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Molecular Genetics: Mitosis vs. Meiosis 440 Views


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Description:

In this video from our course on molecular genetics, learn about mitosis, meiosis and the difference between the two.


Transcript

00:00

[ whoosh ]

00:01

We speak student!

00:03

[ whoosh ]

00:05

Molecular Genetics

00:07

Mitosis versus Meiosis

00:10

A la Shmoop

00:12

So we're here talking about DNA replication now

00:15

with Dr. Ruth Tennen, who is a guru on the subject.

00:17

So, Dr. Ruth, what are the two main types of cells

00:21

in the human body?

00:22

So there's two types.

00:24

One is the somatic cell.

00:26

So, those are kind of the regular cells that you think about.

00:28

So, your liver cells or your skin cells. Muscle cells.

00:32

The other type is germ cells, or sex cells.

00:35

And those are the cells that combine to form a new human. [egg and sperm combine to make a new human]

00:38

[ crowd oohs ]

00:39

Got it. So "somatic" - S-O-M-A-T-I-C.

00:43

Where does that -- what's "som"?

00:44

- It's not from "South and Market," right? - No.

00:46

It was done before that.

00:47

What is somatic?

00:49

So "soma" means body.

00:50

So it's basically body cells.

00:51

Got it.

00:53

Okay. So how do somatic cells relate with germ cells?

00:58

Are they sort of coopetition? Are they frenemies?

01:01

Are they just -- do they hate each other?

01:03

Do they live separately?

01:05

They're pretty happy together. They're in different parts --

01:06

So, basically, your whole body is composed of somatic cells

01:08

and then just sperm and egg cells.

01:09

Those are the only germ cells you have.

01:11

And the germ cells are what ultimately combine to form your body.

01:15

So they're required to form the somatic cells also.

01:17

And how does a germ cell -- cause, you know,

01:19

a normal person, you think "germ, ooh, that's bad.

01:21

I wanna not have any germs."

01:23

But, in fact, that would be bad, right?

01:25

Bad to not have germ cells, yeah.

01:27

It would be difficult to reproduce if you were a human.

01:28

Hmm. So we need the germs to reproduce?

01:32

- Right. - That just seems counterintuitive, but take it. There.

01:35

Okay, next. Five-dollar word - mitosis.

01:39

We touched on this a little bit earlier.

01:40

But give us a good definition for mitosis.

01:43

So, mitosis is the process of cell division that somatic cells undergo. [cells divide]

01:48

They take their duplicated DNA and they divide it into two new daughter cells.

01:51

[ ding! ]

01:52

Got it. So this is like the pants zipper thing

01:54

with the ATCG?

01:55

So, it's a little bit after that.

01:57

During -- if you think about the cell cycle,

01:59

which is basically how a cell goes from one to two cells,

02:01

it starts off by replicating its DNA.

02:04

And then at another point in the cycle is when the mitosis happens.

02:06

And mitosis is just basically the physical separation

02:08

of the DNA into two daughter cells.

02:11

Got it. Okay.

02:12

Then what's "meiosis"? M-E-I-O-S-I-S.

02:16

"Me-osis" or "my-osis" is basically the same idea as mitosis,

02:19

but it's for the germ cells, or the sex cells. [egg and sperm]

02:21

And it's a little bit different because meiosis starts with

02:25

- a normal cell that has two copies of every gene. - Mm-hmm.

02:28

And then there are two stages of meiosis -

02:30

one and two. And, ultimately, at the end, you end up,

02:32

rather than having two copies, just having one copy of each gene in the cell.

02:35

And that's what the egg and the sperm are.

02:36

One copy that can combine to ultimately form a diploid cell.

02:40

Got it. Fair enough.

02:42

Okay. Wow. DNA replication.

02:44

A la Dr. Ruth.

02:48

What are the two main types of cells in the human body?

02:52

What is mitosis?

02:54

What is meiosis?

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