Mitosis

Question 1

What is a chromosome

Answer 1

A DNA molecule folded and condensed

Wrapped around a histone protein in eukaryotes.

Question 2

What forms after DNA replication

Answer 2

2 genetically identical sister chromatids

Question 3

Where are sister chromatids attatched

Answer 3

At the centromere

Question 4

Define homologous chromososome

Answer 4

Chromosomes with the same genes but potentially different alleles.

Question 5

Diploid cells

Answer 5

Cells with homolgous pairs of chromosomes

Question 6

Diploid is represented by…

Answer 6

2n

Question 7

Haploid cells

Answer 7

Cells with only one copy of the pair of chromosmes,

Half the number of chromosomes than diploids.

Question 8

Haploid cells are represented by…

Answer 8

n

Question 9

What type of cells can’t divide

Answer 9

Specialised and fully differentiated cells
e.g
Red blood cells

Question 10

What type of cells can divide

Answer 10

unspecialised cells

Question 11

3 main stages of the cell cycle

Answer 11

Interphase, mitosis and cytokenisis

Question 12

3 phases of interphase

Answer 12

G1
S
G2

Question 13

G1 phase of interphase, what happens?

Answer 13

Cell increases in size and new proteins and enzymes are made for DNA replication.

Question 14

S phase in interphase, what happens?

Answer 14

DNA replicates

Question 15

G2 phase in interphase, what happens?

Answer 15

Cell gets ready for division, new proteins and organelles are made.

Question 16

What stage of the cell cycle is where chromomes are not visible?

Answer 16

Interphase

Question 17

4 Stages of mitosis

Answer 17

Prophase, metaphase, anaphase, telophase

Question 18

Why is mitosis important

Answer 18

Allows organisms to grow
Allows organisms to replace cells in order to repair tissues
Results in genetically identical cells
Asexual reproduction in some organisms (not prokaryotes)

Question 19

What happens in prophase

Answer 19

Nuclear membrane breaks down
Centrioles move to the poles of the cell and make spindle fibres.
chromosomes condense and become visible.

Question 20

What happens in metaphase

Answer 20

Spindle fibres which attach to the centromere of each chromsome
Chromosomes align down the equtor of the cell.

Question 21

What happens in anaphase

Answer 21

Spindle fibres contract, dividing the centromere.

Sister chromatids are pulled apart to opposite poles pf the cell ( the chromatids appear as V shapes)

Question 22

What happens in telophase

Answer 22

Chromsomes reach the poles and the spindle fibres break down.
New nuclear membrane forms around the group of chromsomes
Chromosomes uncondense and begin to form chromatin again.

Question 23

What happens in cytokenisis

Answer 23

The cytoplasm divides; producing two genetically identical daughter cells

Question 24

Cell division in cancer

Answer 24

Uncontrolled cell division leading to tumours

Question 25

Cancer cells

Answer 25

Divide uncontrollably | Have a shorter cell cycle and divide more often.

Question 26

How are cancer cells dangerous

Answer 26

Unspecialised and have no function so they cause harm by damaging organs or blocking blood vessels to organs.

Question 27

What parts of the cell cycle to cancer treatments disrupt

Answer 27

DNA replication (interphase) Spindle formation/contraction (prevents anaphase) Cytokenisis

Question 28

Why do cancer treatments kill more cancer cells than healthy cells

Answer 28

Tumour cells divide more frequently than normal cells s the treatments target tumour cells more.