Human Diet and Nutrition

Question 1

Label this diagram of the alimentary canal

Answer 1

Question 2

What are the seven main components of diet?

Answer 2

Carbohydrates

Proteins

Lipids (fats)

Vitamins

Minerals

Water

Dietary fibres

Question 3

What is the food source and function of carbohydrates?

Answer 3

Carbohydrates are found in pasta, rice and sugar

Its function is to provide energy (fuel for respiration)

Question 4

What is the food source and function of proteins?

Answer 4

Food source of proteins are meat and fish

Proteins are needed for growth and repair of tissues, and to provide emergency energy (fuel for respiration)

Question 5

What is the food source and function of lipids (fats)?

Answer 5

The food source of lipids are butter and oily fish

The function is to provide energy (for respiration), to act as an energy store, and to provide insulation

Question 6

What activities are likely to use more energy or calories?

Answer 6

We use around 70% of energy each day just keep a body running: heartbeat, transporting nutrients and cell repair.

More calories are used by:

people in active jobs such as a builder

teenagers growing

pregnant women

Question 7

What unit is energy measured in?

Answer 7

Kilojoules (kJ)

Question 8

How do you measure the amount of energy in food?

Answer 8

By burning the food, and seeing how much heat energy is given off

Question 9

What are minerals?

Answer 9

Minerals are chemical elements which are needed in the diet to help the body to function in a variety of ways

Question 10

For the mineral iron what is its function, food sources and deficiency disease?

Answer 10

Iron is needed to make haemoglobin which binds to oxygen for healthy blood

Food sources of iron are red meat, liver and spinach.

The deficiency disease of iron is anaemia

Question 11

For the mineral calcium what is its function, food sources and deficiency disease?

Answer 11

Calcium is needed to form bones and teeth

The food sources of calcium are fish, dairy products and fresh vegetables

The deficiency disease for lack of calcium is Ricketts

Question 12

What are the symptoms of anaemia, and what is it caused by?

Answer 12

Anaemia often causes the interior of the lower eyelid to appear pale pink. Other symptoms are chronic fatigue.

Question 13

What are the symptoms of ricketts, and what causes it?

Answer 13

Ricketts can also be called ‘bendy bones’. A symptom is malformed legs.

Ricketts are caused by a lack of calcium.

Question 14

What are vitamins?

Answer 14

Vitamins are chemicals which help the body to function properly. Each vitamin is asigned a letter

Question 15

For vitamin A, what is its use in the body, its food source and the effect of deficiency?

Answer 15

Vitamin A helps to protect the surface of your eye, improves vision, and keeps your skin and hair healthy

The food sources of vitamin A are liver, butter and carrots.

Effect of a deficiency of vitamin A is night blindness and a damaged cornea.

Question 16

For vitamin C, what is its use in the body, food sources and the effect of deficiency?

Answer 16

Vitamin C is used to help cells and tissues stick together.

Food sources of vitamin C include fresh fruit and vegetables.

Effects of a deficiency of vitamin C is scurvy.

Question 17

For vitamin D, what is it to use in the body, food sources and the effect of deficiency?

Answer 17

Vitamin D is needed for calcium absorption.

Food sources of vitamin D are dairy products and eggs. We can also get vitamin D from the sun.

The effect of a deficiency is ricketts, causing weak bones.

Question 18

Why is water essential in the dietary system?

Answer 18

Water is an essential solvent, it allows things to be dissolved into it. It is used to transport the components of blood and is crucial for temperature regulation, e.g. sweating.

Question 19

What is the chemical name for fibre in a balanced diet, what is it used for, and what is a good source of it?

Answer 19

Dietary fibre

It helps the movement of food through the gut.

Fruit, vegetables and wholemeal bread are good sources of dietary fibres.

Question 20

What are the five processes that take place in the alimentary canal?

Answer 20

Food is ingested, digested, absorbed and egested from the alimentary canal.

During this time the food is also assimilated.

Question 21

What is ingestion, a stage as food moves through the alimentary canal?

Answer 21

ingestion means taking food in through the mouth and swallowing

Question 22

What is digestion, a stage as food moves through the alimentary canal?

Answer 22

Digestion means breaking down food into smaller pieces - physical digestions, and smaller molecules - chemical digestion.

Question 23

What is absorption, a stage as food moves through the alimentary canal?

Answer 23

Absorption means taking small food molecules out of the gut and into the blood.

Question 24

What is assimilation, a stage as food moves through the alimentary canal?

