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Information Exchange
And they'll be just massive.
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I had read on Wikipedia that sometimes it will take five hours just for a flock of these to come by.
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And so what are you getting with a flock?
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Well you're getting protection.
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And so if you look at all of them each of these birds is looking in a different direction.
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And so they are looking for predators.
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And so it would be really hard to sneak up on them.
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And so once these birds started living together they started living longer.
Information Exchange
And also if you're a bird of prey up here it's really hard to target one bird when you see this flock just moving over time.
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And so there's been this movement towards this learned behavior of flocking or cooperation.
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But they did that one generation at a time.
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If you didn't flock you were destroyed or killed.
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And then those genes for that were killed with you or that behavior was killed with you.
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And so over time we have this.
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Now we see that in wolf packs as well and cooperation in humans you would say as well.
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It's really hard to get along with other humans.
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But if you can cooperate you can do really really well.
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And so that's information.
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That's how it's used by organisms.
Information Exchange
And I hope that's helpful.
video_title
transcription
Biotechnology Review AP® Biology Biotech Topic Overview
Hello everyone.
Biotechnology Review AP® Biology Biotech Topic Overview
In today's video, we're going to be doing an overview for the topics in the AP Biology curriculum related to biotechnology.
Biotechnology Review AP® Biology Biotech Topic Overview
Now, this is just a small section of unit six of the entire AP Biology course and exam description, but it's a section that a lot of students struggle with or feel that they're not prepared for.
Biotechnology Review AP® Biology Biotech Topic Overview
We're going to go through all of the topics that appear in the biotechnology topic so that you're prepared to better understand these for class or for the AP Bio exam.
Biotechnology Review AP® Biology Biotech Topic Overview
Let's get started.
Biotechnology Review AP® Biology Biotech Topic Overview
One of the main goals of this topic is to explain the use of genetic engineering techniques in analyzing or manipulating DNA.
Biotechnology Review AP® Biology Biotech Topic Overview
There are so many different techniques within the realm of biotechnology.
Biotechnology Review AP® Biology Biotech Topic Overview
If you ever take a course in biotechnology or go on to study more biology, you'll find this out.
Biotechnology Review AP® Biology Biotech Topic Overview
But there's a few that are focused on in AP Biology.
Biotechnology Review AP® Biology Biotech Topic Overview
These are PCR, gel electrophoresis, DNA sequencing, and bacterial transformation.
Biotechnology Review AP® Biology Biotech Topic Overview
All of the smaller details of how to do each of these techniques is beyond what the exam is actually going to test you on.
Biotechnology Review AP® Biology Biotech Topic Overview
As long as you have a good conceptual understanding of each of these techniques, you should be in a good place for the AP Bio exam.
Biotechnology Review AP® Biology Biotech Topic Overview
Now, we're going to focus mostly on PCR, gel electrophoresis, and genetic transformation today, because DNA sequencing is not covered very frequently on the exam and it's changed so much from the days of Sanger sequencing all the way up to next-gen sequencing, which a lot of scientists use now, that you really don't need to get into the details of this for AP Bio.
Biotechnology Review AP® Biology Biotech Topic Overview
Basically, what you need to know about DNA sequencing is that it's the process of determining which nucleotides come in which order in a sample of DNA.
Biotechnology Review AP® Biology Biotech Topic Overview
Now, we can do this at a much lower cost and we're able to sequence short pieces of DNA really, really quickly for study in modern labs.
Biotechnology Review AP® Biology Biotech Topic Overview
Sequencing an entire organism's genome is still a little bit tricky, but in the future we may have the ability to see every individual's complete genome in order to personalize and tailor medicine towards them.
Biotechnology Review AP® Biology Biotech Topic Overview
But that is a topic for the future.
Biotechnology Review AP® Biology Biotech Topic Overview
Let's get back to PCR.
Biotechnology Review AP® Biology Biotech Topic Overview
So the main idea of PCR is making lots of copies of DNA from a small sample.
Biotechnology Review AP® Biology Biotech Topic Overview
With PCR, we can make a lot of copies in a relatively short amount of time.
Biotechnology Review AP® Biology Biotech Topic Overview
What you need to know about PCR is that there are special machines that you can put your DNA sample after preparing it into.
Biotechnology Review AP® Biology Biotech Topic Overview
And then those machines go through cycles to do these three things.
Biotechnology Review AP® Biology Biotech Topic Overview
First, it heats up the DNA, which denatures it or separates it into two different strands.
