Digestion

Question 1

What are carbohydrates used for?

Answer 1

Store of Energy
Fuel for Respiration (glucose is a carb)

Question 2

What are Proteins used for?

Answer 2

Growth and repair of cells/tissues
Fuel for respiration

Question 3

What are Lipids used for

Answer 3

Thermal insulation
Store of energy
Fuel for respiration

Question 4

What is water used for?

Answer 4

Regulating temperature
Used to transport substances in blood plasma

Question 5

What is fibre used for?

Answer 5

It is mainly cellulose
Helps movement of food through small intestine
Prevents constipation and bowel cancer

Question 6

Protein –>

Answer 6

(Peptides) –> Amino acids

Question 7

Carbohydrates –>

Answer 7

(Maltose) –> Glucose

Question 8

Lipids –>

Answer 8

Glycerol + Fatty acids

Question 9

Which enzyme breaks down protein into peptides and where is it made?

Answer 9

Protease - Pepsin made in Stomach

Question 10

Which enzyme breaks down peptides into amino acids and where is it made?

Answer 10

Protease - Trypsin made in Pancreas

Question 11

Which enzyme breaks down carbohydrates into maltose and where is it made?

Answer 11

Carbohydrase- Amylase made in pancreas and salivary glands

Question 12

Which enzyme breaks down maltose into glucose and where is it made?

Answer 12

Carbohydrase - Maltase made in Pancreas

Question 13

Which enzyme breaks down Lipids into fatty acids and glycerol and where is it made?

Answer 13

Lipase made in Pancreas, secreted into the small intestine.
Bile (not an enzyme) emulsifies lipids made in liver.

Question 14

What are the functions of bile?

Answer 14

To neutralise stomach acid.
To emulsify lipids.

Question 15

How is the small intestine adapted for diffusion?

Answer 15

Large Surface Area - Folds in walls, many villi and microvilli.
Short diffusion distance - Villi walls are once cell thick, each villus has its own set of capillaries.
High concentration gradient - Capillary network and lacteals removing absorbed molecules.

Question 16

Why doesn’t amylase work in the stomach?

Answer 16

The enzyme is denatured as the stomach acid is too acidic, not the right pH.

Question 17

Why might someone with Anaemia feel tired?

Answer 17

Lack of iron, less haemoglobin made, less oxygen carried, less aerobic respiration, less energy

Question 18

What is the purpose of digestion?

Answer 18

To break down large ,insoluble molecules into into smaller ,soluble molecules that can be absorbed into the blood stream.

Question 19

What can we do to improve limitations of the Energy Content in a food sample practical?

Answer 19

Incomplete burning of the food sample - Relight it until it no longer lights up
Heat energy is lost to the surroundings - Whilst heat lost means that the energy calculation is not very accurate, so long as the procedure is carried out in exactly the same way each time (with the same distance between food sample and boiling tube), we can still compare the results

Question 20

Describe the Energy content in a food sample practical.

Answer 20

Use the measuring cylinder to measure out 25cm3 of water and pour it into the boiling tube
Record the starting temperature of the water using the thermometer
Weigh the initial mass of the food sample
Set fire to the sample of food using the bunsen burner and hold the sample 2cm from the boiling tube until it has completely burned
Record the final temperature of the water
(Once cooled) weigh the mass of any remaining food and record
Repeat the process with different food samples
e.g. popcorn, nuts, crisps

Question 21

How is the small intestine adapted for absorption?

Answer 21

Large Surface Area - Many microvilli
Short diffusion distance - Villi’s walls are one cell thick.
Steep Concentration Gradient - The villi are well supplied with a network of blood capillaries that transport glucose and amino acids away from the small intestine in the blood
A lacteal runs through the centre of the villus to transport fatty acids and glycerol away from the small intestine.

Question 22

In which part of the small intestine are digested food molecules absorbed?

Answer 22

Ileum

Question 23

In which part of the small intestine does chemical digestion occur?

Answer 23

Duodenum

Question 24

Which enzymes are made in the pancreas?

Answer 24

Trypsin, lipase, maltase and amylase

Question 25

What is iron used for?

Answer 25

Forms part of haemoglobin which binds to oxygen

Question 26

What is the deficiency disease for iron?

Answer 26

Anaemia

Question 27

What is calcium used for?

Answer 27

Needed to form bones and teeth

Question 28

What is the deficiency disease for calcium?

Answer 28

Rickets (weak bones)

Question 29

What is vitamin A used for?

Answer 29

Making a chemical in the retina and also protects the surface of the eye

Question 30

What is the deficiency disease for vitamin A?

Answer 30

Night blindness and damaged cornea

Question 31

What is vitamin C used for?

Answer 31

Needed for cells and tissue to stick together

Question 32

What is the deficiency disease for vitamin C?

Answer 32

Scurvy

Question 33

What is vitamin D used for?

Answer 33

Needed to absorb calcium and phosphate ions from food

Question 34

What is the deficiency disease for vitamin D?

Answer 34

Rickets, caused by weak bones (lack of calcium)