Chapter 6- Cell division

Question 1

What are the two main types of cell division?

Answer 1

Mitosis

Meiosis

Question 2

What is mitosis?

Answer 2

2 identical daughter cells are created
1 cell division
Used for growth and repair
Form of a-sexual reproduction

Question 3

What is meiosis?

Answer 3

4 genetically different gametes are created
2 cell division
Also known as reduction division
Produce gametes for sexual reproduction

Question 4

What is chromatin?

Answer 4

Unwound DNA - accessible to enzymes

Found inside the nucleus during interphase- DNA tightly packs into chromosomes

Question 5

What are homologous pairs?

Answer 5

Both chromosomes contain the same genes but may be different versions of the same gene

Question 6

During prophase, what is the DNA found as?

Answer 6

2 identical sister chromatids connected by a centromere

Question 7

What happens in growth phase 1?

Answer 7

First stage of cell cycle
Cell is growing and preparing to divide
Stores energy for DNA replication and cell division 
Increases protein synthesis 
Organelles replicate

Question 8

What happens in DNA synthesis pahse?

Answer 8

DNA replicates

Chromosomes unravel into chromatin

Question 9

What happens in growth phase 2?

Answer 9

Grow and replace energy used in DNA replication
Mitochondria divide
Cell checks for damaged DNA from replication

Question 10

What happens in quiescence?

Answer 10

Specialised cells stop dividing here
Could also be for aging cells or damaged cells
Can be temporary or permanent
Temporary- contact inhibition

Question 11

What happens during interphase?

Answer 11

Nuclear membrane is intact 
DNA is uncondensed as chromatin 
DNA replicates
Organelles double
This is: growth phase 1+2, DNA synthesis and quiescence

Question 12

What happens during prophase?

Answer 12

DNA condenses into chromosomes
Nuclear membrane starts to break down
Centrioles move to the poles of the cell and start to produce spindle fibres

Question 13

What happens during metaphase?

Answer 13

Chromosomes line up at the equator or metaphase plate of the cell
Spindle fibres attach to the centromere of each chromosome

Question 14

What happens during anaphase?

Answer 14

Sister chromatids are pulled apart to poles of cells due to spindle fibres shortening

Question 15

What happens during telophase?

Answer 15

Sister chromatids reach the poles of the cell
Nuclear membrane reforms
Cleavage furrow forms- pinching of cytoplasm

Question 16

What happened during cytokinesis?

Answer 16

Cytoplasm divides

2 genetically identical daughter cells are reproduced