GCSE Revision 2/7

Question 1

What do digestive glands do

Answer 1

Produce digestive juices containing enzymes

Question 2

What does the stomach do

Answer 2

Digests food

Question 3

What does the liver do

Answer 3

Produces bile

Question 4

What does the small intestine do

Answer 4

Digests food and absorbs soluble food

Question 5

What does the large intestine do

Answer 5

Absorbs water from undigested food

Question 6

How are villi adapted (3)

Answer 6

Large surface area to absorb food molecules (by both diffusion and active transport)
Thin wall for short diffusion path
Good blood supply to carry the food molecules away

Question 7

Carbohydrates

Answer 7

Made of units of sugar
Glucose- 1 sugar
Sucrose- 2 sugars

Question 8

Lipids

Answer 8

Three molecules of fatty acids linked to one molecule of glycerol

Question 9

Proteins

Answer 9

Long chains of amino acids, folded to form a specific shape

Question 10

Lock and key model (3)

Answer 10

Substrate and enzyme meet
Substrate fits into the active site
Substrate splits into products which leave the active site; enzyme is reused

Question 11

Metabolism

Answer 11

The sum of all the reactions that take place in a cell/the body

Question 12

How do digestive enzymes work (3)

Answer 12

They are produced by specialised cells in glands and in the lining of the small intestine
They pass out of the glands into the digestive system
They come into contact with the food so it is digested

Question 13

What pH are the mouth and small intestine

Answer 13

Alkaline

Question 14

Amylase (2)

Answer 14

Produced by salivary glands, the pancreas and the small intestine
Catalyses the digestion of starch into sugars in the mouth and small intestine

Question 15

Protease (2)

Answer 15

Produced by the stomach, the pancreas and the small intestine
Catalyses the breakdown of proteins into amino acids in the stomach and small intestine

Question 16

Lipase (2)

Answer 16

Produced by the pancreas and the small intestine
Catalyses the breakdown of lipids to fatty acids and glycerol

Question 17

What does bile do

Answer 17

It neutralises the stomach acid
Makes conditions slightly alkaline
Emulsifies fats (breaks large drops of fat into smaller ones) to increase the SA of the fats for lipase to work on

Question 18

Where is bile produced

Answer 18

The liver

Question 19

Where is bile stored

Answer 19

The gall bladder

Question 20

What is blood and what is it made up of

Answer 20

Blood is a tissue made up of plasma. The plasma contains red blood cells, white blood cells and platelets

Question 21

What does the blood transport (3)

Answer 21

CO2 from the organs to the lungs (and oxygen the other way)
Soluble products of digestion from the small intestine to other organs
Urea from the liver to the kidneys

Question 22

Red blood cells (3)

Answer 22

Biconcave
No nucleus
Contain haemoglobin

Question 23

Haemoglobin + Oxygen

Answer 23

Oxyhaemoglobin

Question 24

White blood cells (2)

Answer 24

Have a nucleus
Form part of the body’s defense system against microorganisms

Question 25

In which ways can white blood cells protect the body

Answer 25

Some produce antibodies, some produce antitoxins, and other engulf other microorganisms

Question 26

Platelets (3)

Answer 26

Small fragments of cells Do not have a nucleus Help the blood to clot

Question 27

How does blood clotting work

Answer 27

Platelets release chemicals that form a mesh of insoluble fibres across the wound The platelets then stick together to form clumps in the mesh This barrier stops blood cells

Question 28

Arteries (3)

Answer 28

Carry blood AWAY from the heart Have thick walls containing another thick layer of muscle and elastic tissue Small lumen

Question 29

Veins (4)

Answer 29

Carry blood TOWARDS the heart Have thinner walls than arteries Large lumen Valves along their length to prevent backflow of blood

Question 30

Capillaries (4)

Answer 30

One cell thick Narrow lumen Carry blood through the organs Allow the exchange of substances with all the living cells in the body

Question 31

Heart cycle (beginning in right atrium)

Answer 31

Right atrium - right ventricle - pulmonary artery - lungs - pulmonary vein - left atrium - left ventricle - aorta - rest of the body- vena cava

Question 32

Coronary artery

Answer 32

The heart muscle is supplied with blood from these arteries, which come just before the aorta

Question 33

How does coronary heart disease occur

Answer 33

When the coronary arteries become blocked/narrow due to a buildup of fatty material inside them

Question 34

How does a stent work (3)

Answer 34

It is a metal mesh placed in the artery A tiny balloon is inflated to open up the blood vessel and the stent The balloon is removed, but the stent remains

Question 35

How do statins work

Answer 35

They reduce blood cholesterol levels which slows down the rate at which fatty material is deposited in the coronary arteries

Question 36

What problems could leaky valves cause

Answer 36

Blood could flow in the wrong direction

Question 37

How can you counter leaky valves

Answer 37

Replace them with artificial or animal valves

Question 38

How is your heart rate controlled

Answer 38

Controlled by a group of cells in the right atrium that form a natural pacemaker

Question 39

What do pacemakers do

Answer 39

Correct irregularities in the heart rhythm

Question 40

What do artificial hearts do

Answer 40

Keep patients alive while they wait for a transplant Let their heart rest as an aid for recovery

Question 41

Breathing in

Answer 41

Ribs move up and out and the diaphragm flattens; volume increases Increased volume = lower pressure Atmospheric air at higher pressure than the chest, so air is drawn into the lungs

Question 42

Breathing out

Answer 42

Ribs fall and the diaphragm moves up; volume decreases Decreased volume = increased pressure Pressure in the chest is higher than the outside, so air is forced out of the lungs

Question 43

How does the ribcage move up and down

Answer 43

The intercostal muscles between the ribs contract (moves up) and relax (moves down)

Question 44

Adaptations of the lungs

Answer 44

Large surface area Thin walls Short diffusion path Lungs are ventilated Many capillaries

Question 45

Epidermal tissue

Answer 45

Covers the plant

Question 46

Palisade mesophyll

Answer 46

Contains chloroplasts for photosynthesis

Question 47

Spongy mesophyll

Answer 47

Has many air spaces and large SA for diffusion of gases

Question 48

Xylem Phloem

Answer 48

Water and mineral ions from the root to the rest of the plant Dissolved food from the leaves to the rest of the plant

Question 49

Translocation

Answer 49

Phloem carrying dissolved sugars from the leaves to the rest of the plant

Question 50

Transpiration

Answer 50

The loss of water vapour from inside a plant from the surface of its leaves

Question 51

How does water leave the plant (3)

Answer 51

Water passes through the plant to the cells in the leaves Water then evaporates from the cells into the air spaces between them The water then diffuses out of the plant through the open stomata

Question 52

What conditions is transpiration more rapid (temp, humidity, air flow, light intensity)

Answer 52

Hot, dry, windy and bright conditions (more KE, steeper concentration gradient, steeper concentration gradient (as water vapour is blown away), more light)

Question 53

How do plants control water loss (3)

Answer 53

Waxy cuticle on top of the leaf to prevent water loss Most of the stomata are on the underside of the leaf Leaves may collapse (wilt), reducing their surface area Stomata may close (but this also stops photosynthesis)