Biotechnology Review AP® Biology Biotech Topic Overview
Then we're going to cool a little bit to 55 degrees Celsius and primers, which have been added to our DNA sample, which are these short fragments of DNA, will be able to anneal or connect to the separated DNA fragments.
Biotechnology Review AP® Biology Biotech Topic Overview
From there, we're going to heat it up a little bit more so that we have more of an affinity for elongation, more nucleotides, which are floating in our mix can attach to the open fragments of our DNA.
Biotechnology Review AP® Biology Biotech Topic Overview
So after one of these cycles, we're going to get two new strands of DNA.
Biotechnology Review AP® Biology Biotech Topic Overview
Then it goes through the same process again.
Biotechnology Review AP® Biology Biotech Topic Overview
They're denatured or separated.
Biotechnology Review AP® Biology Biotech Topic Overview
We have our annealing process, and then we have our elongation.
Biotechnology Review AP® Biology Biotech Topic Overview
And you see how each time we're able to double the amount of DNA.
Biotechnology Review AP® Biology Biotech Topic Overview
So PCR just stands for polymerase chain reaction.
Biotechnology Review AP® Biology Biotech Topic Overview
And we'll do this over and over and over again until we get enough copies of our DNA.
Biotechnology Review AP® Biology Biotech Topic Overview
After that, we can use this DNA to do a multitude of different things.
Biotechnology Review AP® Biology Biotech Topic Overview
One very popular use is getting a DNA fingerprint or doing gel electrophoresis.
Biotechnology Review AP® Biology Biotech Topic Overview
Now, hopefully in your ninth grade biology class, you learned that this is not a fingerprint actually from your finger, but instead it's a particular pattern of your DNA after we run it through a gel.
Biotechnology Review AP® Biology Biotech Topic Overview
The first step in gel electrophoresis or getting a DNA fingerprint is going to be cutting that DNA with restriction enzymes.
Biotechnology Review AP® Biology Biotech Topic Overview
Restriction enzymes are special enzymes that cut DNA at specific recognition sites that are usually only a few base pairs in length.
Biotechnology Review AP® Biology Biotech Topic Overview
Sometimes these are palindromic, meaning they read the same forwards and backwards.
Biotechnology Review AP® Biology Biotech Topic Overview
But after that cut is made, we'll get what's called sticky or blunt ends at the edges of our DNA.
Biotechnology Review AP® Biology Biotech Topic Overview
And a sticky end is when we have bases that are unpaired after a cut.
Biotechnology Review AP® Biology Biotech Topic Overview
So let's see what that means.
Biotechnology Review AP® Biology Biotech Topic Overview
So we'll have our sequence of DNA.
Biotechnology Review AP® Biology Biotech Topic Overview
The restriction enzyme will recognize a specific sequence and cut along that site to give us two separate fragments of DNA.
Biotechnology Review AP® Biology Biotech Topic Overview
For example, BamH1 cuts our DNA between the two Gs in the sequence whenever it encounters it along the strand.
Biotechnology Review AP® Biology Biotech Topic Overview
After we've prepared our DNA by cutting it with restriction enzymes, then we can put it in a gel.
Biotechnology Review AP® Biology Biotech Topic Overview
Our gel is a matrix-like material with tiny little holes in it that's gonna allow our DNA to travel through it.
Biotechnology Review AP® Biology Biotech Topic Overview
Usually we put a marker or a sample of DNA that we know the exact fragment lengths of in the very first well, which is at the top of our gel.
Biotechnology Review AP® Biology Biotech Topic Overview
And then the other DNA samples that we're analyzing are gonna be loaded into the next wells, usually with a dye, and we're doing this with a micro pipette.
Biotechnology Review AP® Biology Biotech Topic Overview
Once we've loaded all of our samples in, what we'll do is we'll attach electrodes.
Biotechnology Review AP® Biology Biotech Topic Overview
So we're running charges.
Biotechnology Review AP® Biology Biotech Topic Overview
Up here, this is a negative charge, and down here, this is a positive charge.
Biotechnology Review AP® Biology Biotech Topic Overview
One very important thing to remember about the properties of DNA is that DNA is negatively charged.
Biotechnology Review AP® Biology Biotech Topic Overview
So if we run an electric current through this gel, DNA will start to travel towards the positive end.
Biotechnology Review AP® Biology Biotech Topic Overview
But remember, in each of these samples, we've chopped our DNA up.
Biotechnology Review AP® Biology Biotech Topic Overview
So as it travels down towards the positive end of our gel, we're gonna see the DNA start to separate because each of these fragments is actually a different length.
