B3 Nutrition, Digestion and Respiration

Question 1

Name the 7 components of a healthy diet:

Answer 1

Carbohydrate
Protein
Fat (lipids)
Fibre
Vitamins
Minerals
Water

Question 2

State the difference between simple and complex carbohydrates.

Answer 2

Simple carbohydrates are individual glucose (sugar) molecules.
Complex carbohydrates (starch) are made of a long chain of glucose molecules bonded together.

Question 3

Why do we need carbohydrates in our diet?

Answer 3

Carbohydrates provide a source of energy.

Question 4

Why do we need protein in our diet?

Answer 4

Protein is needed for growth and repair of body tissue.

Question 5

Why do we need fat (lipids) in our diet?

Answer 5

Fats (lipids) are used for insulation and as a store of energy.

Question 6

Why do we need fibre in our diet?

Answer 6

Fibre (roughage) is needed for good gut health as it keeps food moving through our digestive system.

Question 7

Why do we need vitamins and minerals in our diet?

Answer 7

Vitamins and minerals are needed in small amounts to keep us healthy.

Question 8

Why do we need water in our diet?

Answer 8

Water is the main component of blood and cytoplasm in our cells.

Question 9

Why does our body need iron?

Answer 9

Iron is a mineral that is important for red blood cells.

Question 10

Why does our body need calcium?

Answer 10

Calcium is a mineral that is needed for strong bones and teeth.

Question 11

What are ‘calories’ a measure of?

Answer 11

Energy in food.

Question 12

What do the units kJ and kcal mean?

Answer 12

kJ means kilo Joules, or thousand Joules
kcal means kilo calories, or thousand calories

Question 13

What is the recommended daily ‘calorie’ (kcal) intake for an average adult male and female.

Answer 13

2500 kcal for a male
2000 kcal for a female

Question 14

State any factors that affect daily calorie need.

Answer 14

Age
Weight (build)
Biological sex
Activity levels (occupation)
Health
Other - Metabolism, outside temperature, weight loss regime etc.

Question 15

What is a nutritional deficiency?

Answer 15

When there is not enough of a particular nutrient in the diet to maintain good health.

Question 16

What deficiency is caused by a lack of vitamin C, what are the symptoms, and how can it be avoided?

Answer 16

Scurvy
Red lips, gums and tongue.
Eat more fresh fruit (and veg).

Question 17

What deficiency is caused by a lack of vitamin D (and calcium) and what are the symptoms, and how can it be avoided?

Answer 17

Rickets
Soft or deformed bones
Eat more oily fish and dairy products (More sunlight - not diet)

Question 18

What deficiency is caused by a lack of iron and what are the symptoms, and how can it be avoided?

Answer 18

Anaemia
Tiredness, pale/yellow skin and nails
Eat more red meat, pulses and leafy greens

Question 19

State 4 health conditions that obese people are at an increased risk of developing.

Answer 19

(Type 2) Diabetes
Heart disease
Some types of cancer
Stroke

Question 20

What factors can lead to increased risk of heart disease?

Answer 20

Too much fat in diet
Too much sugar in diet
Other lifestyle factors e.g. drugs

Question 21

What must be done to a food sample prior to testing it for nutrients and why?

Answer 21

It should be crushed up with water and strained to remove solids.

Question 22

State the test for starch and what you would expect from a positive result.

Answer 22

Test sample with drops of iodine.
Orange/brown iodine should turn blue/black if starch present.

Question 23

State the test for lipids (fats) and what you would expect from a positive result.

Answer 23

Add sample to ethanol (and water), then shake well.
Clear ethanol should turn cloudy if fats present.

Question 24

State the test for glucose (sugar) and what you would expect from a positive result.

Answer 24

Add blue benedicts solution to sample and place in hot water bath (approx 85°C) for 3-5 minutes.
Colour change to green/yellow shows small quantity of glucose.
Colour change to orange/brick red shows large quantity of glucose.

Question 25

State the test for protein and what you would expect from a positive result.

Answer 25

Add blue biuret solution to sample and shake.
Colour change to purple/pink if protein present.

Question 26

What is the function of digestion?

Answer 26

To break down food so that nutrients can be absorbed.

Question 27

State the difference between mechanical and chemical digestion and give an example of each.

Answer 27

Mechanical - through forces e.g. Chewing, stomach contractions
Chemical - through chemical reactions e.g. Acid in stomach, enzymes

Question 28

What factors affect rate of diffusion?

Answer 28

Temperature
Concentration gradient
Length of diffusion pathway

Question 29

State the adaptations of the small intestine and how they aide nutrient absorption.

Answer 29

Long - higher surface area and more time for absorption
Villi (and microvilli) - higher surface area
Rich blood supply - maintains a high concentration gradient
Thin walls (one cell thick) - short diffusion pathway

Question 30

What is the functions of enzymes in digestion.

Answer 30

To break down large food molecules into smaller molecules so that they can be absorbed into the blood.

Question 31

Name the enzyme used to break down starch (carbohydrates) and the small molecules it is broken down into.

Answer 31

Carbohydrase (Amylase)
Starch is broken down into glucose.

Question 32

Name the enzyme used to break down protein and the small molecules it is broken down into.

Answer 32

Protease
Protein is broken down into amino acids.

Question 33

Name the enzyme used to break down fats (lipids) and the small molecules it is broken down into.

Answer 33

Lipase
Fats are broken down into fatty acids and glycerol.

Question 34

Why is it beneficial to have certain bacteria living within the human digestive system?

Answer 34

Bacteria…
Break down some nutrients that enzymes can’t break down
Produce essential vitamins (B and K)
Reduce chances of harmful bacteria

Question 35

What is respiration?

Answer 35

A chemical reaction that releases energy from glucose.

Question 36

Write the word equation for aerobic respiration.

Answer 36

Glucose + Oxygen → Carbon Dioxide + Water

Question 37

Within which organelle (part of cell) does respiration occur?

Answer 37

Mitochondria

Question 38

Write the word equation for anaerobic respiration in animals.

Answer 38

Glucose → Lactic acid

Question 39

Write the word equation for anaerobic respiration in plants and yeast.

Answer 39

Glucose → Carbon dioxide + Ethanol

Question 40

State the alternative name given to anaerobic respiration in yeast.

Answer 40

Fermentation

Question 41

Compare aerobic and anaerobic respiration

Answer 41

Aerobic
Reactants are glucose and oxygen
Products are carbon diaxide and water
Occurs slowly
Releases lots of energy

Anaerobic
Reactant is Glucose
Product is lactic acid
Occurs quickly
Releases less energy