Cell Replication

Question 1

As cells get older

Answer 1

• they grow in size
• Until it becomes more and more difficult for nutrients to get into the cell fast enough,
• and for the waste to leave fast enough.
• So the cell will either stop growing or divide into two smaller cells

Question 2

Organisms reproduce either with

Answer 2

• Asexual Reproduction

* Sexual Reproduction

Question 3

What is Asexual reproduction?

Answer 3

• Is a method of producing offspring that does NOT involve the fusion of different gametes (eggs or sperm)
• Instead it is a process called mitosis
• Where exactly everything inside the cell is copied exactly
• Then divided into two daughter cells

Question 4

Why does MITOSIS Occur?

Answer 4

•	Reproduction
Single celled organisms, such as bacteria, divide to 
make new independent organisms.
•	Growth
•	Repair

Question 5

6 stages of mitosis?

Answer 5

I nterphase
P rophase
M etaphase
A naphase
T elephase
C ytokinesis

Question 6

what is the cells life cycle?

Answer 6

1. Cell reproduces
2. Lives
3. Dies – cell suicide or APOPTOSIS (cells have a certain life span – then they die. If they don’t die  cancer)

Question 7

What is apoptosis?

Answer 7

• Its function is to counter cell production and maintain an appropriate number of cells in the tissues.

Question 8

What happens in apoptosis?

Answer 8

• Instructions come telling the cell’s lysosomes (enzyme containing organelles) to make chemicals to kill itself.
• The lysosome then empties its contents into the cell causing the cellular components to be broken down.

Question 9

What do the enzymes do in cell replication?

Answer 9

• The enzymes slice up the DNA into tiny fragments.

* The enzymes make the cell change shape. It gradually shrinks and splits and repackages itself into smaller fragments.

Question 10

what is necrosis?

Answer 10

• This is cell death by accident or poisoning, overheating or when starved of oxygen.
• The cell swells and the membrane splits, which makes it messy

Question 11

What is the importance of cell death?

Answer 11

• Development changes in growing embryos
• Ridding tissues of old, infected or damaged cells
• Removing immune cells which attack “self” cells
• Removing cells which have sustained DNA damaged.
• However, too much apoptosis can have serious consequences

Question 12

what does the cell cycle represent?

Answer 12

the time for a newly formed cell to mature and then give rise to two new cells through the process known as mitosis

Question 13

What are the 3 events that the cell cycle consists of?

Answer 13

• Gap 1 (life)
• Synthesis (diving the chromosomes)
• Gap 2 (mitosis phases)

Question 14

what happens in cytokinesis?

Answer 14

, the cytoplasm of the cell is divided to produce two daughter cells

Question 15

what are the 2 types of cells in the body?

Answer 15

1. Somatic cells

2. Gametes or sex cells – sperm and egg.

Question 16

What are somatic cells?

Answer 16

body cells. Cell growth occurs by the process of MITOSIS and cytoplasmic division. Also repair of damaged or injured body tissues.

Question 17

What are gametes or sex cells?

Answer 17

sperm and egg

Question 18

sexual reproduction?

Answer 18

between a male and a female of the same species.

This results in GENETIC VARIATION

Question 19

what happens in interphase?

Answer 19

no. of organelles and amount of cytoplasm increases as it wants to divide

Question 20

what happens in prophase?

Answer 20

chromosomes shorten and thicken , spindle fibres form

Question 21

what happens in metaphase?

Answer 21

chromosomes line up

Question 22

what happens in anaphase

Answer 22

chromatids separate

Question 23

what happens in telophase

Answer 23

chromosomes become visible ans nuclear membrane is made two new nuclei

Question 24

what happens in cytokinesis

Answer 24

they separate and produce 2 new daughter cells

Question 25

what is a centrometre?

Answer 25

strands that hold it all together

Question 26

what is a chromatid?

Answer 26

two identical strands