cell division

Question 1

the cell cycle has three main phases

Answer 1

interphase
nuclear division
cell division

Question 2

what does mitosis produce

Answer 2

2 genetically identical diploid daughter cell

Question 3

what does meiosis produce

Answer 3

4 genetically non identical haploid daughter cell

Question 4

why does cell division occur

Answer 4

for them to grow
replaced damaged /worn out tissue

Question 5

mitosis uses

Answer 5

asexual reproduction
growth of tissues
replacement of lost cells
repairing damaged tissue

Question 6

meiosis uses

Answer 6

method of cell division takes place in reproductive organs
produces gametes
two haploid cells fuse in fertilisation diploid number restored

Question 7

interphase

Answer 7

during interphase cell increase in mass and size
normal cellular functions e.g synthesising proteins replicating its DNA

Question 8

three stages of interphase

Answer 8

g1
synthesis
g2

Question 9

what happens during g1

Answer 9

g1 phase where the cell elongates new organelles/proteins made

Question 10

what happens during synthesis

Answer 10

synthesis where cell replicates its DNA essential before cell can divide

Question 11

what happens during g2

Answer 11

cell keeps elongating and proteins needed for cell division made
.tubulin

Question 12

what is g0
and reasons why

Answer 12

permanent state for some cells
old age
differentiations
dna damage

Question 13

nuclear division / mitotic phase

Answer 13

follows interphase
cells growth stops during
mitotic phase divided into stages

Question 14

stages of mitosis

Answer 14

prophase
metaphase
anaphase
telophase

Question 15

what is cytokinesis

Answer 15

follows mitotic phase
after nuclear division
nucleus has divided into two genetically identical nuclei
cell divide
nucleus moves into each cell to create gentically identical daughter cell
cytoplasm constricting

Question 16

controls of the cell cycle

Answer 16

g1 checkpoint
g2 checkpoint

Question 17

g1 check point

Answer 17

checks cell size
nutrients
growth factors
dna damage

Question 18

g2 checkpoint

Answer 18

cell size
DNA replication
DNA damage

Question 19

what is a chromosome

Answer 19

chromosome is a long molecule of DNA
DNA has 2 strands wound into the shape of a double helix
each copy Called chromatid
joined by centimetre

Question 20

why are chromosomes only visible during cell division

Answer 20

chromosome
condense during mitosis

Question 21

prophase

Answer 21

chromosome condense
nuclear envelope begins to break down
centrioles move to the pole of the cell
begin to produce spindle fibre

Question 22

metaphase

Answer 22

spindle fibre attach to the centromere
centromere has a spindle fibre from each pole of the cell
chromosome move to the equator and line up

Question 23

telophase

Answer 23

nuclear envelop begin to reform
spindle fibre disappear
chromosomes coil become less distinct

Question 23

anaphase

Answer 23

spindle fibre contract
centromere of each chromosomes split
chromatid can be pulled to opposite poles of cell
v shape chromatid

Question 24

homologous chromosome

Answer 24

chromosome with the same gene in the same place (loci) .

Question 25

why are homologous pairs not clones

Answer 25

- Not clones of each other as inherited from each parent.

Question 25

alleles

Answer 25

code for the same protein but different versions

Question 26

daughter chromosomes

Answer 26

formed from pairs of chromatids that have spilts end up separate In mitosis and meiosis

Question 27

Telophase 1

Answer 27

same as mitiosis telophase Chromosomes arrive at opposite poles

Question 28

Prophase 1

Answer 28

chromosomes arranged side by side in homologous pairs pair of homologous chromosomes is called a bivalent Crossing over at chiasmata occurs

Question 29

Metaphase 1

Answer 29

bivalents line up along the equator of the spindle,bivalents line up

Question 29

Anaphase 1

Answer 29

homologous pairs of chromosomes are separate microtubules pull whole chromosomes to opposite ends of the spindle The centromeres do not divide

Question 30

cytokineses

Answer 30

the cell surface membrane pinches inwards - animals plant - vesicles from the Golgi apparatus gather along equator of the spindle and merge with each other to form the new cell surface membrane

Question 31

prophase 2 metaphase 2

Answer 31

the same

Question 32

Anaphase 2

Answer 32

Centromeres divide and individual chromatids are pulled to opposite poles creates four groups of chromosomes that half the number of chromosomes compared to the original parent cell

Question 33

Telophase 2

Answer 33

Nuclear membranes form around each group of chromosomes

Question 34

Independent assortment

Answer 34

random and depends on where genes lie on a chromosome

Question 35

During crossing over, the point where the chromosomes break is known as

Answer 35

chiasma

Question 36

Chromatids which have swapped sections with others are known

Answer 36

recombinant chromosomes

Question 37

Crossing over leads to the exchange of

Answer 37

alleles between homologous chromosomes