Section 2 - Cells And Control

Question 1

Why do enzymes break down molecules

Answer 1

Many molecules of the food are too big to be passed through the walls of the digestive system. This means the digestive enzymes have to break them down into more soluble and smaller molecules. These then can pass easily through the walls of the digestive system and to be absorbed into the bloodstream. They can pass into cells and be used by the body.

Question 2

Function of enzymes

Answer 2

• they have special shapes so they can 𝘾𝙖𝙩𝙖𝙡𝙮𝙨𝙚 𝙧𝙚𝙖𝙘𝙩𝙞𝙤𝙣𝙨.
• 𝘽𝙧𝙚𝙖𝙠𝙨 𝙙𝙤𝙬𝙣 big molecules
• some enzymes can 𝙅𝙤𝙞𝙣 𝙢𝙤𝙡𝙚𝙘𝙪𝙡𝙚𝙨 𝙩𝙤𝙜𝙚𝙩𝙝𝙚𝙧.

Question 3

How do enzymes help plants?

Answer 3

Plants store energy in the form of starch- carbohydrates. When the plant needs energy, the enzymes break down the starch into smaller molecules- sugars. This can then be respired to transfer energy to be used by the cells

Question 4

______ converts carbohydrates into ________

Answer 4

1. Carbohydrases
2. Simple sugars

Question 5

What converts proteins into amino acids?

Answer 5

Proteases

Question 6

________ converts lipids into _________

Answer 6

1. Lipases
2. Glycerol and fatty acids

Question 7

What happens when lipids are broken down

Answer 7

The fatty acids will lower the pH of the solution they are in

Question 8

What are lipids

Answer 8

Fats and oils

Question 9

Why are proteins, lipids and carbohydrates important to be broken down

Answer 9

They can be used for growth and other life processes

Question 10

How can carbohydrates be synthesised

Answer 10

Joining simple sugars together

Question 11

Glycogen synthase

Answer 11

An enzyme that joins together lots of chains of glucose molecules to make glycogen which is a molecule used to store energy in animals

Question 12

How are proteins synthesised

Answer 12

Joining amino acids together and enzymes catalyse the reactions for this

Question 13

Diffusion

Answer 13

The net movement of particles from a higher concentration to a lower concentration down the concentration gradient

Question 14

Concentration gradient

Answer 14

If something moves from an area of a 𝙃𝙞𝙜𝙝 𝙘𝙤𝙣𝙘𝙚𝙣𝙩𝙧𝙖𝙩𝙞𝙤𝙣 to a 𝙇𝙤𝙬 𝙘𝙤𝙣𝙘𝙚𝙣𝙩𝙧𝙖𝙩𝙞𝙤𝙣, it is said that it moves 𝘿𝙤𝙬𝙣 the 𝘾𝙤𝙣𝙘𝙚𝙣𝙩𝙧𝙖𝙩𝙞𝙤𝙣 𝙜𝙧𝙖𝙙𝙞𝙚𝙣𝙩 if it’s from an area of 𝙇𝙤𝙬 to 𝙃𝙞𝙜𝙝, it is moving 𝙐𝙥 the 𝘾𝙤𝙣𝙘𝙚𝙣𝙩𝙧𝙖𝙩𝙞𝙤𝙣 𝙜𝙧𝙖𝙙𝙞𝙚𝙣𝙩

Question 15

Where does diffusion occur

Answer 15

It only happens in 𝙡𝙞𝙦𝙪𝙞𝙙𝙨 and 𝙜𝙖𝙨𝙚𝙨. This is because the 𝙥𝙖𝙧𝙩𝙞𝙘𝙡𝙚𝙨 in these substances are able to 𝙢𝙤𝙫𝙚 𝙛𝙧𝙚𝙚𝙡𝙮 𝙖𝙣𝙙 𝙧𝙖𝙣𝙙𝙤𝙢𝙡𝙮

Question 16

Osmosis

Answer 16

The net movement of water molecules from an area of 𝙝𝙞𝙜𝙝 𝙬𝙖𝙩𝙚𝙧 𝙘𝙤𝙣𝙘𝙚𝙣𝙩𝙧𝙖𝙩𝙞𝙤𝙣 to a 𝙡𝙤𝙬 𝙬𝙖𝙩𝙚𝙧 𝙘𝙤𝙣𝙘𝙚𝙣𝙩𝙧𝙖𝙩𝙞𝙤𝙣 through a 𝙨𝙚𝙢𝙞 𝙥𝙚𝙧𝙢𝙚𝙖𝙗𝙡𝙚 𝙢𝙚𝙢𝙗𝙧𝙖𝙣𝙚. Going 𝙙𝙤𝙬𝙣 the 𝙘𝙤𝙣𝙘𝙚𝙣𝙩𝙧𝙖𝙩𝙞𝙤𝙣 𝙜𝙧𝙖𝙙𝙞𝙚𝙣𝙩.

