cell division

Question 1

what is the purpose of mitosis

Answer 1

cell growth (increase in cell no.)
to repair (replacing damaged cells)
asexual reproduction

Question 2

what happens in G1

Answer 2

cell growth
organelles are produced and replicated

Question 3

what happens in the S phase

Answer 3

DNA replication

Question 4

what happens in G2

Answer 4

cell growth
energy stores

Question 5

what happens during mitosis

Answer 5

nuclear division

Question 6

what happens during cytokinesis

Answer 6

cell division

Question 7

what happens in G0

Answer 7

cells are unable to divide actively

Question 8

how is the cell cycle controlled

Answer 8

genetic checks to make sure DNA is mutation free

Question 9

what does the spindle assembly checkpoint check for

Answer 9

chromosomes attachment to spindle

Question 10

what does the G1 checkpoint check for

Answer 10

cell size
nutrients
growth factors
DNA damage

Question 11

what does the G2 checkpoint check for

Answer 11

cell size
DNA replication
DNA damage

Question 12

what happens during prophase

Answer 12

DNA coils to form chromosmes
nuclear membrane breaks down
centrioles move to opposite poles of cell creating spindle fibres

Question 13

what happens during metaphase

Answer 13

chromosomes attach to spindle fibres at the centromere
spindle fibres move chromosomes so they align at the equator of the cell

Question 14

what happens during anaphase

Answer 14

spindle fibres contract
centromere splits
chromatids separate
chromatids are pulled to opposite poles of the cell

Question 15

what happens during telophase

Answer 15

DNA uncoils to form chromatin
nuclear membrane reassembles
spindle fibres start to break down

Question 16

give the differences between animal and plant cells during mitosis

Answer 16

plant
- centrioles only appear during mitosis
- cell wall regrows
- cell wall grows from inside to out to divide cell

animal
- centrioles always present
- no cell wall
- cell surface membrane pulled into divide cell

Question 17

how do you calculate mitotic index

Answer 17

no of cells in mitosis/total no of cells

Question 18

what happens during prophase 1

Answer 18

DNA coils to form chromosomes
nuclear membrane breaks down
centrioles move to poles of cell producing spindle fibres
homologous chromosomes pair up and form bivalent pairs

Question 19

what happens during metaphase 1

Answer 19

bivalents line up along equator
centromere attaches to spindle fibres
independent segregation takes place

Question 20

what happens during anaphase 1

Answer 20

spindle fibres contract
homologous chromosomes separate and are pulled to opposite poles of the cell

Question 21

what happens during telophase 1

Answer 21

chromosomes uncoil
nuclear membrane reforms
nucleus reappears

Question 22

what happens during prophase 2

Answer 22

DNA coils up to form chromosomes
nuclear membrane breaks down
centrioles move to opposite poles of cell producing spindle fibres at 90 degrees to prev division

Question 23

what happens during metaphase 2

Answer 23

chromosomes align at the equator
centromere attaches to spindle fibres

Question 24

what happens during anaphase 2

Answer 24

spindle fibres contract
centromere splits, chromatids separate
chromatids are pulled to opposite poles

Question 25

what happens during telophase 2

Answer 25

DNA uncoils, nuclear membrane regrows nucleus reforms

Question 26

what is independent segregation

Answer 26

refers to the random separation of homologous chromosomes during meiosis I. This process contributes to genetic variation by producing different combinations of alleles in the resulting daughter cells

Question 27

how do you calculate the number of possible gametes

Answer 27

2^n - where n is the chromosome number

Question 28

what is crossing over

Answer 28

during metaphase 1, non sister chromatids wrap around each other, chiasma forms, DNA is exchanged between chromatids

Question 29

what are the adaptations of an erythrocyte

Answer 29

biconcave disc - larger SA:V haemoglobin - binds to 02 easily no nucleus flexible membrane - can squeeze through narrow capillaries

Question 30

what are the adaptations of a neutrophil

Answer 30

granular cytoplasm - contains many lysosomes (digestive enzymes) multilobulated nucleus - can fit through capillary gaps and reach infection

Question 31

what are the adaptations of a sperm cell

Answer 31

many mitochondria acrosome haploid nucleus flagellum

Question 32

what are the adaptations of guard cells

Answer 32

cell wall thicker on inside so volume change doesnt change shape of cell symmetrically

Question 33

what are the adaptations of a palisade cell

Answer 33

many chloroplasts tall and thin - can be densely packed together vacuole - pushes chloroplasts to outer part of cell thinner cell wall

Question 34

what are the adaptations of a root hair cell

Answer 34

long extension - increases SA:V many mitochondria thinner cell walls

Question 35

what are the adaptations of a xylem

Answer 35

lignin - provides structural support

Question 36

what are the adaptations of phloem

Answer 36

sieve plates - allow easy flow of nutrients

Question 37

give examples of epithelial tissue

Answer 37

squamous (blood vessels + alveoli) columnar (digestive tract) ciliated (respiratory tract)

Question 38

what is the purpose of epithelial tissue

Answer 38

covers body surfaces (acts as a barrier) and facilitates diffusion

Question 39

what is the purpose of connective tissue

Answer 39

provides structural support to other tissues and acts as a transport medium

Question 40

give examples of connective tissue

Answer 40

cartilage

Question 41

what are the 3 types of muscle tissue

Answer 41

skeletal smooth cardiac

Question 42

what is the purpose of nervous tissue

Answer 42

transmits electrical signals

Question 43

what is epidermal tissue

Answer 43

outer protective layer of plant covered by waxy cuticle

Question 44

what is the purpose of ground tissue

Answer 44

storage of food and water, provides structural support

Question 45

give an example of ground tissue

Answer 45

mesophyll

Question 46

give examples of vascular tissue

Answer 46

xylem and phloem

Question 47

what are totipotent stem cells

Answer 47

can divide and produce any type of body cell (only occur in very early mammalian embryos)

Question 48

what are pluripotent stem cells

Answer 48

can differentiate to wide range of cell types in unlimited numbers and can be used to treat human disorders

Question 49

what are multipotent stem cells

Answer 49

can divide to form a limited number of different cell types

Question 50

what are unipotent stem cells

Answer 50

can only divide to one type of cell eg cardiomyocytes

Question 51

what are induced pluripotent stem cells

Answer 51

produced from adult somatic cells using appropriate protein transcription factors

Question 52

what are transcription factors

Answer 52

chemicals that bind to DNA and stimulate/inhibit transcription/RNA polymerase

Question 53

give the potential medical uses of stem cells for damaged tissues

Answer 53

macular degeneration cardiovascular disease diabetes type1

Question 54

give the potential medical uses of stem cells for neurological conditions

Answer 54

parkinson's alzheimer's

Question 55

give the potential research uses of stem cells for developmental biology

Answer 55

how cells specialise embryo development

Question 56

what are the sources of stem cells and what potency do they produce

Answer 56

bone marrow (multi) umbilical cord (multi) aborted/ still born foetuses (pluri) spare embryos from IVF (pluri) meristem

Question 57

what are the ethical concerns with stem cells

Answer 57

embryos - right to life and informed consent