Topic B2

Question 1

Cell cycle

Answer 1

A series of stages in which cells divide to produce new cells

Question 2

What is a cell in when it is not dividing?

Answer 2

Interphase

Question 3

What does a cell do before it is dividing?

Answer 3

-copy some of its subcellular structures
-Make a copy of its DNA

Question 4

Mitosis

Answer 4

Stage of a cell cycle when the cell divides

Question 5

Prophase

Answer 5

1st stage
Membrane around nucleus breaks down

Question 6

Metaphase

Answer 6

2nd stage
Chromosomes lineup at the centre of the cell

Question 7

Anaphase

Answer 7

3rd stage
Chromosomes split in half
-Each half pulled to opposite ends of the cell

Question 8

Telephase

Answer 8

4th stage
Membranes form around chromosomes

Question 9

Cytokinesis

Answer 9

5th stage
Cytoplasm and cell membranes divide into 2 daughter cells

Question 10

What does mitosis allow?

Answer 10

Organisms to grow or replace cells that have been damaged

Question 11

Where is mitosis sometimes used?

Answer 11

Asexual reproduction

Question 12

Plants and animals methods of growth

Answer 12

-Cell differentiation (when a cell changes to become specialised for its job)
-Cell division
-Cell elongation

Question 13

What are percentile charts used for?

Answer 13

-Monitor a child’s growth (Mass length and head size)

Question 14

What does the 50th percentile mean?

Answer 14

The size 50% of babies will have reached at certain age

Question 15

When my doctors be concerned over a percentile chart?

Answer 15

If a baby size is below the 0.4th percentile or changed by more than 2 percentile lines over time

Question 16

Stem cells

Answer 16

Undifferentiated cells that can divide to produce lots more stem cells and can differentiate into many other types of cell

Question 17

Adult animal stem cells can become..

Answer 17

Many kind of cell

Question 18

Human embryo stem cells can become..

Answer 18

Any kind of human cell

Question 19

Plant meristem stem cells can become..

Answer 19

Any kind of plant cell

Question 20

Where can stem cells be grown?

Answer 20

In a lab

Question 21

What can be done with specialised cells?

Answer 21

-Transferred into people
-Used in medicine

Question 22

Benefits of stem cells

Answer 22

Could replace cells that could have been damaged e.g. new heart muscle cells could treat heart disease

Question 23

Risks of stem cells

Answer 23

-Tumours
-Disease
-Rejection by immune system

Question 24

Neurones

Answer 24

Cells that carry information as electrical impulses in the nervous system

Question 25

What does the nervous system allow?

Answer 25

Humans can react to their surroundings and coordinate their behaviour

Question 26

What does the CNS consist of

Answer 26

Brain and spinal cord

Question 27

Order of nervous system

Answer 27

1. Stimulus
2. Sensory receptor
3. Sensory neurone
4. CNS
5. Motor neurone
   6. Effector (muscles or glands)
6. Response

Question 28

Sensory neurone

Answer 28

Carries impulses from receptor cells to the CNS

Question 29

Motor neurone

Answer 29

Carries impulses from the CNS to effector cells

Question 30

Relay neurone

Answer 30

sensory neurones>motor neurones

Question 31

What does the myelin sheath do?

Answer 31

Speeds up the electrical impulse

Question 32

Synapse

Answer 32

The connection between 2 neurones 

Question 33

What happens in a synapse?

Answer 33

An electrical impulse is transferred across it by neurotransmitters moving across the gap

Question 34

Reflexes

Answer 34

Rapid, automatic responses that don’t involve the conscious part of the brain. They can reduce the chance of injury.

Question 35

Reflex arc

Answer 35

The passage of information reflex, from receptor to effector 

Question 36

The five steps in a reflex arc

Answer 36

1.Simulation of receptor
2.Impulses travel along sensory neurone>relay neurone>motor neurone
5.Effector responds