Question 17

What is a semi permeable (also known as partially permeable) membrane?

Answer 17

A membrane with very 𝙨𝙢𝙖𝙡𝙡 𝙝𝙤𝙡𝙚𝙨 in it. This is so only 𝙩𝙞𝙣𝙮 𝙢𝙤𝙡𝙚𝙘𝙪𝙡𝙚𝙨 like water can go through it and bigger molecules can’t.

Question 18

Which way does the water molecules travel through the membrane in osmosis

Answer 18

The water molecules usually travel both ways as the water molecules move about randomly all the time. However, because there are more water molecules on one side theres a steady net flow of water into the region with fewer water molecules

Question 19

Active transport

Answer 19

The movement of particles across a membrane from a 𝙡𝙤𝙬𝙚𝙧 𝙘𝙤𝙣𝙘𝙚𝙣𝙩𝙧𝙖𝙩𝙞𝙤𝙣 to a 𝙝𝙞𝙜𝙝 𝙘𝙤𝙣𝙘𝙚𝙣𝙩𝙧𝙖𝙩𝙞𝙤𝙣 𝙪𝙨𝙞𝙣𝙜 𝙚𝙣𝙚𝙧𝙜𝙮. This means it is a 𝙥𝙖𝙨𝙨𝙞𝙫𝙚 process as it uses energy 𝙩𝙧𝙖𝙣𝙨𝙛𝙚𝙧𝙧𝙚𝙙 𝙙𝙪𝙧𝙞𝙣𝙜 𝙧𝙚𝙨𝙥𝙞𝙧𝙖𝙩𝙞𝙤𝙣.

Question 20

How is active transport used in the digestive system

Answer 20

When there’s a high concentration of nutrients in the gut than the blood. The nutrients diffuse naturally into the blood. However, sometimes there is a lower concentration of nutrients in the gut than in the blood. Active transport allows nutrients to be taken into the blood even though the concentration gradient is the wrong way. This helps us stop starving

Question 21

What is the aim of investigating osmosis

Answer 21

You have to put 𝙥𝙤𝙩𝙖𝙩𝙤 𝙘𝙮𝙡𝙞𝙣𝙙𝙚𝙧𝙨 into different concentrations of 𝙨𝙪𝙘𝙧𝙤𝙨𝙚 𝙨𝙤𝙡𝙪𝙩𝙞𝙤𝙣𝙨 in order to see what 𝙚𝙛𝙛𝙚𝙘𝙩 different 𝙬𝙖𝙩𝙚𝙧 𝙘𝙤𝙣𝙘𝙚𝙣𝙩𝙧𝙖𝙩𝙞𝙤𝙣𝙨 have on them

Question 22

Steps of the osmosis practical

Answer 22

1. Prepare sucrose solutions of different concentrations from pure water to very concentrated
2. Cut a potato into 1c, in diameter from the same potato
3. Divide the cylinders into groups of 3 and use a mass balance to measure the mass of each group
4. Place one group in each solution and leave for at least 40 mins
5. Remove the cylinders and pat dry so it moves excess water from the surface and you will get an accurate measurement
6. Weigh each group again and record the result.
7. The sucrose solution is the only thing you will change in the experiment. The size of the potato must be kept the same or the results will be invalid

Question 23

How do you find the result of the osmosis investigation

Answer 23

Calculate the Percentage change in mass for each cylinder before and after.

