Keeping Healthy (nutrition)

Question 1

What is a nutrient?

Answer 1

Nutrients are molecules which the body needs for many functions.

Question 2

What is a balanced diet?

Answer 2

If we eat a balanced diet, we are eating different foods and nutrients in the correct amounts.

Question 3

What are the impacts of an unbalanced diet?

Answer 3

• suffer from malnutrition
• lack of fibre -> constipation
• lack of protein -> poor growth and repair
• too much carbohydrate -> overweight/bad teeth

Question 4

What is protein?

Answer 4

• The main structures of our bodies are made of protein
• we need protein for growth and repair
• many immune and digestive functions rely on proteins
• a test with Biret solution turns purple
• e.g. meat, milk, cheese, eggs, nuts

Question 5

What are carbohydrates?

Answer 5

• carbohydrates give us energy
• starches turn blue or black in a test with Iodine solution
• e.g. bread, rice, pasta
• sugars give a red precipitate in a test with Benedict’s solution
• e.g. sweets, cakes

Question 9

What are fats?

Answer 9

• contain about twice the energy of carbohydrates and protein
• also used in cell membranes
• test with Ethanol, gives a white emulsion
• e.g. butter, oils, cheese

Question 10

What is fibre?

Answer 10

• used in cellulose (cell wall of plants)
• we cannot digest it
• keeps our intestines clean and healthy
• unblocks the intestine
• e.g. whole meal foods, fruit and veg

Question 11

What causes obesity?

Answer 11

Too many calories

Question 12

What causes heart disease?

Answer 12

Too much saturated fat

Question 13

What causes high blood pressure?

Answer 13

Too much saturated fat/salt

Question 14

What causes diabetes?

Answer 14

Too many sugary foods

Question 15

What causes deficiency diseases?

Answer 15

Lack of a particular nutrient

Question 16

What causes rickets?

Answer 16

Lack of vitamin D

Question 17

What causes scurvy?

Answer 17

Lack of vitamin C

Question 18

What causes anaemia?

Answer 18

Lack of iron

Question 19

What is digestion?

Answer 19

The process by which food is broken down into smaller molecules so that it can be absorbed by the body.

Question 20

What parts of the body are used in digestion?

Answer 20

• Gullet/oesophagus
• stomach
• small intestine
• large intestine (colon)
• rectum

Question 21

What is the gullet/oesophagus?

Answer 21

• when you swallow, the trachea is closed
• the muscles in the wall of the gullet contract when they are above the food
• this pushes food to the stomach, through a process called peristalsis

Question 22

What is the stomach?

Answer 22

In the stomach, food is churned up by highly concentrated Hydrochloric acid of pH 1-2
The muscles inside the stomach are able to withstand this constant exposure to acid.

Question 23

What is the small intestine?

Answer 23

• nutrients in food are made up of molecules
• large molecules are broken down by digestive enzymes and absorbed through the wall of the small intestine
• contains ~1kg of bacteria
• lines with Villi

Question 24

What are villi?

Answer 24

• a villius is a hair-like structure
• thin
• good blood supply
• give the small intestine a large surface area, which helps with absorption

Question 26

What is the large intestine?

Answer 26

• Food that cannot be digested in the small intestine is squeezed through here
• the water is removed
• Any solid material that is left becomes faeces
• about 60% of faeces is dead bacteria
• contains the appendix, which is an evolutionary artefact. When pathogenic bacteria in the intestines are killed, some beneficial bacteria may hide here (just a theory)

Question 27

What is the rectum?

Answer 27

• faeces are stored here
• deposited by anus
• process called egestion
• ingestion -> egestion transit time is approximately 24-28 hours
• the guy is 8 metres long

Question 28

What is absorption?

Answer 28

• only small, water soluble molecules can be absorbed through the small intestine
• these are vitamins, minerals and sugars (glucose, sucrose, etc.)
• fats, proteins and starches need to be broken down properly
• this is done by digestive enzymes

Question 29

What are digestive enzymes?

Answer 29

A digestive enzyme is a chemical (protein) that breaks down large protein, carbohydrates and fat molecules into smaller molecules that can be absorbed by the body via the small intestine.

Question 30

What are the three main digestive enzymes and what do they do?

Answer 30

• amylase breaks down starches into glucose
• lipase breaks down fats into fatty acids and/or glycerol
• protease breaks down proteins into amino acids