students precipitate strands of DNA from solution with alcohol and manipulate them with glass rods, gives students an opportunity to think outside the box.

This experiment is deceptively simple. After all, it’s also a demonstration activity in middle school. But the ability to look at a simple exercise from a scientific perspective sets the tone for future experiments more clearly on the college level. And the simplicity of this experiment makes it an opportunity to get all the students on the same page regarding laboratory procedures and reports.

Introducing Your Students to Electrophoresis

Electrophoresis is a fundamental investigative tool for college biology. And it’s a topic that college students should feel at home with. After all, they submit samples for electrophoretic testing for COVID-19 on a nearly continuous basis.

For college biology classes, electrophoresis is the basic tool for isolating, visualizing, measuring, characterizing, and comparing DNA, RNA, and other large proteins. Students get the basic lab skills for electrophoresis in Modern Biology’s  Experiment O3: An Introduction to Electrophoresis . Even college students may need experience using a pipette and making sure wells are filled equally. They may need reminders about ensuring that reagents are used at the proper pH and temperatures. And because slight errors in technique can lead to large differences in results, students will have to evaluate their technique to interpret their results.

Practical Biology

A collection of experiments that demonstrate biological concepts and processes.

Observing earthworm locomotion

Practical Work for Learning

Published experiments

Inheritance, experiments.

• Introducing ideas about inheritance

10 Amazing Things Scientists Just Did with CRISPR

Crispr technology.

It's like someone has pressed fast-forward on the gene-editing field: A simple tool that scientists can wield to snip and edit DNA is speeding the pace of advancements that could lead to treating and preventing diseases.

Findings are now coming quickly, as researchers can publish the results of their work that's made use of the tool, called CRISPR-Cas9.

The tool, often called CRISPR for short, was first shown to be able to snip DNA in 2011 . It consists of a protein and a cousin of DNA, called RNA. Scientists can use it to cut DNA strands at very precise locations, enabling them to remove mutated parts of genes from a strand of genetic material. 

In the past year alone, dozens of scientific papers from researchers around the world have detailed the results of studies — some promising, some critical — that used CRISPR to snip out and replace unwanted DNA to develop treatments for cancer, HIV, blindness, chronic pain, muscular dystrophy and Huntington's disease, to name a few. 

"The pace of basic research discoveries has exploded, thanks to CRISPR," said biochemist and CRISPR expert Sam Sternberg, the group leader of technology development at at Berkeley, California-based Caribou Biosciences Inc., which is developing CRISPR-based solutions for medicine, agriculture, and biological research.

Although it will be a few more years before any CRISPR-based treatments could be tested in people, "hardly a day goes by without numerous new publications outlining new findings about human health and human genetics that took advantage" of this new tool, Sternberg told Live Science.  

Of course, humans are not the only species with a genome. CRISPR has applications in animals and plants, too, from disabling parasites, like those that cause malaria and Lyme disease, to improving the crop yields of potatoes, citrus and tomatoes. 

"[CRISPR] is incredibly powerful. It has already brought a revolution to the day-to-day life in most laboratories," said molecular biologist Jason Sheltzer, principal investigator at the Sheltzer Lab at Cold Spring Harbor Laboratory in New York. Sheltzer and his team are using CRISPR to understand the biology of chromosomes and how errors associated with them may contribute to cancer.

“I am very hopeful that over the next decade gene editing will transition from being a primarily research tool to something that enables new treatments in the clinic,” said Neville Sanjana, of the New York Genome Center and an assistant professor of biology, neuroscience and physiology at New York University.

Here, we take a look at the recent advances in the fights against 10 diseases that demonstrate CRISPR's capabilities, and hint at things to come. 

A cure for cancer has alluded humankind since the Greek physician Hippocrates, who lived between 460 and 370 B.C., coined the word for this disease: karkinos. But because cancer, like many diseases, results from a mutation in a person's genome, researchers say it's possible that a CRISPR-based treatment could one day slow the speed at which a tumor spreads, or perhaps reverse the disease completely. 

Some early work in this area is happening already in China , where regulations governing the use of gene editing in humans are more relaxed than they are in the United States. 