New - original/ original x 100

You then plot a graph and analyse your result.
When the curve crosses the x-axis, that means the fluid inside the cylinders and the sucrose solution have the same water solution (isotonic)
the points below the x-axis, the water concentrating of the sucrose is lower than I’m the cylinders. This causes the sun lingers to lose water so the mass decreases

Question 24

The _______ the concentration of the sucrose solution, the __________ the ________________

Answer 24

1. Higher
2. Lower
3. Water concentration

Question 25

Mitosis

Answer 25

A 1 𝙨𝙩𝙖𝙜𝙚 process for 𝙖𝙨𝙚𝙭𝙪𝙖𝙡 reproduction in order to make 2 𝙜𝙚𝙣𝙚𝙩𝙞𝙘𝙖𝙡𝙡𝙮 𝙞𝙙𝙚𝙣𝙩𝙞𝙘𝙖l 𝙙𝙞𝙥𝙡𝙤𝙞𝙙 𝙙𝙖𝙪𝙜𝙝𝙩𝙚𝙧 cells.

Question 26

Stages of the cell cycle

Answer 26

1. Interphase: the DNA duplicates and is copied and formed into X-shaped chromosomes.
2. Prophase: The membrane around the nucleus breaks down and the chromosomes are free in the cytoplasm
3. Metaphase: The chromosomes line up in the centre of the cell.
4. Anaphase: The spindle fibres pull apart the chromosomes into the opposite side of the cells
5. Telophase: membranes form around each of the sets of chromosomes which becomes the nucleus of the 2 cells and the nucleus has divided
6. Cytokinesis: the cytoplasm and cell membrane divide and form two genetically identical separate daughter cells.

Question 27

How do you calculate the number of cells they’ll be after multiple divisions.

Answer 27

Number of cells : 2^n. ‘n’ is the number of cell divisions

Question 28

Growth

Answer 28

Growth involves:
-cell division
-differentiation
-elongation
It is an increase in size of mass, and plants and animals need to grow and develop due to:
- cell differentiation
- Cell division

Question 29

Cell differentiation

Answer 29

A process where a cell changes to become specialised for its job. This makes specialised cells which allows multicellular organisms to work more efficiently

Question 30

Cell division

Answer 30

When cells are divided to new cells which contain the same genetic information

Question 31

Cell Elongation

Answer 31

Plants grow by cell elongation. This is where a plant expands which makes the cell bigger and making the plant grow

Question 32

Growth in animals

Answer 32

All growth in animals are by 𝙘𝙚𝙡𝙡 𝙙𝙞𝙫𝙞𝙨𝙞𝙤𝙣. They usually grow while. They’re young and then reach full growth then stop growing. Cells divide at a 𝙛𝙖𝙨𝙩 𝙧𝙖𝙩𝙚 however once you’re an 𝙖𝙙𝙪𝙡𝙩, 𝙘𝙚𝙡𝙡𝙨 𝙙𝙞𝙫𝙞𝙙𝙚 to 𝙧𝙚𝙥𝙡𝙖𝙘𝙚 𝙙𝙖𝙢𝙖𝙜𝙚𝙙 𝙤𝙧 𝙤𝙡𝙙 𝙘𝙚𝙡𝙡𝙨 meaning 𝙘𝙚𝙡𝙡 𝙙𝙞𝙛𝙛𝙚𝙧𝙚𝙣𝙩𝙞𝙖𝙩𝙞𝙤𝙣 𝙞𝙨 𝙡𝙤𝙨𝙩 𝙖𝙩 𝙖𝙣 𝙚𝙖𝙧𝙡𝙮 𝙖𝙜𝙚

Question 33

Growth in plants

Answer 33

Growth in height is usually due to cell elongation and the cell division usually just happens in the tips of the roots.
Plants usually grow continuously so plants continue to differentiate to develop new parts- leaves and routes

Question 34

What is cancer

Answer 34

When there is a 𝙘𝙝𝙖𝙣𝙜𝙚 𝙞𝙣 𝙤𝙣𝙚 𝙤𝙛 𝙩𝙝𝙚 𝙜𝙚𝙣𝙚𝙨 𝙬𝙝𝙞𝙘𝙝 𝙘𝙤𝙣𝙩𝙧𝙤𝙡𝙨 𝙘𝙚𝙡𝙡 𝙙𝙞𝙫𝙞𝙨𝙞𝙤𝙣, this causes the 𝙘𝙚𝙡𝙡𝙨 𝙩𝙤 𝙙𝙞𝙫𝙞𝙙𝙚 𝙧𝙖𝙥𝙞𝙙𝙡𝙮 causing a mass of abnormal cells making a 𝙩𝙪𝙢𝙤𝙧. If the tumor 𝙞𝙣𝙫𝙖𝙙𝙚𝙨 𝙖𝙣𝙙 𝙙𝙚𝙨𝙩𝙧𝙤𝙮𝙨 the tissue surrounding it, it will be called 𝙘𝙖𝙣𝙘𝙚𝙧.

