B2- Cell Division And Differentiation Flashcards Preview

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Flashcards in B2- Cell Division And Differentiation Deck (17)
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1

What is a chromosome?

A long thin thread of DNA

2

How many chromosome do humans have?

23 pairs (46 in total)

3

What is a gene? What does it do?

A section of DNA In a chromosome
- it controls characteristics

4

What are the 4 Base pairs?

A-T
C-G

5

What are gametes?

sex cells and only contain 23 chromosomes, e.g sperm and egg cells which combine together and share their chromosomes

6

Name and describe stage 1 of cell division

Interphase, this is the longest part
-sub cellular structures increase
- cell replicates it DNA to form 2 copies of each chromosome
- grows bigger + increase in mass

7

Name and describe stage 2 of cell division

Mitosis
- in this process one set of chromosomes is pulled to each end of the cell and the nucleus divides

8

Describe stage 3 of cell division

Cytoplasm and the cell membrane divide to form 2 identical daughter cells

9

Where are stem cells found in an animal?(2)

-early human embryos
-adult bone marrow

10

Name 2 ways in which stem cells can be used to fix problems in the human body

-be transferred to replace faulty cells i sick people
- injected into spine of paralysed people to make more nerve cells
- make insulin producing cells for people with diabetes

11

Name 2 reasons why someone will be against the use of stem cells

- by using embryos you are ending a potential life (or from a religious point of view killing actual life)
- you could potentially clone people if you splint the embryo in 2

12

What do scientist say in argument to the issues raised by the use of stem cells? (Apart from the fact that they can help people)

- more embryos die than live so it just better that they are used
- to prevent cloning some some scientist have began taking stem cells from a much earlier stage, blastocyst, which doesn't allow cloning

13

Whats so special about stem cells?

They are undifferentiated so can develop into any specialist cell

14

Differentiation

When cells transform into specialist cells that perform a particular job and have particular sub cellular structures structures for this

15

How is differentiation different in plant cells?

Once cells specialise (differentiate)they can re-differentiate into other specialised cells. So if you took a rose's leave and plant it in the right conditions you would grow a rose plant

16

Where are stem cells found in a plant?

Everywhere

17

Why is the ability of body cells to divide important?

for growth / repair / replacement