Cells and Control

Question 1

Which phase does a cell stay for the longest during mitosis?

Answer 1

Interphase

Question 2

What are the stages of mitosis, in order?

Answer 2

Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis

Question 3

Where does mitosis happen?

Answer 3

In any cells apart from gametes (sex cells)

Question 4

What is the name of the cell that divides and its divided products?

Answer 4

Parent cell, daughter cells (which are identical to the parent cell)

Question 5

What happens in the interphase?

Answer 5

• DNA of chromosome duplicates to form 2 chromatids

- Chromosomes now condensed and visible

Question 6

What happens in the prophase?

Answer 6

• Nuclear membrane starts to disappear

- Spindle fibres appear

Question 7

What happens in the metaphase?

Answer 7

• Chromosomes line up on spindle fibres on equator

- Nuclear membrane now completely gone

Question 8

What happens in the anaphase?

Answer 8

• Chromatids are separated as are pulled to opposite poles of cell on spindle fibres
• Each pole now a chromosome

Question 9

What happens in the telophase?

Answer 9

-Membrane forms around each set of chromosomes to form nuclei

Question 10

What happens in cytokinesis?

Answer 10

• Cytoplasm of cell is separated as cell membranes form around each of them into 2 daughter cells
• Cell walls form in plant cells

Question 11

What is an anagram to remember the stages of mitosis?

Answer 11

I
Promised
My
Aunt
To
Camp

Question 12

What is the name of the group of cells (plant tissue) near the end of each shoot and roots which allow plants to continue growing throughout their lives?

Answer 12

Meristems

Question 13

What is differentiation?

Answer 13

The process in which changes less specialised cells into more specialised ones to perform a particular function

Question 14

What is the function of a xylem vessel?

Answer 14

It carries water and dissolved mineral salts up the plant

Question 15

How is a root hair cell different from other types of root cell and how is it adapted to its function?

Answer 15

It has a long extension into the soil; this increases the surface area, which helps absorb water and mineral salts

Question 16

How is the palisade cell adapted to its function?

Answer 16

• It has many more chloroplasts in it than other cells, as they are the main site of photosynthesis
• Have vacuoles that restrict the chloroplasts to remain on a layer near the outside of the cell where they can be reached by light more easily for photosynthesis

Question 17

What is mitosis used for?

Answer 17

Growth, repair and asexual reproduction

Question 18

What happens if cells divide uncontrollably from mitosis?

Answer 18

They form a lump of cells called a tumour, which is worse if these are cancer cells

Question 19

How do plant cells grow by enlarging after mitosis?

Answer 19

Young plant cells have small vacuoles which take in water by osmosis and enlarge

Question 20

How is the growth of babies checked by percentile charts?

Answer 20

By measuring their length/height, head circumference and their weight

Question 21

What are stem cells?

Answer 21

Unspecialised cells that can develop into any type of cell, such as early embryos

Question 22

What happens after the 8 cell stage in embryonic stem cells?

Answer 22

Most of the embryonic cells become specialised and can no longer differentiate. Some will become never, blood, muscle, bone cells, etc

Question 23

What is the difference between adult stem cells and embryonic stem cells?

Answer 23

Adult stem cells can only make a small number of cell types

Question 24

What are some uses of embryonic stem cells?

Answer 24

• Replacing or repairing brain cells to treat people with Parkinson’s disease
• Replacing damaged cells in the retina in the eye to treat some kinds of blindness
• Growing new tissues in the lab to use for transplants or drug testing

Question 25

What are some uses of adult stem cells?

Answer 25

- Treatment of leukaemia | - Potentially growing new tissues to match to the patient

Question 26

What are advantages and disadvantages of using embryonic stem cells?

Answer 26

-Easy to extract and produces most types of cells BUT -Embryo is destroyed when cells are removed and so some think they have a right to live (unethical)

Question 27

What are advantages and disadvantages of using adult stem cells?

Answer 27

-No embryo destroyed (not ethical issue) and if taken from the person to be treated, will not cause rejection by the body BUT -Only produces a few types of cell

Question 28

What are advantages and disadvantages of all stem cells?

Answer 28

-Replaces faulty cells with healthy cells so person is well again BUT -There is a risk as some stem cells may not stop dividing, and so cause cancer from tumours

Question 29

What are neurones and what do they do?

