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Course: Middle school biology - NGSS > Unit 7
Lesson 2: Genes, proteins, and traitsGenes, proteins, and traits
Genes are specific stretches of nucleotides on a DNA molecule. Genes encode proteins, which are made up of amino acids. The order of nucleotides in a gene determines the order of amino acids in a protein. A protein’s amino acids determine its 3D shape and its functions in the cell, which, in turn, affect an organism’s traits. Created by Khan Academy.
Want to join the conversation?
- What if we found a way to get the 'fluorescent' gene (2:24) into humans? Would we start glowing?(17 votes)
- Unfortunately, GFP has more than one function. Other than being a cool glowing green thing, it also causes your cells to self destruct.
I don't think most people would like to have a section in your DNA that codes for a protein that causes your cells to die.
An alternative, wearable LED strips,
- are more visible (Example: Christmas lights)
- are cheaper (gene editing is more expensive)
- are reversible (you can take it off or turn it off at any time)
- are customizable (You can make different arrangements and stuff)
- are programmable (Rainbow "skin" or something else)
- do not result in the user's demise(24 votes)
- If you combine a spiders DNA with human DNA will you get Spider-man or agiant mutated spider?(10 votes)
- This is quite a funny question. I have seen other questions like this, but about whether or not plant cells and animals cells have ever worked together in an organism before. I'm not quite sure about the answer, but I don't think we would get a living organism out of this combo. Our DNA is pretty different from a spider's DNA.
Does that answer the question?(8 votes)
- As soon as I saw the spider I got chills down my spine.(7 votes)
- Is there something elephants eat to prevent cancer,or are they born with it? I don't know if they have something that humans don't in there bodies that can prevent it or not?(3 votes)
- They're born with it. Lucky Elephants.(4 votes)
- Does this mean if you gave humans spider genes we could spin silk?(4 votes)
- we will become spider man!!(2 votes)
- If so can we take bioluminescence/GFP and make a human glow?(3 votes)
- Unfortunately, no; this would not be possible. GFP is not only for bioluminescence. GFP can cause a cell to self-destruct. Additionally, the GFP gene is not very compatible with human genes.(4 votes)
- What would happen if we injected (GFP)into our body? Would we glow green?(3 votes)
- Yes, I suppose, then laser tag wouldn't be so fun with everyone glowing and all(5 votes)
- What if we found a way to get the 'fluorescent' gene (2:24) into humans? Would we start glowing?(3 votes)
- ok ik this is a dumb question but if we lost a tooth can we just use a shark tooth or a snake tooth to replace it?(2 votes)
- snake teeth and shark teeth look very different than human teeth, it would look silly and not work the same.(3 votes)
- Wow! So much information! I've no idea how I'm going to remember this all!! :D(3 votes)
Video transcript
- [Instructor] Hi, everyone. This video is all about
how the information in an organism's genes is
expressed as its traits. This occurs through the action
of molecules called proteins. But before we get into the details, let's start with the basics. What are traits? Well, traits are an organism's
observable characteristics, and there are some really weird but really cool traits out
there in the animal kingdom. Spiders, for example, can make seven different types of silk. Elephants have an amazingly
low risk of developing cancer. And some jellyfish have
the ability to glow. That's right! The crystal jelly can bioluminesce, or glow in the dark, all on its own. So now let's dive into the details of how these traits are expressed. Specifically, let's look at the jellyfish trait of bioluminescence. We know that an organism's
traits are affected by its genes. So let's travel into the nucleus of the crystal jelly's cells
to where its genes are found, on chromosomes. A chromosome shown here
is a cell structure that contains a coiled up DNA molecule. I personally like to think of chromosomes as the packaged and
organized version of DNA. A DNA molecule is made up of
subunits, called nucleotides. Nucleotides are often
called A, T, C, and G, which stand for adenine,
thymine, cytosine, and guanine. A gene is a specific stretch or a chunk of nucleotides
within a DNA molecule. So a chromosome and its
DNA are like a cookbook that contains recipes
for making an organism. Genes are the recipes. And just like how letters are
arranged in a specific order to form words in a recipe, the nucleotides in a gene are also arranged in a specific
order to convey information. So what does the cell make
with these gene recipes? The cell uses the information in genes to make other molecules called proteins. So our crystal jelly must
have genes on its chromosomes that are responsible for its
trait of bioluminescence. Because of work done by scientists, we now know that the jelly
fish's bioluminescence involves one gene in particular. The coding sequence of this gene is made up of roughly 700 nucleotides, all arranged in a specific order. And this gene acts like a
recipe for making a protein called green fluorescent
protein, or GFP, for short. Whenever you hear the word fluorescent, just think glowy. GFP is a glowy protein
that can emit green light. And it's this presence of
GFP in the jelly fish's cells that allows the jellyfish to bioluminesce. But proteins can do so
much more than glow. There are thousands of tasks that different proteins carry out in order for cells to function. Some proteins help provide structure, some help move substances
into and out of the cell, and others help carry
out chemical reactions. All proteins are made up of
subunits called amino acids which are connected in a chain. It's the order of nucleotides in a gene that determines the order
of amino acids in a protein. And the order of amino acids is important because it determines the 3D shape that the protein will take on. And a protein's shape, in
turn, affects its function. For the GFP protein, this protein has a special
sequence of three amino acids that end up in the middle
of a barrel-like structure when the protein takes on its 3D shape. These amino acids form
the part of the protein that can fluoresce. They can absorb energy and then emit that energy as green light. So to sum it all up, genes affect traits through the actions of the
proteins that they encode. The order of nucleotides in a gene determines the order of
amino acids in a protein. And a protein's amino acids
determines its structure and its function. The crystal jelly's bioluminescence and the discovery of GFP highlight why this
knowledge is so important. Scientists have used
the GFP gene and protein to make countless discoveries. Now, researchers can
attach GFP to other things, such as other proteins or viruses, making them visible
through bioluminescence and easy to track. GFP has made the invisible visible, and it's allowed researchers
to learn how neurons develop and how cancer cells spread. And all of this research started with wondering about a single trait observed in the crystal jelly. Similarly, scientists are
studying the properties of spider silk proteins in order to make new
biocompatible materials. And they're also studying elephants for clues about how to
prevent cancer in humans. What animal trait do you think will lead to the next big discovery?