In October 2016, a lung cancer patient in China became the first of 10 people in the world to receive an injection of cells that had been modified using CRISPR, the journal Nature reported . The researchers, led by oncologist Dr. Lu You at Sichuan University in Chengdu, modified the immune cells taken from the patient's own blood and disabled a gene that produces a protein that cancer cells normally hijack in order to divide and multiply. The hope is that without the protein, the cancer cells won’t multiply and the immune system will win out. 

Research teams in the United States are also eyeing ways to use CRISPR to fight cancer. Dr. Carl June, director of translational research at the Abramson Cancer Center at the University of Pennsylvania, and his colleagues received approval in June 2016 from the National Institutes of Health to conduct a clinical trial on 18 cancer patients in late stages of melanoma (a skin cancer), sarcoma (a cancer of soft tissue) and multiple myeloma (a cancer of the bone marrow), according to a statement from the university. For this clinical trial, researchers will use CRISPR to alter three genes in patients' own immune system cells, in hopes of getting those cells to destroy the cancer cells in their bodies.

Eradicating HIV, the virus that causes AIDS, has been an uphill battle. Not only does the virus infect the very immune cells in the body that attack viruses, but it's also a notorious mutator. After HIV hijacks a cell in the body and begins to replicate, it generates many genetic variations of itself, which helps it evade drug therapies. This drug resistance is a huge problem in treating people who are infected with HIV, according to the World Health Organization.

CRISPR has HIV lined up in its sight, though. In May 2017, researchers at Temple University and the University of Pittsburgh used CRISPR to snip the virus from the cell it was infecting, shutting down the virus's ability to replicate. This use of the technique, which was tested in three different animal models, was the first time researchers had demonstrated a way to eliminate HIV from infected cells, according to the researchers, led by Chen Liang, a virologist at McGill University in Montreal. They reported the results of their study in the journal Molecular Therapy . 

Huntington's disease

About 30,000 people in the United States have an inherited condition called Huntington's disease, a fatal genetic disorder that causes nerves in the brain to deteriorate over time, according to the Huntington's Disease Society of America . Symptoms include personality changes, mood swings, unsteady gait and slurred speech. 

The condition results from a faulty gene that becomes larger than normal and produces a larger-than-normal form of a protein called huntingtin, which then breaks into smaller, toxic fragments that accumulate in neurons, disrupting their function, according to the National Institutes of Health .

But in June 2017, scientists reported in The Journal of Clinical Investigation that they had reversed the disease in lab mice that had been engineered to have a human mutant huntingtin gene in place of a mouse huntingtin gene. Su Yang, a Postdoctoral Fellow in the department of human genetics at Emory University in Atlanta, and Renbao Chang, at the Institute of Genetics and Developmental Biology at the Chinese Academy of Sciences, used CRISPR to snip out part of the mutant huntingtin gene that produces the toxic bits. 

After they did that, the number of toxic fragments decreased in the mice's brains, and the neurons began to heal. The affected mice regained some of their motor control, balance and grip strength. Although their performance on certain tasks was not as good as that of healthy mice, the results showed the potential of CRISPR to help fight this condition. 

In a statement , the scientists stressed that more rigorous studies need to be conducted before such a therapy could be used in humans.

Duchenne muscular dystrophy

Duchenne muscular dystrophy is a debilitating condition that develops because of a mutation in a single gene, called the dystrophin gene, which is one of the longest genes in the body. A team of researchers at the University of Texas Southwestern Medical Center led by molecular biology professor Eric Olson is working with CRISPR to find ways to fight Duchenne muscular dystrophy. 

Because of the mutation in the dystrophin gene, the body doesn't make a functional form of the protein dystrophin, which is essential for muscle fiber health. Over time, the lack of this protein causes progressive muscle degeneration and weakness. 

In April 2017, Olson and his team reported in the journal Science Advances that they had used a variation of the CRISPR tool, called CRISPR-Cpf1, to correct the mutation that causes Duchenne muscular dystrophy. They fixed the gene in human cells growing in lab dishes and in mice carrying the defective gene. 

