2.1.6 cell division

Question 1

what happens during prophase

Answer 1

nuclear membrane disintegrates
spindle fibres form
chromatin becomes visible

Question 2

what happens during metaphase

Answer 2

chromosomes line up along equator

Question 3

what happens during anaphase

Answer 3

chromatids pulled apart by spindle fibres contracting

Question 4

what happens during telophase

Answer 4

nuclear envelope reforms
cleavage furrow forms

Question 5

what happens during cytokinesis

Answer 5

cytoplasm reforms
2 identical somatic diploid cells are produced

Question 6

what is G0

Answer 6

resting stage for damaged cells, apoptosis, specialised cells

Question 7

what is G1 for

Answer 7

cell growth
organelle duplication
protein synthesis

Question 8

what is S phase for

Answer 8

DNA replication

Question 9

what is G2 for

Answer 9

organelle duplication
protein synthesis

Question 10

what does the G1 checkpoint do

Answer 10

checks for cell size
growth factors
organelle duplication
checks for damage

Question 11

what does the G2 checkpoint do

Answer 11

checks for mutations
DNA is checked

Question 12

what is the checkpoint in mitosis

Answer 12

spindle assembly checkpoint

Question 13

what is interphase

Answer 13

G1, S phase and G2

Question 14

how do you calculate mitotic index

Answer 14

cells in mitosis/total number of cells

Question 15

what types of cells does mitosis produce

Answer 15

somatic diploid cells

Question 16

what types of cells does meiosis produce

Answer 16

haploid gametes

Question 17

what is homologous chromosome

Answer 17

each pair consists of one maternal and one paternal chromosome
(same gene, different alleles)

Question 18

what is a stem cell

Answer 18

an undifferentiated cell that can specialise to make a specialised cell

Question 19

what does totipotent mean

Answer 19

can differentiate into all cell types

Question 20

what does pluripotent mean

Answer 20

can differentiate into specific cells

Question 21

what does unipotent mean

Answer 21

can differentiate into one cell type

Question 22

describe a neutrophil

Answer 22

engulfs bacteria by phagocytosis
has lysosomes
has a nucleus that moves
destroys pathogens

Question 23

describe an erythrocyte

Answer 23

biconcave disc
no nucleus
haemoglobin to carry oxygen round body

Question 24

describe a muscle cell

Answer 24

many mitochondria
lots of protein
contracts and relaxes

Question 25

describe a rod cell

Answer 25

receptor membranes on one end
full of pigment to help you see

Question 26

describe a goblet cell

Answer 26

cup shape to hold mucus

Question 27

describe a nerve cell

Answer 27

many dendrites
myelin sheath carries electrical impulses along cell

Question 28

describe a sperm cell

Answer 28

acrosome
flagellum
many mitochondria
haploid nucleus (gamete)

Question 29

describe a bone cell

Answer 29

contains lots of calcium
provides body with structure

Question 30

describe a root hair cell

Answer 30

large surface area
thin walls
many mitochondria
long

Question 31

what are the stages of meiosis in plants

Answer 31

anaphase I –> meiosis II

Question 32

what happens during prophase I

Answer 32

nuclear envelope disintegrates
chromosomes condense
spindle fibres form
bivalent formation = homologous chromosomes form a bivalent via synapsis
crossing over = non-sister chromatids intertwine and exchange segments which changes mixture of genetic info

Question 33

what happens during metaphase I

Answer 33

bivalents line up at equator
centromere attaches chromosomes to spindle
random assortment mixes up genetic info

Question 34

what happens during anaphase I

Answer 34

homologous chromosomes in each bivalent pulled to each pole by spindle fibres contracting
(centromeres don’t divide)

Question 35

what happens during telophase I

Answer 35

nuclear envelopes reform
cytokinesis occurs
brief interphase
chromosomes uncoil

Question 36

what happens during prophase II

Answer 36

nuclear envelope disintegrates
chromosomes condense
spindle fibres form
centrioles to opposite poles
(spindle in plants turns 90°)

Question 37

what happens during metaphase II

Answer 37

chromosomes are lined up at equator with chromatids randomly assorted

Question 38

what happens during anaphase II

Answer 38

chromosomes pulled apart

Question 39

what happens during telophase II

Answer 39

two cells divide to make 4 genetically different haploid gametes (recombinants)
(a terrad in plants)