The cell cycle

Question 1

Gene

Answer 1

Length of dna that codes for a polypeptide or length of RNA

Question 2

Centromere

Answer 2

Region of chromosomes where two sister chromatids join together

Question 3

Cell cycle

Answer 3

Series of stages that a cell goes through as it grows and divides

Question 4

A photomicrograph of chromosomes in a cell

Answer 4

Karyotype

Question 5

Somatic cell

Answer 5

Any cell that isn’t a reproductive cell

Question 6

Sister chromatids

Answer 6

When chromosomes replicated, resulting two identical chromatids are sister chromatids

Question 7

Chromatids

Answer 7

one half of a Replicated chromosome

Question 8

Replication

Answer 8

The process by which DNA makes identical copies of itself

Question 9

Haploid

Answer 9

Only one set of chromosomes N

Question 10

Diploid

Answer 10

2 complete sets of chromosome

Question 11

Mitosis

Answer 11

Nuclear division which produces daughter cells genetically identical to each other and parent cell

Question 12

Chromatin

Answer 12

Material which makes up chromosomes when cell isn’t dividing, less condensed thread like structure during interphase

Question 13

Stages of cell cycle

Answer 13

Interphase ( G1, S, G2)
M phase (mitosis)
Cytokinesis

Question 14

What gene controls G1 phase

Answer 14

-p53 gene

Question 14

What happens during G1

Answer 14

• synthesis of specific enzymes
• growth
• organelles duplicate
• transcription of genes to make RNA

Question 15

What happens during S phase

Answer 15

• DNA replication
• when all chromosomes duplicated, each one consists of a pair of identical sister chromatids

Question 16

Order of S phase

Answer 16

• House keeping ( active in all types of cells) genes replicated first, usually inactive genes replicated last

Question 17

Process of G2 phase

Answer 17

• cells grow
• special chemicals ensure cell ready for mitosis by stimulating proteins involved in making chromosomes condense
• storage of energy

Question 18

Use of checkpoints

Answer 18

• prevent uncontrolled division
• detect and repair damage to DNA

Question 19

What’s the hay flick limit

Answer 19

• total number of times a cell can divide
• cancer and stem cells have no limit

Question 19

Proto - oncogene

Answer 19

Normal gene which when altered by mutation can become oncogene that contributes to cancer

Question 20

Function of proto oncogene

Answer 20

• some provide signals that lead to cell division
• others regulate apoptosis

Question 21

Apoptosis

Answer 21

• regulated and programmed cell death

Question 22

Why cells need to divide

Answer 22

For growth, tissue repair and asexual reproduction

Question 23

Asexual reproduction

Answer 23

• e.g. in amoeba and fungi like single cell yeasts

Question 24

What happens during cytokinesis

Answer 24

Cytoplasm divided between two daughter cells

Question 25

Supercoiled

Answer 25

When DNA molecule helix is twisted beyond its natural coiled state
- important for DNA packaging in cells allowing long DNA strand to fit in nucleus

Question 26

When is G0 and what is it

Answer 26

G0 is a resting phase after it’s done dividing or duplicating (mitosis)
- apoptosis
- differentiation

Question 27

When do chromosomes become supercoiled

Answer 27

• during mitosis ( prophase)

Question 28

What does uncontrolled cell division lead to

Answer 28

• tumours

Question 29

What are the checkpoints

Answer 29

• G1 ( restriction point)
• G2