Cells and Control -

Question 1

What is the cell cycle?

Answer 1

A cycle that most cells go through in order to replicate.

Question 2

What are the 3 main stages of the cell cycle?

Answer 2

1. Growth and replication of organelles (interphase)
2. DNA replication (interphase)
3. Mitosis

Question 3

What happens during the prophase?

Answer 3

• the nuclear envelope begins to break down
• spindle fibres appear
• chromosomes become visible (they condense)

Question 4

What happens during the metaphase?

Answer 4

• chromosomes line up at the equator of the cell
• spindle fibres attach themselves to these chromosomes at the equator

Question 5

What happens during the anaphase?

Answer 5

• chromosomes break at the equator of the cell
• sister chromatids move to opposite ends with the spindle fibres still attached.

Question 6

What happens during the telophase?

Answer 6

• nuclei membranes forms around the two chromosomes
• spindle fibres break down
• cytoplasm begins dividing

Question 7

What happens during cytokinesis?

Answer 7

• cell surface membrane forms to separate two genetically identical cells
• (in plant cells) the cell wall begins to form.

Question 8

What is growth?

Answer 8

a permeant increase in mass, size and length.

Question 9

Why is it beneficial to have lots of cells?

Answer 9

So that these cells can be used for a specialised function.

Question 10

What is differentiation?

Answer 10

The process of which stem cells become specialised cells.

Question 11

Describe one feature of a fat cell.

Answer 11

It has fat droplets.

Question 12

What are the advantages of using the meristem in plants?

Answer 12

1. to produce rare plants
2. to produce exotic plants
3. for food production

Question 13

What disadvantages does using stem cell treatment bring?

Answer 13

1. it may be unethical for some people
2. it can carry viruses
3. if the cell is defected, it will pass on this defect
4. if the cell division is uncontrollable - it could cause tumours which may be cancerous.
5. unknown effects on the body
6. it could be rejected from the patient’s body
7. cells could differentiate into the wrong type of cell

Question 14

What are the two parts of the nervous system and what do they consist of?

Answer 14

CNS (Central Nervous System) - The brain and the spinal chord

PNS - (Peripheral Nervous System) - All other nerves

Question 15

What do ears sense?

Answer 15

Sound and position of head.

Question 16

What does the tongue sense?

Answer 16

Chemicals in food.

Question 17

What does the nose sense?

Answer 17

Chemicals in the air.

Question 18

What do the eyes sense?

Answer 18

Light.

Question 19

What does the skin sense?

Answer 19

temperature, touch, pressure and pain.

Question 20

In what order is the Nervous System triggered?

Answer 20

stimulus –> receptor cells –> sensory neuron –> relay neuron –> motor neuron –> effector –> response.

Question 21

Name two different types of effectors.

Answer 21

Muscles and glands.

Question 22

Why is the myelin sheath useful?

Answer 22

It insulates the impulses which allow them to jump along the cell which speeds up the transmission.

Question 23

How does a CT scan work?

Answer 23

It uses X-Rays. The affected part of the brain will absorb more X-Rays than the non-affected areas.

Question 24

How does a PET scan work?

Answer 24

The patient ingests or is injected with a radioactive tracer like glucose. The machinery detects the gamma rays the radioactive tracer produces. The affected area of the brain will have a larger amount of ongoing chemical reactions than the non-affected areas.

Question 25

What do Circular Muscles do?

Answer 25

They contract in bright light to constrict the pupil.

Question 26

What do Radial Muscles do?

Answer 26

They contact in dim light to dilate the pupil.