Question 35

Growth charts

Answer 35

Used to asses a child’s growth over time. This is in order for an overall pattern in development would be see. And any problems would be highlighted. This will be plotted into growth charts:
-length
-mass
-head circumference

Question 36

Stem cells

Answer 36

They can differentiate into any different types of cells. They are also called undifferentiated cells and depending on the instructions they’re given, stem cells can divide by mitosis to become new cells which then can differentiate

Question 37

Where are stem cells found in

Answer 37

Early human embryos

Question 38

Embryonic cells

Answer 38

Embryonic stem cells have the potential to divide and produce any kind of cell at all. If they are removed from the embryo, they will differentiate into any cell type

Question 39

Osmosis in animal cells

Answer 39

• Hypertonic
• Isotonic
• Hypotonic

Question 40

Hypertonic solution

Answer 40

• High concentration of solutes and a low concentration of free water. So water will move out of the solute into the free water because of osmosis, causing the red blood cell to crenelate (shrivel up)

Question 41

Isotonic solution

Answer 41

• Has an equal concentration of solutes to the solution inside a cell

Question 42

Hypotonic solution

Answer 42

• A hypotonic has a low concentration of solutes and a high concentration of free water, water will move into the solute because of osmosis causing the cell to burst

Question 43

Osmosis in plant cells

Answer 43

• Plasmolyzed
• Flaccid
• Turgid

Question 44

Plasmolyzed

Answer 44

Plant cells become Plasmolyzed when free water moves out of the cell down the concentration gradient into the surround hypertonic solution that has a lower free water concentration, causing the plant cell to crenelate

Question 45

Flaccid

Answer 45

Has an equal concentration of solutes to the solution inside the cell

Question 46

Turgid

Answer 46

When free water moves into the cell, down the concentration gradient because the surrounding hypotonic solution has higher concentration of free water than inside the cell causing the cell to burst

Question 47

Diffusion in plant cells

Answer 47

Simple covalent molecules like oxygen and carbon dioxide diffuse into and out of the cells.
Carbon dioxide diffuses into plant leaves through the stomata, down the concentration gradient from an area of high concentration to low concentration because carbon dioxide is being used in the palisade mesophyll cells

Question 48

Diffusion in animal cells

Answer 48

Simple covalent molecules like oxygen and carbon dioxide diffuse into and out of the cells. Oxygen diffuses into an Amoeba down the concentration gradient from an area of High concentration to an area of low concentration as oxygen is used in respiration so that energy can be released into the cell

Question 49

Active transport In plants

Answer 49

Minerals are absorbed into the root hair cell by active transport. They move from an area of low concentration to an area of Hugh concentration in the vacuole of the root hair cell passing through the cell membrane using energy and a carrier protein

Question 50

Active transport in animals

Answer 50

Glucose is absorbed from the small intestine into the capillaries via ciliated epithelial cells. The glucose moves from an area of low concentration to high concentration in the epithelial cell passing through the cell membrane via a carrier protein using energy

Question 51

Adult stem cells

Answer 51

• Ohio found in certain places like Bone marrow. They can only differentiate into limited stem cells - blood cells
• in animals, adult stem cells are used to replace damaged cells - new skin or blood cells

Question 52

Meristems

Answer 52

• plants grow through meristems, only way the cells in a plant grow.
• in plants, only cells that divide by mitosis are found in plant tissues called meristems
• meristem tissues is found in the areas of a plant that are growing- tips of the root and shoots.
• produce unspecialised that are able to divide and form any cell type in the plant, they act like embryonic cells, but these cells can divide and differentiate to generate any type of cell for as long as the plant lobes.
• unspecialised cells go on to form specialised tissues like xylem and phloem

Question 53

How can stem cells be used in medicine

Answer 53

1. Doctors use stem cells to cure some diseases
2. Extracting stem cells from very early human embryos and growing them. Under certain conditions the stem cells can be stimulated to differentiate into specialised cells
3. Use stem cells to create specialised cells to replace those which have been damaged by disease or injury.