Answer 29

Nerve cells - process information and control the body

Question 30

What is the cerebral cortex?

Answer 30

- Makes up 80% of the brain (the most important part) - Controls and processes body and information - Controls personality, our senses, language memory, behaviour and consciousness

Question 31

What does the cerebellum control?

Answer 31

Balance and posture

Question 32

What is the medulla oblongata?

Answer 32

Controls your heart rate, your breathing rate and reflexes such as vomiting, swallowing and sneezing

Question 33

What does the medulla oblongata connect?

Answer 33

The brain to the spinal cord

Question 34

How does a CT scan to develop an image of the structures in the brain work?

Answer 34

- X-ray beam moves in a circle around the head - Detectors measure the absorption of the X-rays - Computer uses this info to build up a view of the inside of the body as a series of 'slices'

Question 35

What does damage to the spinal cord do?

Answer 35

Reduces the flow of info between the brain and parts of the body

Question 36

Why can't stem cells be used to repair the damage caused by a spinal injury?

Answer 36

There are no adult stem cells that can differentiate into neurones in the spinal cord, and so new neurones can't be made to repair the damage

Question 37

How can you remove a tumour?

Answer 37

Cut it out or the cells can be killed using radiotherapy and chemo

Question 38

What does the central nervous system (CNS) do?

Answer 38

Control your body using electrical signals called impulses

Question 39

What are the organs in the CNS?

Answer 39

The brain, the spinal cord and sensory organs

Question 40

What is a stimulus?

Answer 40

Anything your body is sensitive to, including changes in your body and in your surroundings

Question 41

What do receptor cells do?

Answer 41

Detect stimuli

Question 42

What is neurotransmission?

Answer 42

The travelling or transmission of impulse; it happens in neurones (nerve cells)

Question 43

What are effectors?

Answer 43

Things that carry out actions, such as muscles and glands (eg. sweat glands)

Question 44

What do synapses do to the speed of neurotransmission?

Answer 44

Slow it down; synapses is the point where 2 neurones meet

Question 45

What are reflex actions?

Answer 45

Responses that are automatic, extremely quick and protect the body

Question 46

What do reflex arcs do?

Answer 46

They bypass the parts of the brain involved in processing info and so are quicker than responses that need processing

Question 47

What are neurones?

Answer 47

Specialised cells that carry nervous impulses

Question 48

What are the 3 main types of neurones?

Answer 48

Sensory, motor and relay

Question 49

What are the 3 main structures in a neurone?

Answer 49

Axon, dendrite and myelin sheath

Question 50

What is the function of the axon?

Answer 50

Carries impulses away from the cell body

Question 51

What is the function of the dendrite?

Answer 51

Receives impulses from other neurones

Question 52

What is the function of the myelin sheath?

Answer 52

It is a fatty layer that provides electrical insulation around the neurone

Question 53

What do sensory neurones do?

Answer 53

They carry impulses from receptors to the CNS

Question 54

What is the eye?

Answer 54

A sensory receptor that detects light and sends impulses along sensory neurones to the brain

Question 55

What do the cornea and the lens do?

Answer 55

They focus the light to form a sharp image on the retina

Question 56

What does the retina contain that helps it detect light and form an image?

Answer 56

Receptor cells called rods and cones

Question 57

What does the iris do?

Answer 57

It is a ring of muscle that controls the size of the pupil

Question 58

What does your eye do when you focus on a near object?

Answer 58

- Ciliary muscle contract - Suspensory ligaments become slack - Lens becomes rounded - Image focused on the retina

Question 59

When do cataracts occur?

Answer 59

When the lens goes cloudy (opacity = cloud formation); as a result, light can't get through it properly

Question 60

What happens in colour blindness?

Answer 60

Normal eye - 3 types of cone cell that detects red, green and blue light Colour blindness - when at least 1 type of cone cell is missing or does not work properly

Question 61

Describe the steps of laser eye surgery

Answer 61

- Anesthetic drop on eye - Create flap - Laser reshapes - Close flap - Eye heals itself

Question 62

What is astigmatism?

Answer 62

Usually caused by an imperfectly shaped cornea which causes the light to be refracted by different amounts in different planes