CRISPR-Cpf1 is another instrument in the gene-editing toolbox. It differs from the more commonly used CRISPR-Cas9 in that it's smaller, thus making it easier to deliver to muscle cells, according to a statement from UT Southwestern Medical Center. It also recognizes a different sequence of DNA than Cas9, which came in handy for editing the very long dystrophin gene. 

Preventing blindness

One of the most common causes of childhood blindness is a condition called Leber congenital amaurosis, which affects about 2 to 3 per 100,000 newborns, according to the National Institutes of Health . The condition is inherited and is caused by mutations in at least 14 genes that are responsible for normal vision. 

The Cambridge, Massachusetts-based biotech company Editas is working on a CRISPR-based therapy to reverse a type of the disease called Leber congenital amaurosis type 10. The company is aiming to file the necessary papers with the Food and Drug Administration by the end of 2017 to start the first human trials on treatments for this condition, the biotech news website Xconomy reported .

Editas was co-founded by Feng Zhang, a bioengineering professor at MIT who demonstrated that CRISPR-Cas9 could be used on human cells. Jennifer Doudna, of the Unversity of California, Berkeley, and Emmanuelle Charpentier, then of the University of Vienna, also demonstrated that CRISPR-Cas9 could snip DNA, and they filed a patent on the technology in 2012. The Broad Institute, which is part of MIT, submitted its patent in April 2014 and fast-tracked it, ultimately getting the patent. The Broad Institute's patent was upheld in February, 2017, after the University of California, Berkeley filed a lawsuit claiming Doudna had been first, Nature reported.

Chronic pain

Chronic pain is not an inherited genetic disease, but scientists are investigating ways to use CRISPR to curb back and joint pain by altering genes to reduce inflammation. Under normal conditions, inflammation is the body's way of telling the immune system to repair tissue. But chronic inflammation can do the opposite and damage tissue, eventually causing debilitating pain.  

In March 2017, a team of researchers led by bioengineering assistant professor Robby Bowles of the University of Utah reported that they had used CRISPR to prevent certain cells from producing molecules that are designed to break down tissue and lead to the inflammation that causes pain, according to a statement from the university .

The technique could be used to delay the degeneration of tissue after back surgery, for example. This could speed healing and reduce the need for additional surgeries to correct tissue damage.

Lyme disease

Kevin Esvelt, an evolutionary biologist at MIT, wants to wipe out Lyme disease, which is caused by a tick-borne bacterium that can spread from deer-tick bites to people. If left untreated, the infection can cause joint inflammation, nerve pain, heart palpitations, facial palsy and other problems, according to the CDC. 

Although the bacteria that cause Lyme disease are transmitted to people by the deer tick, the ticks themselves don't have the bacteria when they hatch from eggs. Rather, young ticks pick up the bacteria when they feed, often on the white-footed mouse. Esvelt wants to reduce the disease by using CRISPR-Cas9 to genetically modify white-footed mice in a way that would make them and their offspring become immune to the bacteria and unable to pass it along to ticks, Wired reported .

In June 2016, Esvelt presented his solution to the residents of the islands of Nantucket and Martha's Vineyard, in Massachusetts, which have a major Lyme disease problem, the Cape Cod Times reported . Such mice will not be released on the island, however, until further testing is done, and that could take years. 

Malaria kills hundreds of thousands of people per year. In 2015, the most recent year for which the World Health Organization has statistics, there were roughly 212 million malaria cases and about 429,000 malaria deaths. 

To attack the problem at the source, research teams at Imperial College London are aiming to reduce the populations of malaria-transmitting mosquitoes. According to a statement from the college, a group of scientists led by professors Austin Burt and Andrea Crisanti will investigate two main courses of action: genetically modifying the male mosquitoes so that they produce more male offspring, and genetically modifying the female insects in a way that lowers their fertility. 

In December 2015, the team reported in the journal Nature that they had identified three genes to reduce female mosquito fertility. They also announced that they had found that CRISPR could work to target at least one of them. 

Just as CRISPR can be used to modify the genomes of humans and animals, it can be used to modify the genomes of plants. Scientists are investigating ways to harness the tool's gene-editing ability to reduce disease in some crops and make others more robust. 