Question 54

How is sickle cell anaemia cured

Answer 54

Bone marrow transplant containing stem cells which produce new blood cells

Question 55

Tumour development

Answer 55

Stem cells divide very quickly, scientists are unable to control the rate at which the transplanted cells divide inside a patient, a tumour may develop

Question 56

Disease transmission

Answer 56

• viruses live inside cells.
• if donor stem cells are infected with a virus and this isn’t picked, the virus could be passed on to the recipient making them sicker

Question 57

How does your body react to a stimulus

Answer 57

1. A receptor detects a stimulus which is a change in an environment,
2. When the receptor detects a stimulus, the information is converted to a nervous electrical impulse and sent along the sensory neutrons to the CNS.
3. The CNS coordinates the response and decided on what to do with the stimulus
4. The stimulus then travels through the CNS and along the relay neurone.
5. The CNS sends information to an effector (gland or muscle) along the motor neurone
6. An effector then responds accordingly- muscle contracts or gland releases hormones
7. Your reaction time is the time it takes for you to respond to a stimulus

Question 58

What is your nervous system made up of

Answer 58

Neurones (nerve cells( which go to all parts of the body)

Question 59

Receptors

Answer 59

Your body contains a lot of sensory neurones, which are group of cells that can detect a change in the environment

Question 60

Stimulus

Answer 60

A change in the environment

Question 61

Sensory neurone

Answer 61

Carries impulses from the receptor cell towards the CNS

Question 62

Response

Answer 62

The action that occurs due to a stimulus

Question 63

What is the CNS

Answer 63

Contains brain and the spinal cord
Controls the nervous system

Question 64

What are the extensions that the cell body of neurones connect to

Answer 64

dendrites and dendrons
- they carry nerve impulses towards the cell body.
Axons
- carry the nerve impulse away from the cell body

Question 65

Myelin sheaths

Answer 65

Some axons are covered in myelin sheaths which acts as an electrical insulator by speeding up the electrical impulse

Question 66

Long neurones

Answer 66

Some neurones can be very long
- speeds up the impulse so one long neurone is much quicker than lots of short neurones joined together

Question 67

Short neurones

Answer 67

Short neurones slow down the impulse as connecting with another neurone slows it down, one long neurones are better than lots of short neurones joined together

Question 68

Structure of sensory neurone

Answer 68

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

Question 69

Motor neurone structure

Answer 69

• many short dendrites that carry nerve impulses from cell body to CNS
• one long axon which is surrounded by myelin sheaths which support the impulse by moving fast and not going out of the axon. Axon carries nerve impulses from the cell body to the axon terminal
• Axon terminal carries the nerve impulses brought from the axon from the cell body to the effector cells.
  The direction of impulse is from left to right

Question 70

Structure of the relay motor neurone

Answer 70

• many short dendrites carry nerve impulses from sensory neurone to the cell body
• an axon carries nerve impulses from the cell body to motor neurones

Question 71

Function of sensory neurone

Answer 71

Carries the nerve impulses towards the CNS

Question 72

Function of motor neurones

Answer 72

Carries the nerve impulses away from the CNS

Question 73

Function of relay neurone

Answer 73

Carries nervous impulse within the CNS to a muscle or gland (effectors)

Question 74

Synapses

Answer 74

It is the connection of 2 neurones - connects neurones
- the nerve signals are transferred by chemicals called neurotransmitters which diffuse across the gap
- the neurotransmitters then set off a new electrical signal in the next neurone.
- the transmission of the nervous impulse is very fast but it slows down as the diffusion of the neurotransmitters across the gap takes time

Question 75

Neurotransmitters

Answer 75

Chemicals that transfer nerve signals across the gap. They set off a new electrical signal in the next neurone.

Question 76

How fast is the transmission of the nervous impulse

Answer 76

It is very fast however slows down at the synapse as the diffusion of the neurotransmitters across the gap takes time

Question 77

Reflexes

Answer 77

Automatic, rapid responses to a stimulus which reduces the chance of being injured

Question 78

Reflex arc

Answer 78

A passage of information in a reflex from the receptor to the effector.

Question 79

What do the neurones in the reflex arcs do

Answer 79

• The neurones in the reflex arcs go through the spinal cord or through an unconscious part of the brain.
  1. When a stimulus is detected by the receptors, impulses are sent along a sensory neurone to a relay neurone to the CNS.
  2. When the impulses reach a synapse between the sensory neurone and the relay neurone, they trigger neurotransmitters to be released. These causes impulses to diffuse across the synapse and to be sent along the relay neurone
  3. When the impulses reach a synapse between the relay and motor neurone, the neurotransmitters are triggered to be released, causing the impulses the travel along the motor neurone.
  4. The impulses then travel along the motor neurone to the effector- muscle or gland
  5. The muscle contracts or the gland secretes hormones
  6. As you don’t have time to think about the response, it is quicker than the normal response

Question 80

How do reflexes protect the eye

Answer 80

1. Light receptors in the eye detect bright light and sends messages along the sensory neurone to the brain.
2. The message then travels along the relay neurone to the motor neurone which tells the circular muscles in the iris to contract, making the pupil smaller.

