Cell cycle

Question 1

Stages of interphase

Answer 1

G0 (some cells only)
G1
S Phase
G2

Question 2

Stages of mitosis

Answer 2

Prophase
Prometaphase
Metaphase
Anaphase
Telophase

Question 3

What occurs in G0

Answer 3

phase where there is no active preparation for cell division occurs. eg. in nerve cells, eye cells which do not actively divide

Question 4

What happens in G1

Answer 4

Increased cell size
Increased protein concentration
Regulatory proteins are made and activated

Question 5

What happens in S phase

Answer 5

DNA replication

Question 6

What happens in G2 phase

Answer 6

Preparation for mitosis/cytokinesis

Question 7

Most common form of replication in bacteria?

Answer 7

Binary fission

Question 8

What occurs in binary fission?

Answer 8

1. Circular bacterial DNA is attached to membrane by protein
2. DNA replication begins and proceeds bidirectionally around the circle
3. new DNA molecule is also attached to the inner membrane, near the original DNAs attachment site
4. Cell elongates, moving attachment sites further away
5. New membrane begins to form at the midpoint
6. 2 identical daughter cells are produced

Question 9

Which is more complex? Eukaryotic cell division or Prokaryotic? Why?

Answer 9

Eukaryotic

1. Due to large genome size, which must be entirely replicated. this is compared to bacteria which only have a relatively small circular DNA molecule
2. in proks, the dna is attached to the membrane and dna can be separated into 2 cells by cellular growth. in euks, dna is in the nucleus and requires the nuc envelope to be broken down and reformed

Question 10

What does the M phase consist of?

Answer 10

Mitosis

Cytokinesis

Question 11

How long does M phase typically last?

Answer 11

1 hour for most mammalian cells

Question 12

What is interphase?

Answer 12

the time between two successive M phases, where the cell undergoes preparation for cell division

Question 13

How is DNA in eukaryotic cells organised?

Answer 13

DNA is organised with histones and other proteins into chromatin, which are looped and packaged into chromosomes

Question 14

Karyotype

Answer 14

a standard arrangement of chromosomes,showing the number and shapes of the chromosomes representative of a species

Question 15

How many chromosomes does the human genome contain

Answer 15

46 chromosomes (23 pairs)

Question 16

homologous chromosomes

Answer 16

pairs of chromosomes which match in size and appearance. carries the same amount of genes. one is from the mother, one is from the father

Question 17

ploidy

Answer 17

number of complete sets of chromosomes in a cell

Question 18

haploid

Answer 18

one complete set of chromosomes

Question 19

diploid

Answer 19

two complete set of chromosomes

Question 20

polyploid

Answer 20

some organisms can have 4 or sometimes more sets of chromosomes

Question 21

sister chromatid

Answer 21

two identical copies of a chromosome produced when DNA is replicating

Question 22

centromere

Answer 22

part of the chromosome that holds the chromatids together, and are the site of the attachment of the spindle fibres that move the chromosomes

Question 23

prophase

Answer 23

chromosomes condense

centrosomes radiate microtubules and migrate to opposite poles

Question 24

prometaphase

Answer 24

microtubules attach to chromosomes

Question 25

metaphase

Answer 25

chromosomes align in centre of cell

Question 26

anaphase

Answer 26

sister chromatids separate and are pulled to opposite end of cell

Question 27

telophase

Answer 27

nuclear envelope reforms and chromosomes condense

Question 28

mitotic spindle

Answer 28

structure made of microtubules that pull the chromosomes into separate daughter cells

Question 29

centrosome

Answer 29

structure that is the microtubule organising center for animal cells

Question 30

what happens to the centrosome in S phase?

Answer 30

centrosome duplicates and each begin to migrate around nucleus, creating opposite poles

Question 31

kinetochores

Answer 31

site of spindle attachment. located on both sides of centromere

Question 32

what happens during cytokinesis

Answer 32

it is the phase where the parent cell divides into 2 daughter cell

Question 33

contractile ring

Answer 33

ring of actin filaments that forms at the equator of the cell perpendicular to the axis of what was the spindle at the beginning of cytokinesis