3.2.2- Cell Division

Question 1

What is the cell cycle?

Answer 1

The regular cycle of cell division separated by periods of growth

Question 2

Importance of cell cycle

Answer 2

1. Growth and Development.
2. Replace old or damaged cells.
3. Produce new cells.
4. Differentiation- process by which cells become specialised

Question 3

Key Stages of the cell cycle

Answer 3

interphase, mitosis, cytokinesis

Question 4

Stages of the cell cycle

Answer 4

Growth of cell

Synthesis of DNA polymerase

DNA replication

Preparation for cell division

Mitosis (nuclear division)

Cytokinesis

Question 5

Importance of growth

Answer 5

Means you have enough organelle and enough space for them. Also means you have more mitochondria for energy

Question 6

Importance of synthesis of DNA polymerase

Answer 6

Forms backbone of DNA and makes sure there is enough

Question 7

Importance of DNA replication

Answer 7

new cells are able to receive an accurate copy of the organism’s genetic information; this allows for healthy function cells and therefore the organism has 23 pairs of chromosomes

Question 8

Importance of prep for cell division

Answer 8

Checkpoint so harmful cells are detected and removed

Question 9

Importance of Mitosis

Answer 9

Form 2 nuclei with 23 pairs of chromosomes each

Question 10

Importance of Cytokinesis

Answer 10

Creates 2 identical separate cells

Question 11

Cell Arrest

Answer 11

Cell leaves the cell cycle and stops dividing to prevent overcrowding

Referred to as the G0 phase and happens between G1 and S

Question 12

Mitosis

Answer 12

Process of nuclear division which produces 2 identical daughter cells

Question 13

Importance of mitosis

Answer 13

growth, repair, reproduction, differentiation

Question 14

Diploid

Answer 14

23 pairs of chromosomes- 2 complete sets

Question 15

Centromere

Answer 15

Area where the chromatids of a chromosome are attached & spindle fibres attach

Question 16

Chromatid

Answer 16

one half of a duplicated chromosome- single strand of DNA

Question 17

1 chromosome before mitosis

Answer 17

1 chromatid per chromosome

Question 18

1 chromosome after replication

Answer 18

2 sister chromatids per chromosome

Question 19

Stages of Mitosis

Answer 19

prophase, metaphase, anaphase, telophase

Question 20

Prophase

Answer 20

Preparation- chromosomes condense, become visible while nuclear membrane breaks down

Question 21

Metaphase

Answer 21

Chromosomes line up in the middle of the cell while spindle fibres form and attach to centromere

Question 22

Anaphase

Answer 22

Spindle fibres shorten and sister chromatids are pulled apart as chromosomes are pulled to opposite poles of the cell

Question 23

Telophase

Answer 23

2 new nuclear membranes form and chromosomes decondense (become long, thin and less visible)

Question 24

uncontrolled cell division can lead to…

Answer 24

Tumours and cancer

Question 25

Why does uncontrolled cell division occur?

Answer 25

It is often a result of mutated genes

Question 26

How do cancer treatments disrupt the cell cycle?

Answer 26

Prevent DNA from replicating (S phase of Interphase)

Inhibit spindle fibre formation and action (metaphase and anaphase)

Question 27

Mitotic index

Answer 27

the ratio between the number of cells undergoing mitosis to the total number of cells.

Question 28

asexual reproduction

Answer 28

A reproductive process that involves only one parent and produces offspring that are identical to the parent.

Question 29

Binary fission

Answer 29

A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size

Question 30

How do bacteria divide?

Answer 30

binary fission

Question 31

step 1 & 2 of binary fission in prokaryotes

Answer 31

DNA unravels and uncoils- the free floating DNA uncondenses- while both DNA and plasmid replicates

Question 32

Step 3 of binary fission

Answer 32

The cell grows and elongates as replicated dna moves to different opposite poles of the cell

Question 33

Step 4 of binary fission

Answer 33

Cell membrane starts to divide (equator constricts to separate the 2 cells)

Question 34

step 5 of binary fission

Answer 34

Cell membrane divides completely and leaves you with two identical daughter cells/clones