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Molecular Genetics: RNA 234 Views


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Description:

In this video from our course on molecular genetics learn all about RNA.


Transcript

00:00

[ whoosh ]

00:01

We speak student!

00:03

[ whoosh ]

00:04

[ music ]

00:06

Molecular Genetics

00:08

RNA

00:10

A la Shmoop

00:11

[ music continues ]

00:13

We are here with Dr. Ruth Tennen

00:15

to talk about molecular genetics

00:17

here at Shmoop global headquarters

00:18

in Mountain View, CA.

00:20

And we're gonna cover genetic code and DNA/RNA structure.

00:24

All right, so, moving right along,

00:26

what is RNA? We've talked about DNA.

00:28

What is ribonucleic acid?

00:31

Yeah, so, it's very similar to DNA,

00:33

but it has that extra oxygen.

00:34

So it's also a polymer of nucleotides.

00:39

One big difference is, rather than the thymine

00:41

as one of the bases, it's uracil. So "T" goes to "U."

00:45

- Got it. - But they're basically the same.

00:46

Otherwise, their function's very different.

00:48

And there's other differences as well. So, for example,

00:50

DNA is always double-stranded,

00:52

RNA tends to be single-stranded, then fold back on itself.

00:55

So they have different functions in the cells,

00:57

but they, structurally, are pretty similar.

00:58

Got it. Okay.

01:00

Then we have subsets of RNA -

01:05

mRNA, rRNA, tRNA.

01:07

Can you explain to us what are those elements

01:10

and how do they function?

01:11

[ whooshing ]

01:12

What are the different kinds of RNA?

01:15

So, kind of a major RNA that we always hear about is mRNA,

01:19

which is the intermediate between DNA and protein.

01:21

So DNA gets transcribed into mRNA, which gets translated into protein.

01:25

So that's kind of like the "famous" RNA.

01:27

But there are what's called non-coding RNAs,

01:30

that aren't turned into proteins, basically.

01:32

So tRNAs are transfer RNAs and those are involved in protein synthesis.

01:36

They help with the ribosome.

01:39

There are ribosomal RNAs which, again,

01:40

they don't get turned into proteins, but they actually

01:42

function as RNAs.

01:45

But walk us through, like, how does it work?

01:48

What's the RNA process? Why do we need these interstitial steps

01:51

to make things happen so that everything's okay?

01:54

Is it like a human checking mechanism to be sure that genes

01:57

are all happy and healthy?

01:58

And if they don't, the cell goes away,

02:01

so we heal properly?

02:03

[ whooshing ]

02:04

Why do we need RNA?

02:06

One reason is that DNA -- you want it to be super stable.

02:09

Right? Because it gets passed down through all the generations

02:12

- and we need to keep it the same. - Sure.

02:14

By having an intermediate, basically you can say,

02:16

"Okay, I wanna turn on this gene.

02:18

And I'm gonna make a ton of copies of the messenger RNA."

02:20

So you can have a ton of different copies

02:21

that ultimately will get degraded when they're not needed anymore.

02:24

Whereas you wouldn't wanna chew up the DNA

02:26

when it wasn't needed anymore.

02:27

So it's kind of a way of...

02:29

How do they get degraded?

02:29

So this is like taking a DVD and copying it,

02:32

and copying it again and again and again

02:34

and after a while it just -- like the data isn't as clear?

02:38

So each copy, actually, is originally from the DNA.

02:40

So each copy's just as good as the previous one.

02:42

But, eventually, let's say a cell wanted to turn on a gene

02:46

to do a certain thing.

02:47

So it said, "Okay, I'm gonna need to metabolize sugar right now

02:50

so I gotta turn on my sugar-metabolizing gene."

02:52

And then the sugar goes away;

02:53

it doesn't need that protein anymore that would do that.

02:56

So then there are enzymes that come in

02:57

and just chew up and get rid of the RNA. It's extra.

02:59

[ woo-woo-woo ]

03:01

Got it. So it degrades not in its quality gets less;

03:05

it degrades in that its utility is lower.

03:07

Exactly. The abundance ends up going down

03:09

when it's not needed anymore.

03:09

Got it. And our body has stuff that regulates that?

03:13

Is that like the...?

03:14

You know, I don't know in terms of actual hormones and things,

03:17

but at the cellular level, there's like a million enzymes

03:19

that are always pucking around and --

03:21

Basically, these processes are super important,

03:22

so there's tons of layers of regulation

03:24

just to make sure everything's pretty tightly constrained.

03:26

Got it. 'Cause you've got a lot of replications happening.

03:28

I mean, it kind of reminds me of a computer.

03:29

It's like if you don't have lots of checks in your database,

03:31

- Exactly. - you're gonna print bad data.

03:33

[ whoop ]

03:34

What is RNA?

03:37

What are the different kinds of RNA?

03:41

Why do we need RNA?

03:45

[ woo-woo-woo ]

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