Question 81

Uses of mitosis in organisms

Answer 81

• reproduce
• grow and replace cells
• asexual reproduction
• development of embryos

Question 82

Advantages and disadvantages of stem cells in medicine

Answer 82

ADVANTAGES:
- treats a wide variety of diseases
- organs developed from a patients own stem cells reduce the risk of organ rejection and waiting for an organ donation
- adult stem cells are used successfully in a variety of treatments

DISADVANTAGES:
- rejection
- stem cells can become infected with a virus and could be transmitted to the patient
- risk of stem cells getting mutations leading them to develop cancer cells
- low numbers of stem cells donor

Question 83

Why are reflexes quicker than normal response

Answer 83

You don’t have to spend time to think about the response making it quicker than the normal response

Question 84

How many types of tumours exist

Answer 84

2:
1. Malignant tumours
2. Benign tumours

Question 85

Malignant tumours

Answer 85

Can invade neighbouring tissues and spread throughout the body in the blood leading to the creation of more secondary tumours

Question 86

Benign tumours

Answer 86

Stay in a specific part of the body often within a membrane

Question 87

Why is it important that the daughter cells have the same chromosomes as each other

Answer 87

So it can be used for growth and repair of tissues.
Asexual reproduction

Question 88

What is growth

Answer 88

An increase in size of number of cells by mitosis

Question 89

Which zone is nearest to the tip of the root

Answer 89

Zone of cell division

Question 90

Which zone is where the new cells grow in size

Answer 90

Zone of elongation

Question 91

Which zone is where the new cells differentiate and become specialised into different types of cells

Answer 91

Zone of differentiation

Question 92

What is cancer

Answer 92

A group of diseases where changes in cells lead to uncontrolled growth and division of cells

Question 93

Where does cell differentiation primarily happen

Answer 93

• human embryos
• in plants throughout their lives

Question 94

Where are stem cells found in

Answer 94

• bone marrow
• plant meristems
• human embryos

Question 95

What are stem cells

Answer 95

Stem cells are undifferentiated cells that haven’t yet specialised to do a specific function. They can create more stem cells or differentiate (become a different type of body cell) to perform another function.

Question 96

How could stem cells be used to help diabetes or paralysis

Answer 96

Stem cells can be used to replace damaged cells that cause diabetes or paralysis

Question 97

Uses for stem cells

Answer 97

1. Stem cell treatments
2. Therapeutic cloning

Question 98

Describe the stage of the cell cycle that takes place before mitosis

Answer 98

Interphase occurs before mitosis. This is where extra sub cellular structures are produced.
Chromosomes are replicated so there are 2 sets in the cell

Question 99

Describe what happens during mitosis

Answer 99

1. 2 sets of chromosomes are separated by being pulled to opposite ends of the cell.
   2, the nucleus divides into 2.
2. The cytoplasm and the cell membranes divide this is called cytokinesis
3. This then makes 2 genetically identical daughter cells

Question 100

Which processes involve the production of identical daughter cells

Answer 100

1. Asexual reproduction
2. Repair
3. Growth

Question 101

How can yeast produce alcohol and carbon dioxide

Answer 101

Yeast can respire anaerobically which is known as fermentation

Question 102

What does the myelin sheath do

Answer 102

It acts as an electrical insulator speeding up the electrical impulse

Question 103

What do effectors do

Answer 103

Bring about actions in response to a change in the internal or external environment

Question 104

How does the CNS respond to a stimuli

Answer 104

Via reflex arc

Question 105

What initiates signalling processes within the body

Answer 105

Receptors

Question 106

Rejection

Answer 106

If the transplanted cells aren’t grown using the patients own stem cells, the patients body may recognise the cell as foreign and trigger the immune response to try to get rid of them. The patient can take drugs to suppress this response, but this makes them susceptible to disease

Question 107

Potential risks of stem cells used in;medicine

Answer 107

Tumour development
Disease transmission
Rejectiin