Biotechnology Review AP® Biology Biotech Topic Overview
Our marker here is used for estimating the size of our DNA, but one thing we know for sure is that as the DNA travels down the gel, the longer fragments or the larger ones are gonna stay closer to the top or closer to the wells, and the smaller fragments are gonna be able to travel farther down the gel.
Biotechnology Review AP® Biology Biotech Topic Overview
So when the electric current is applied, the negatively charged DNA is gonna move towards the positive end of the gel.
Biotechnology Review AP® Biology Biotech Topic Overview
But in each sample, each of these fragments are gonna be different lengths, so we'll see different bands for the separation of the DNA molecule.
Biotechnology Review AP® Biology Biotech Topic Overview
One way I like to remember this is that if you have a race between one really, really large, probably out of shape person, and one really, really tiny, pretty nimble fit person, the person who is smaller is gonna be able to run faster and win the race.
Biotechnology Review AP® Biology Biotech Topic Overview
And so that is what this DNA is doing.
Biotechnology Review AP® Biology Biotech Topic Overview
They're able to get through all of these holes in the gel faster because it's a smaller fragment and a smaller piece.
Biotechnology Review AP® Biology Biotech Topic Overview
You should be able to know the closer this is to where the wells are, the larger it is, the closer our DNA is to the positive end of our gel, the smaller it is.
Biotechnology Review AP® Biology Biotech Topic Overview
So now that we know we can separate DNA based on size, what can this help us with?
Biotechnology Review AP® Biology Biotech Topic Overview
Gel electrophoresis has a lot of purposes, from DNA analysis at a crime scene, paternity testing, looking at how closely two organisms are related, evolutionarily, but let's back it up to a crime scene.
Biotechnology Review AP® Biology Biotech Topic Overview
If we have, for example, our evidence from the crime scene, which is DNA, and we wanna compare it to our suspects that we have in our case, what we can do is look at the banding pattern or the bands from the evidence DNA and compare that to the bands of the suspects.
Biotechnology Review AP® Biology Biotech Topic Overview
Based on these banding patterns, we can see that suspect three is a really good match with our evidence, and we might have just solved the crime.
Biotechnology Review AP® Biology Biotech Topic Overview
We'll also use restriction enzymes and gel electrophoresis when we're doing genetic transformation.
Biotechnology Review AP® Biology Biotech Topic Overview
And what we're doing with genetic transformation is inserting a gene of one organism into another organism so that it can display a new trait.
Biotechnology Review AP® Biology Biotech Topic Overview
Because of the central dogma, we're able to do this because virtually all organisms use the same universal genetic code.
Biotechnology Review AP® Biology Biotech Topic Overview
A lot of times we'll do this with bacteria and plasmids, but what is a plasmid?
Biotechnology Review AP® Biology Biotech Topic Overview
A plasmid is a circular double-stranded piece of DNA that's usually found in bacteria.
Biotechnology Review AP® Biology Biotech Topic Overview
It's extra chromosomal, meaning it doesn't belong inside the bacteria's chromosome, but bacteria will express or produce proteins from the DNA in these plasmids, and they'll replicate the plasmids whenever that bacteria divides as well.
Biotechnology Review AP® Biology Biotech Topic Overview
We use genetic engineering in a lot of fields, including agriculture, for example, inserting genes for pest resistance or fungal resistance into certain plants, in bioremediation, where we've genetically engineered bacteria to uptake oil at oil spills, or even in gene therapy in medicine.
Biotechnology Review AP® Biology Biotech Topic Overview
We've even used bacteria to produce insulin for humans before.
Biotechnology Review AP® Biology Biotech Topic Overview
So how do we get an organism like bacteria to actually express a new trait that wasn't in its DNA before?
Biotechnology Review AP® Biology Biotech Topic Overview
Here we're looking at a sample of DNA that's been added to bacteria to make it glow green.
Biotechnology Review AP® Biology Biotech Topic Overview
So a very simple version of this is that we start with a plasmid, and we're gonna cut it with that restriction enzyme.
Biotechnology Review AP® Biology Biotech Topic Overview
Our foreign DNA, or our DNA from the other organism, is gonna be cut as well, and then those sticky ends will attach to give us recombinant DNA here, meaning DNA from one organism has taken up DNA from another, and DNA ligase is gonna join our sticky ends together to form our recombinant plasmid.
Biotechnology Review AP® Biology Biotech Topic Overview
Once we have a recombinant plasmid, we'll go through several laboratory techniques to make this bacterial cell competent, meaning it'll take up that new plasmid, and once it does, we say that it's transformed.