Organisation

Question 1

Where are carbohydrates found and what do they do

Answer 1

Found in starchy foods. Provides energy for chemical reactions

Question 2

3 uses of lipids (fats and oils)

Answer 2

Provides energy
Insulation
Protects organs

Question 3

What are vitamins A,C,D needed for?

Answer 3

Vitamin A- Good vision and healthy skin
Vitamin c - prevent scurvy
Vitamin d - absorb calcium

Question 4

Why does increase of temperature only accelerate the rate of enzyme action until 37 degrees

Answer 4

High temperature starts to break apart bonds holding the enzyme together.
The active site begins to change shape.
If it changes shape too much the active site of the enzyme won’t be able to bind to the substrate.
Enzyme denatured

Question 5

Why does increase of pH only increase rate of enzyme action until 7 pH

Answer 5

High pH causes some of the bonds holding the enzyme together to start to break
Active site begins to shape (enzyme action will still work but at a slower rate)
Then eventually the active site changes so much that the substrate can’t fit.
Enzyme has been denatured

Question 6

What does fibre do

Answer 6

Help food move through our intestines properly.

Question 7

What is the Locke and Key model

Answer 7

Scientists thought that the substrate has to fit perfectly into the active site like a key fits perfectly into a dood

Question 8

What is the induced fit model

Answer 8

The enzymes active site actually changes shape slightly as it binds to the substrate

Question 9

Order of the digestive system

Answer 9

Mouth > Stomach > Small intestine > Large intestines

Question 10

What happens in the mouth in the digestive system

Answer 10

Chew to digest food
Saliva is from salivary glands helps, releases salivary amylase which breaks down carbohydrates.

Question 11

What happens in the stomach in the digestive system

Answer 11

Contracts muscular walls to push and mix food
Produces pepsin which is a protease enzyme which breaks down proteins.
Produces hydrochloric acid which kills bacteria.

Question 12

What happens in the small intestine in the digestive system

Answer 12

Food is absorbed into the bloodstream
Produces enzymes to help digestion

Question 13

What happens in the large intestine in the digestive system

Answer 13

Absorbs excess watery food. Leaves poo and wee.

Question 14

What does the pancreas do in the digestive system

Answer 14

Creates most digestive enzymes and pushes them into the small intestines in the form of pancreatic juices.

Question 15

What does the gall bladder do in the digestive system

Answer 15

Releases bile into the small intestine

Question 16

What are the 2 main roles of bile in the small intestine

Answer 16

Neutralises acid from the stomach, does this to make pH levels more ideal for the digestive enzyme to function.
Emulsifying fats (breaks down fats into droplets). It does this so there’s a bigger surface area for digestive enzymes to work on

Question 17

How is the villi in the small intestine adapted for its function

Answer 17

Increases surface area. Digested food can be absorbed into the bloodstream quicker.
Single layer of surface cells. Nutrients can diffuse over a shorter distance
Very good blood supply. To keep a concentration gradient

Question 18

What is haemoglobin

Answer 18

The protein in red blood cells which allows them to transport oxygen around

Question 19

What does protease do and where is it made?

Answer 19

Breaks down proteins into amino acids
Made in:
stomach
Pancreas
Small intestine

Question 20

Where is Amylase made and what does it do?

Answer 20

Made in:
Salivary glands
Pancreas
Small instestine

Breaks down starch into smaller sugars (maltose molecules)

Question 21

What does maltose do

Answer 21

Breaks down maltose molecules into glucose

Question 22

What does lipase do and where is it made

Answer 22

Breaks down lipids (fat and oils) into fatty acids and glycerol.
Made in:
Pancreas
Small intestine

Question 23

What is the test for sugars (with explanation)

Answer 23

Benedict’s test
Put 10 drops of Benedict’s solution into 5cm^3 of the sample
Put it in a 75 C water bath
If sugar is present it green, yellow or brick red.

Question 24

What is the test for starch

Answer 24

Iodine test
Add iodine solution to 5cm^3 of the sample
It will immediately turn to a browny orange colour
When shaken it will turn to a blue/black colour of starch is present

Question 25

What is the test for protein

Answer 25

Biuret test
Add 2cm ^3 of the biuret solution to a test tube with 2cm^3 of the solution
It will turn blue immediately
When shaken the solution will turn punk or purple if protein is present

Question 26

What is the test for lipids

Answer 26

Sudan III test
Add 3 drops of Sudan solution to the sample
Bright red layer will appear on the top of the test tube when shaken if lipids are present

Question 27

How are the alveoli adapted for gas exchange

Answer 27

Single cell thin walls - shorter distance for diffusion which increase the rate of diffusion
Very large surface area
Alveoli walls are moist which allow gases to dissolve - also increases the rate of diffusion

Question 28

Explain how gas exchange works in the alveoli

Answer 28

Oxygen diffuses out of the alveoli into the blood in the capillaries
Carbon dioxide diffuses out of the blood in the capillaries into the alveoli which we then breathe out.

Question 29

How to work out breathing rate

Answer 29

Number of breaths taken / number of minutes

Question 30

Function of arteries

Answer 30

Carry blood away from the heart to the body

Question 31

3 adaptations of artery

Answer 31

Muscle tissue provides strength and allows the arteries to direct blood flow
Elastic tissue allows the tissue to stretch and recoil
Narrow lumen which keeps the blood pressure high

Question 32

Function of capillaries

Answer 32

Exchange nutrients and waste products with the tissues

Question 33

2 adaptations of capillaries

Answer 33

Single cell thick walls which means shorter distance for diffusion
Permeable walls which means substances are able to move through them

Question 34

Function of vein

Answer 34

Carry blood from the body back to the heart

Question 35

Describe the structure of vein

Answer 35

Thin walls and wide lumen
Valves

Question 36

In what order does blood flow through the three types of blood vessels

Answer 36

Heart arteries capillaries veins heart

Question 37

Adaptations of red blood cells

Answer 37

No nucleus. More space for oxygen and haemoglobin
Shaped like a biconcave disk, more surface area for absorbing oxygen