Answer 24

Assimilation means using molecules gained from food to build new molecules, cells and tissues for the body.

Question 25

What is egestion, a stage as food moves through the alimentary canal?

Answer 25

Egestion means passing out undigested food through the anus.

Question 26

What are the two types of digestion that takes place in the mouth?

Answer 26

Mechanical and chemical digestion take place in the mouth.

Question 27

How does mechanical digestions help the digestive system?

Answer 27

Mechanical digestion is the breaking up of food into smaller pieces in the mouth. This process helps because it increases the surface area for enzymes and also prevents discomfort when swallowing.

Question 28

How does chemical digestions work in including the enzyme amylase?

Answer 28

Saliva is released in to the mouth by the salivare gland. It lubricates the food but also contains the enzyme amylase. Amylase breaks down the carbohydrates.

Question 29

What does the epiglottis do?

Answer 29

Before swallowing the food is shaped into a ball or bolus. The epiglottis is a flap which blocks the food from entering the windpipe (trachea). It means food enters the alimentary canal as it should.

Question 30

What is the oesophagus?

Answer 30

The oesophagus is a long pipe that connects the mouth to the stomach. Food gets pushed down the oesophagus by the muscles during peristalsis.

Question 31

What is peristalsis?

Answer 31

Peristalsis is how food is pushed down the oesophagus or through the small and large intestines. It is where circular muscles contract and relax as longitudinal muscles relax and contract. The two sets of muscles work together to push the food along.

Question 32

What two types of digestion take place in the stomach?

Answer 32

As in the mouth, two types of digestion: mechanical and chemical. Mechanical is where the muscles in the stomach wall churn the contents ensuring all contents are covered in enzymes. Chemical digestions is where pepsin is released from gastric glands in the stomach wall, which breaks down protein into polypeptide in the stomach.

Question 33

In the Duodenum, part of the small intestine, what enzymes are released from the pancreas?

Answer 33

Amylase, maltese, lipase and trypsin

Question 34

What do these enzymes, released into the duodenumby the pancreas, do? Amylase Maltase Lipase Trypsin

Answer 34

Starch —amylase—\> Maltose Maltose —maltese—\> Glucose Lipids —lipase—\> 3 fatty acids and glycerol Polypeptides —trypsin—\> Amino acids

Question 35

The optimum pH for enzymes is neutral. Therefore what is released into the stomach to neutralise the stomach acids?

Answer 35

Bile

Question 36

What is Bile, where is it produced and how does it help?

Answer 36

Bile is produced by the liver and stored in the gall bladder. It is then released into the stomach by the bile duct. The enzymes in the stomach work best with a neutral pH. The bile neutralises the stomach acid. Bile salts present in the bile break up fat droplets into tiny droplets increasing the surface area. This increases the rate of emulsification.

Question 37

What is the ileum and what happens in it?

Answer 37

When food enters the ileum digestion is over and absorption begins. The ileum has many folds and is covered in finger-like projections called villi.

Question 38

How does absorption work in the ileum?

Answer 38

The large surface area, thin walls, high density of capillaries and large bloodflow all increase the rate of diffusion. Villi have small microvilli increasing surface area even more. Some food is absorbed by diffusion, some, such as glucose, are absorbed via active transport against a concentration gradient.

Question 39

What are two sections of the large intestine and what happens there?

Answer 39

The large intestine is broken into two sections, the colon and the rectum. The colon is the sites for all reabsorption of water. The faeces is then stored in the rectum and egested from the anus.

Question 40

What is egestion?

Answer 40

Egestion is the expulsion of faeces through the anus. In other words it is the removal of undigested food from the body.

Question 41

What is excretion?

Answer 41

Excretion is the removal of waste substances produced by the body, e.g. carbon dioxide is removed by the lungs and urea is removed by the kidneys and sweat.

Question 42

What is assimilation in the digestive system?

Answer 42

Assimulation takes place in all cells using the food molecules absorbed. It is where the body builds more complex molecules such as proteins.

Question 43

Carbohydrases are digestive enzymes. What do they act on and what are the end products?

Answer 43

Carbohydrases act on Carbohydrates. The end products are smaller carbohydrate molecules, e.g. glucose.

Question 44

Proteases are digestive enzymes. What do they act upon and what is the end product?

Answer 44

Proteases act upon proteins. The end products are amino acids.

Question 45

Lipases are digestive enzymes. What do they act upon and what are the end products?

Answer 45

Lipases act upon lipids (fats). The end products are glycerol and 3 fatty acids.