Mitosis

Question 1

Describe prophase.

Answer 1

Chromosomes condense, visible, chromatids joined by centromere, centrioles move to opposite ends, form spindle fibres, nuclear envelope breaks down.

Question 2

Apart from interphase, what is the longest stage of mitosis?

Answer 2

Prophase

Question 3

Why are chromatids that are joined by the centromere called sister chromatids?

Answer 3

They have the same material

Question 4

Describe metaphase.

Answer 4

Chromosomes line up along the middle of the spindle (equator), centromeres attach to spindle fibres at equator.

Question 5

Describe anaphase.

Answer 5

Centromeres split, spindle fibres shorten, pulls 1 chromatid of each chromosome to opposite poles, ends when separated chromatids reach the poles and spindle fibres break down.

Question 6

What forms the spindle fibres?

Answer 6

Centrioles

Question 7

Describe telophase.

Answer 7

Chromosomes unravel and nuclear envelope reforms.

Question 8

Describe cytokinesis.

Answer 8

Protein filaments inside membrane contract to divide cell into 2.

Question 9

What are chromosomes made out of?

Answer 9

DNA and a type of protein allied histone

Question 10

How many pairs of chromosomes are there in a human?

Answer 10

23

Question 11

What is a centromere?

Answer 11

Middle of chromosome, holds two chromatids together, point at which microtubules of spindle attach.

Question 12

What is a chromatid?

Answer 12

One of two identical copies of a chromosome, joined at the centromere prior to cell division.

Question 13

How many chromosomes does a diploid human cell have?

Answer 13

2

Question 14

What does the term diploid mean?

Answer 14

Having two complete sets of chromosomes.

Question 15

What is an organisms ploidy level?

Answer 15

The number of complete sets of chromosomes in an organism.

Question 16

What does the term haploid mean?

Answer 16

Haploid cells contain HALF the diploid number of chromosomes

Question 17

What is a homologous pair of chromosomes?

Answer 17

Pairs of chromosomes that have the same genetic material.

Question 18

What are the 4 phases of the cell cycle?

Answer 18

Growth 1, synthesis, growth 2, mitosis.

Question 19

What happens in growth 1 of the cell cycle?

Answer 19

Cellular contents, excluding the chromosomes are duplicated.

Question 20

What is the order of the stages in mitosis?

Answer 20

Interphase, prophase, metaphase, anaphase, telophase, cytokinesis

Question 21

What phases of the cell cycle does interphase cover?

Answer 21

All 3 of them

Question 22

What happens in the synthesis phase of the cell cycle?

Answer 22

Each of the 46 chromosomes is duplicated by the cell.

Question 23

What happens in the growth 2 phase of the cell cycle?

Answer 23

The cell “double checks” the duplicates chromosomes for error, making any needed repairs.

Question 24

What is mitosis?

Answer 24

A type of cell division in which the two daughter cells have the same number of chromosomes and are genetically identical with each other and the parent cell.

Question 25

What is the longest phase of the cell cycle?

Answer 25

Growth 1

Question 26

State 3 reasons why mitosis is important.

Answer 26

Genetic stability through identical copies, growth and repair of tissues and dead cells, asexual reproduction.

Question 27

What is an oncogene?

Answer 27

A gene with the potential to cause cancer

Question 28

How do oncogenes cause cancer?

Answer 28

They prevent cells from undergoing rapid cell death when critical functions are altered.

Question 29

How does cancer occur?

Answer 29

When some of the body's cells multiply in an abnormal way

Question 30

What is metastasis?

Answer 30

When cancer spreads to other organs

Question 31

What the four types of mutation?

Answer 31

Tumour suppressor genes, protooncogenes, apoptosis, angiogenesis

Question 32

Describe tumour suppressor genes as a type of mutation.

Answer 32

Normal genes slow cell division (mitosis), if they mutate they fail to act as a brake.

Question 33

Describe protooncogenes as a type of mutation.

Answer 33

Clock genes which trigger cells to divide, mutation of oncogenes leads to rapid division, where proteins are produced fair in excess.

Question 34

Describe apotosis as a type of mutation.

Answer 34

Cell death by white blood cells (cell suicide) caused by lysosomes, mutation to a cell will stop the lysosomes from doing this, so cells will grow.

Question 35

Describe angiogenesis as a type of mutation.

Answer 35

Ability to form capillaries to supply blood to the growing and dividing cells.