Topic 2- Cells And Control

Question 1

What are the stages of mitosis?

Answer 1

• Interphase
• prophase
• metaphase
• anaphase
• telophase

Question 2

explain interphase

Answer 2

The DNA in chromosomes copies itself ready for mitosis.

The cell spends most of its life in this phase.

Question 3

explain prophase

Answer 3

The DNA in chromosomes and their copies condenses to become more visible.

The membrane around the nucleus disappears.

Question 4

explain metaphase

Answer 4

Chromosomes and their copies line up in the middle of the cell.

Question 5

explain anaphase

Answer 5

Chromosomes and their copies are pulled to different ends of the cell.

Question 6

explain telophase

Answer 6

New membranes form around the chromosomes at each end of the cell.

Question 7

definition of mitosis

Answer 7

• Mitosis is a type of cell division
• where a diploid body cell copies itself and finally divides into two identical diploid daughter cells.
• The daughter cells are clones of each other

Question 8

definition of cell differention

Answer 8

When cells express specific genes that characterise a certain type of cell

Eg.blood cells

Question 9

definition of cell division

Answer 9

mitosis causes cells to divide

Question 10

definition of cell elongation

Answer 10

Where a plant cell expands, making the cel bigger and making the plant grow

Question 11

what is cancer?

Answer 11

Out of control mitosis where the cells don’t stop dividing

Question 12

definition of meristems

Answer 12

Meristems are regions of unspecialised cells in plants that are capable of cell division.

Meristems make unspecialised cells that have the potential to become any type of specialised cell.

Question 13

how can stem cells be used in medicine?

Answer 13

•to cure diseases
(Eg. Sickle cell anaemia, cured with a bone marrow transplant)

•to create specialised cells to replace damaged ones

Question 14

definition of stem cells

Answer 14

Stem cells are cells that have not undergone differentiation.

A cell which has not yet become specialised is called undifferentiated.

Question 15

what is the function of the cerebrum?

Answer 15

• Controls muscles

* the right side of the cerebrum controls muscles on the left side of the body and vice versa

Question 16

what is the function of the cerebellum?

Answer 16

Responsible for muscle coordination and balance

Question 17

what is the function of the medulla oblongata?

Answer 17

Controls unconscious activities such as breathing and your heart rate

Question 18

what is a CT scan?

Answer 18

1) A CT scanner uses X-rays to produce an image of the brain.
2) A CT scan main structures the brain, but it doesn’t show the functions of them.

3) However, if a CT scan shows a diseased or damaged brain structure and the patient has lost some function, the function of that part of the brain can be worked out.
For example, if an area of the brain is damaged and the patient can’t see, then that area is involved in vision.

Question 19

What is a PET scan?

Answer 19

1) They use radioactive chemicals to show which parts of the brain are active when the person is inside the scanner.
2) PET scans are very detailed and can be used to investigate both the structure and the function of the brain in real time.

3) PET scans can show if areas in the brain are unusually inactive or active, so they are useful for studuing disorders that change the brain’s activity.
E.g. in Alzheimer’s disease, activity in certain areas of the brain is reduced PET scans show this reduction when compared to normal brain.

Question 20

what is a sensory neurone?

Answer 20

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

Question 21

what is a motor neurone?

Answer 21

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

Question 22

what is a relay neurone?

Answer 22

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

Question 23

definition of synapse

Answer 23

• Where two neurones meet there is a tiny gap called a synapse
• Information crosses this gap using neurotransmitters

Question 24

definition of iris

Answer 24

The iris controls how much light enters the pupil

Question 25

definition of lens

Answer 25

The lens refracts light, focusing it into the retina

Question 26

definition of retina

Answer 26

The retina is the light sensitive part and it’s covered in receptor cells called rods and cones which detect light

Question 27

definition of rods

Answer 27

Rods are more sensitive in dim light but can’t sense colour

Question 28

definition of cones

Answer 28

Cones are sensitive to different colours

Question 29

definition of optic nerve

Answer 29

The optic nerve carries impulses from the receptors to the brain

Question 30

definition of long sighted

Answer 30

• long-sighted people are unable to focus on near objects
• This occurs when the lens is the wrong shape and doesn’t bend the light enough or the eyeball is too short.
• Light from near objects is brought into focus behind the retina.
• You can use glasses or contact lenses with a convex lens to correct

Question 31

definition of short sighted

Answer 31

• Short-sighted people are unable to focus on distant objects
• This occurs when the lens is the wrong shape and bends the light too much or the eyeball is too long.
• Light from distant objects is brought into focus in front of the retina
• You can use glasses or contact lenses with a concave lens to correct it.