Nutrition

Question 1

What are the adaptations of a leaf?

Answer 1

• waxy cuticle covering the upper and lower epidermis creates a water proof barrier over the surface of the leaf, reducing water loss.
• The guard cells around stomata in the lower epidermis of the leaf close in certain conditions to reduce water loss.
• air spaces between the spongy mesophyll cells of the leaf so carbon dioxide and oxygen can diffuse through the leaf.
• palisade mesophyll contains lots of chloroplasts to speed up the rate of photosynthesis

Question 2

What are magnesium ions used for in plants?

Answer 2

• required for production of chlorophyll

- leaf is yellow if mg deficiency

Question 3

What are nitrate ions used for in plants?

Answer 3

• production of proteins

- without proteins, plants cannot grow

Question 4

What is iron needed for?

Answer 4

-to make haemoglobin which carries oxygen around the body via red blood cell

Question 5

What is vitamin A needed for and where is it found?

Answer 5

• keeping the immune system healthy and for vision in dim light.
• yellow/orange fruits like oranges and carrots

Question 6

What is Vitamin D needed for and where is it found?

Answer 6

• absorbing calcium and phosphorous, which is important for keeping bones healthy
• in oily fish and egg yolks

Question 7

What is Vitamin C needed for and where is it found?

Answer 7

• making collagen, and for repairing bones and teeth.

- Vitamin C is found in citrus fruits (e.g. lemons and oranges) and blackcurrants.

Question 8

Which foods do pregnant women need more of?

Answer 8

-more daily calories, protein, calcium and iron for the growing baby.

Question 9

Which foods do breast feeding women need more of?

Answer 9

-fats, calcium and water to produce milk.

Question 10

What is the human alimentary canal and what organs are involved?

Answer 10

• where food is processed for use in the body

- mouth, oesophagus, stomach, small intestine (duodenum and ileum), large intestine (colon and rectum), pancreas

Question 11

Why does starch start to break down in the mouth?

Answer 11

-enzymes in the saliva break it down

Question 12

What is the role of the pancreas?

Answer 12

• secretes digestive enzymes into the small intestine. These enzymes are;
• Proteases
• Carbohydrases
• Lipases

Question 13

How is the small intestine adapted to it’s role?

Answer 13

-covered in structures called villi which provide a large surface area for absorbing soluble food molecules

Question 14

What is the role of the large intestine?

Answer 14

• water is absorbed through the walls of the large intestine into the blood.
• After water has been absorbed through the large intestine, undigested food leaves the body as faeces through the anus

Question 15

What is peristalsis and how does it work?

Answer 15

• food is kept moving through the oesophagus, small intestine and large intestine
• The muscular walls of the digestive system contract in waves to squeeze lumps of food along

Question 16

How are the villus adapted for their role?

Answer 16

• contains capillaries to maintain the concentration gradient for absorption of water, carbohydrates, ions and proteins, and a lacteal for fat absorption.

Question 17

What is the role of digestive enzymes?

Answer 17

-catalyse the breakdown of large, insoluble food molecules into smaller, soluble molecules that are then small enough to be absorbed into the bloodstream

Question 18

Give 4 examples of digestive enzymes.

Answer 18

• lipase
• maltase
• protease
• amylase

Question 19

What is the purpose of amylase?

Answer 19

-breaks down starch into its constituent simple sugars

Question 20

Where is amylase produced?

Answer 20

• pancreas
• small intestine
• salivary glands

Question 21

What is the purpose of maltase and where?

Answer 21

• breaks down maltose into a smaller sugar, glucose.
• This happens on the epithelial lining of the small intestine, so that glucose can pass through the membrane straight into the bloodstream

Question 22

What is the purpose of protease and where?

Answer 22

• breaks proteins into amino acids
• trypsin and pepsin are examples
• small intestine, stomach, pancreas

Question 23

What is the purpose of lipase and where?

Answer 23

• small intestine and pancreas

- breaks down lipids into glycerol and fatty acids

Question 24

What is emulsification?

Answer 24

• where bile breaks up fats into tiny droplets which have higher surface area than original droplets
• This increases the rate of the lipase-catalysed reactions that break fats down

Question 25

What is another role of bile besides emulsification?

Answer 25

-neutralises acid from the stomach to stop these enzymes becoming denatured

Question 26

What do enzymes in the small intestine operate best in?

Answer 26

-alkaline conditions