Topic 2 - Cells And Control

Question 1

What is the interphase of the cell cycle?

Answer 1

When the cell is not dividing. The cell is growing and increasing the number of subcellular structures, such as mitochondria.

Question 2

What is the prophase stage of the cell cycle?

Answer 2

The chromosomes of the cell condense. The membrane of the nucleus breaks down, and the chromosomes move freely in the cytoplasm.

Question 3

What is the metaphase stage of the cell cycle?

Answer 3

The chromosomes line up at the centre of the cell

Question 4

What is the Anaphase stage of the cell cycle?

Answer 4

Cell fibres pull the cell apart. The two arms of each chromosome go to opposite ends of the cell.

Question 5

What is the Telophase of the cell cycle?

Answer 5

Membranes form around each of the sets of chromosomes. These become the nuclei of the two new cells.

Question 6

What is cytokinesis?

Answer 6

When the cytoplasm and cell membrane of a cell divides to form two separate cells.

Question 7

What is cell differentiation?

Answer 7

The process of a cell changing to become specialised for its job.

Question 8

What is the difference between a cancer and a tumour?

Answer 8

Cancer invades other parts of the body while a tumour does not

Question 9

What are stem cells?

Answer 9

Cells that that have yet to differentiate into specialised cells.

Question 10

When are Stem cells found?

Answer 10

Embryos and bone marrow.

Question 11

What are 3 risks of using stem cells in medicine?

Answer 11

Tumour development - stem cells rapidly divide, increasing the chance if a tumour developing.
Disease transmission - viruses inside the cells could be transmitted to the patient
Rejection - the body may recognise the cells as foreign and reject them. Triggering an immune response.

Question 12

What does the right cerebral hemisphere control?

Answer 12

Controls the muscles on the left side of the body.

Question 13

What does the left cerebral control?

Answer 13

The muscles on the right side of the body.

Question 14

What are the different parts of the cerebrum responsible for?

Answer 14

Movement, intelligence, memory, language and vision

Question 15

What is the cerebellum responsible for?

Answer 15

Muscle coordination and balance

Question 16

What is th Medulla oblongata responsible for?

Answer 16

Unconscious activities such as breathing

Question 17

Describe the structure of a sensory neurone

Answer 17

One long dendron, located in the middle of the neurone, carries nerve impulses from receptor cells to the cell body. One short axon carries nerve impulses from the cell body to the CNS.

Question 18

Describe the motor neurone

Answer 18

Many short dendrites carry nerve impulses from the CNS to the cell body. One long axon carries nerve impulses from the cell body to the effector cells.

Question 19

Describe the relay neurone

Answer 19

Many short dendrites carry nerve impulses from the sensory neurones to the cell body. An axon carries nerve impulses from the cell body to the motor neurones.

Question 20

What do dendrites and dendrons do in neurones?

Answer 20

Carry nerve impulses towards the body

Question 21

What do axons do in neurones?

Answer 21

Carry nerve impulses away from the body

Question 22

What does the myelin sheath do in neurones?

Answer 22

Acts as an electrical insulator, speeding up the electrical impulse

Question 23

Wheres is the CNS(central nervous system located)

Answer 23

From the base of the brain down to the bottom of the spine.

Question 24

What do synapses do and how do they work?

Answer 24

They are the connection between to neurones. The nerve signal is transferred by chemicals, called neurotransmitters, that diffuse across the gap between the two neurones. The neurotransmitters then set off an electrical transmitter to the next neurone.

Question 25

What is a reflex?

Answer 25

A automatic, rapid response to stimuli

Question 26

How do reflexes work?

Answer 26

First there is a stimulation in the pain receptors. An impulse is sent along a sensory neurone to a relay neurone in the CNS. The impulse then travels from the CNS along the a motor neurone to a muscle or gland.

Question 27

What is the passage of information in a reflex called?

Answer 27

A reflex arc

Question 28

How does the reflex to protect your eye from bright light work?

Answer 28

Light receptors in the eye detect the light and send a message along the sensory neurone. The message travels along a relay neurone to a motor neurone which tells the muscles in the iris to contract, making the pupil smaller.

Question 29

What does the cornea in the eye do?

Answer 29

Refract the light into the eys

Question 30

What does the iris in the eye do?

Answer 30

Control how much light enters the eye

Question 31

What does the lens in the eye do?

Answer 31

Refract the light, focusing it on the retina.

Question 32

What does the retina in the eye do?

Answer 32

It is the light sensitive part, it is covered in rods and cones which detect the light.

Question 33

What do rods in the eye do?

Answer 33

They are sensitive to dim light, but can't sense colour.

Question 34

What do cones in the eye do?

Answer 34

Sensitive to colour, but don't work well in dim light

Question 35

What does the optic nerve do?

Answer 35

Carry electrical impulses from the eye to the brain

Question 36

What is a myelinated neurone?

Answer 36

A neurone with a myelin sheath

Question 37

What is a unmylinated neurone?

Answer 37

A neurone without a myelin sheath

Question 38

What do meristems do?

Answer 38

Produce unspecialised plant cells that divide to produce any specialised cell in the plant.

Question 39

What is special about how meristems reproduce?

Answer 39

They are the only cell in the plant that reproduces through mitosis

Question 40

Where are meristems found?

Answer 40

In the areas where the plant is growing

Question 41

What does a CT Scanner show and how does it work?

Answer 41

A CT scanner use X-Rays to produce an image of the brain. A CT scan shows the main structure of the brain but not the function of them.

Question 42

What does a PET Scanner show and how does it work?

Answer 42

They show both the structure and the function of the brain in real time. They use radioactive chemicals to show which part if the brain are active.

Question 43

State three reasons why it is hard to fix problems in the brain and spinal cord

Answer 43

Neurones in the CNS do not repair themselves and there is not currently way to repair them artificially There are parts of the CNS that are hard/impossible to access without damaging the brain Treatment for problems in the CNS may lead to permanent damage.