Cells and control - topic 2 (pg 13-19) paper 1

Question 1

two types of cell division

Answer 1

mitosis and meiosis

Question 2

mitosis happens in

Answer 2

body cells excluding gametes

Question 3

dividing cell is called

Answer 3

parent cell

Question 4

new cells formed are called

Answer 4

daughter cells; identical to parent cell

Question 5

mitosis makes

Answer 5

two new cells

genetically identical cells

Question 6

diploid means

Answer 6

double (two sets of) chromosomes

Question 7

Stages of mitosis

Answer 7

IPMAT
Interphase - chromosomes become visible, DNA has been copied
Prophase - each chromosome consists of two chromatids which condense, spindle fibre forms
Metaphase - nuclear membrane breaks down, chromosomes line up in the middle of the cell
Anaphase - chromatids are pulled to each pole of the cell, now called chromosomes
Telophase - spindle fibres disappear, nuclear membrane forms around chromosomes
Cytokinesis - cell splits in two

Question 8

mitosis is used for

Answer 8

growth
repair
asexual reproduction

Question 9

after growth

Answer 9

cells can differentiate into specialised cells

Question 10

cancer cells are

Answer 10

abnormal cells that divide uncontrollably

Question 11

specialised cell

Answer 11

cells adapted to carry out a particular function

Question 12

growth in animals

Answer 12

a zygote, or fertilised egg cell, divides by mitotic producing daughter cells which grow and differentiate

Question 13

growth in plants

Answer 13

plant cells divide by mitosis, behind tips of roots and shoots, cells enlarge, by taking water in vacuoles by osmosis, cell elongates, can then differentiate

Question 14

examples of specialised animal cells

Answer 14

red blood cells
egg and sperm cells
nerve cell
bone cells

Question 15

example of specialised plant cells

Answer 15

xylem
phloem
root hair cells
stoma cells

Question 16

Growth is a

Answer 16

permanent increase in size

Question 17

Percentile charts

Answer 17

help to show if a baby is growing correctly, slower or faster
above the 95th or below 5th percentile may be not be growing correctly
baby who’s mass decreases by 2 or more percentiles in the first year may not be growing correctly

Question 18

stem cells

Answer 18

can divide to produce many types of cell

replace faulty cells
may not stop dividing causing cancer

Question 19

embryonic stem cells

Answer 19

taken from embryos at an early stage of division

repairing brain cells to treat Parkinson’s
replace damaged retina cells, treat blindness

easy to extract, produce any cell
ethical issues of destroying embryos

Question 20

adult stem cells

Answer 20

found differentiated tissue, bone or skin - divide to replace damaged cells

treatment of leukaemiapotentially grow new tissue genetically matched to patient

no embryo destroyed, will not cause rejection
produce only s few types of cell

Question 21

Meristems

Answer 21

Plants, found in rapidly growing parts of the plant, divide to produce and plant cell

Question 22

Sensory neurone

Answer 22

carry impulses to central nervous system (CNS)

• Dendron- carries impulse towards cell body
• axon- carries impulses away from cell body
• fatty myelin sheath- insulates neuron

Question 23

Motor neurone

Answer 23

carry impulses from CNS to effector organs

• axon- carries electrical impulse over long distance
• nerve ending- transmits impulse to effector, muscle
• electrical impulse jumps gap in myelin sheath, speeding up rate of transmission

Question 24

Synapses

Answer 24

where two neurones meet, gap in-between

1) electrical nerve impulse reaches end of axon
2) electrical impulse causes chemical neurotransmitter to be released from vesicles into the gap
3) neurotransmitter diffuses across gap and fits into receptors, causing a new impulse in next neurone

Question 25

Reflex arcs

Answer 25

involve 3 neurones, provide fast reactions without involving the brain. Reflex arcs are:
- immediate
- involuntary
- innate
- invariable
protect from immediate harm e.g. eye blink