Sophien Kamoun, a professor at the Sainsbury Laboratory in Norwich, England, for example, is looking at ways to remove the genes that make potatoes and wheat vulnerable to disease, PhysOrg reported. Zachary Lippman, a geneticist at Cold Spring Harbor Laboratory in New York, is using CRISPR to develop tomato plants with branches that are optimized to handle the weight of ripe tomatoes and not break, Nature reported. And in California, several labs are trying to harness CRISPR to tackle a plant disease called citrus greening , which is caused by bacteria that spread by insects that fly among plants in a citrus grove, Nature News reported.

Editing a viable human embryo

The speed with which CRISPR-based studies can go from hypothesis to result is astounding. Experiments that used to take months now take weeks, Sheltzer told Live Science. That speed has raised some concerns from policymakers and stakeholders, especially when it comes to using such a technology on humans. 

In February 2017, scientists at The National Academies of Sciences, Engineering and Medicine issued an assessment of human gene editing, saying that it was acceptable but only under certain conditions. The group also said that altering the cells in embryos, eggs and sperm was ethically permissible provided that it was done to correct a disease or a disability, not to enhance a person's physical appearance or abilities, Science News reported .

Although no scientists in the United States have used CRISPR to modify a viable human embryo yet, a team led by Jianqiao Liu of Guangzhou Medical University in China reported such an advance March 1, 2017, in the journal Molecular Genetics and Genomics . The scientists used CRISPR-Cas9 to introduce and then edit out disease-causing mutations from human embryos. The study was done to show that the genetic editing could be done at the embryonic stage. The embryos were not implanted in a human. 

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Q&A with genetics and cell biology student Sam Kindl

When he isn’t summiting the tallest peaks in the Pacific Northwest, Sam Kindl is working toward earning a degree in genetics and cell biology in the School of Molecular Biosciences , with minors in math and computer science. When the Spokane native wraps up his undergraduate studies in the College of Veterinary Medicine , he plans pursue a doctorate degree.

What initially drew you to your major?

I started in bioengineering my freshman year but after my research experience in Dr. Ryan Driskell’s lab , I wanted to take classes that could help accelerate my research and broaden my knowledge in genetics.

Who has been the most influential mentor or professor during your time at WSU, and how have they impacted you?

Dr. Ryan Driskell has been the most influential mentor I’ve ever had. Over the three years I’ve worked in his lab he’s given me opportunities to pursue independent projects mentoring me through them. Because of his help and encouragement, I’m currently working on a first-author manuscript that I hope to publish in the spring.

Have you had any opportunities to work in a lab or conduct research while at WSU? How has that experience impacted your studies?

My research experience has been a central part of my education, giving me the freedom to explore what I find interesting. This has greatly expanded my understanding of specific areas of biology and what the research process looks like. I feel confident transitioning to graduate-level research after I graduate and start my PhD.

What advice would you give to someone thinking about majoring in a field within the College of Veterinary Medicine?

I may be biased but I would say to join a lab as early as possible, many professors prefer to let a freshman/sophomore join their lab as they can be trained and potentially work for years over a junior/senior who will graduate soon. Depending on what you want to do after your bachelor’s degree, research experience is irreplaceable in gaining knowledge and technical ability.

What’s your favorite thing about WSU?

I would say the sense of community found within our major and labs. I enjoy hanging out with other students in the Biotechnology Life Sciences Building between work and classes.

What are your post-graduation plans, and how do you see your education at WSU helping you achieve them?

I’m going to pursue a PhD with a focus in tissue regeneration with a long-term goal of becoming a principal investigator and running my own lab. By interacting with the graduate students and professors here at WSU, I have a better understanding of how to accomplish my goals.

What hobbies or extracurricular activities have you enjoyed at WSU, and how have they enriched your time here?

I enjoy cycling on roads out on the Palouse. Pullman is nice because whenever I feel overwhelmed by class or work, I can escape out onto the empty roads surrounded by beautiful scenery.

What’s a fun or surprising fact about you that most people wouldn’t guess?

Something interesting I would say is my interest in mountaineering, Last summer I climbed Mt. Hood and Mt. Adams, and next year I hope to climb Mt. Rannier and Mt. Baker.