Human Nutrition

Gives you all the essential nutrients you need in the right proportions
Includes carbohydrates, proteins, lipids, vitamins, minerals and water
Need fibre

Provides energy
Bread, pasta, rice, potatoes
If you are deficient, you will be weak, tired and lack energy

Needed for growth and repair of tissue
Provides energy in emergencies
Meat, fish
If you are deficient, you will have stunted growth, a lack of energy and fatigue

Provides energy
Acts as an energy store
Provides insulation
Butter, oily fish

Helps to improve vision
Keeps skin and hair healthy
Carrots, liver

Prevents scurvy
Repairs damaged tissue
Oranges, lemons, oily fish
If you are deficient, you will be weak and tired

Needed for calcium absorption
Eggs
If you are deficient, you will have brittle bones and weak teeth

Strengthens bones and teeth
Milk, cheese
If you are deficient, you will have brittle bones and weak teeth

Needed to make haemoglobin in red blood cells
Red meat, spinach

Aids the movement of food through the gut
Wholemeal bread, fruit, dates
If you are deficient, you will have constipation

Needed for almost every bodily function
Found in almost all food and drink
If you are deficient, you will have dehydration

Active people need more energy than people who aren't very active

Children and teenagers need more energy than older people because they need energy to grow and they are generally more active

Pregnant women need more energy than other women as they have got to provide the energy their babies need to develop

The teeth break down larger pieces of food into smaller ones (mastication)
Salivary glands release saliva containing salivary amylase which starts the breakdown of starch into glucose
Tongue rolls food into a ball which makes it easier to swallow

Produces bile

Muscles in the stomach wall churn food
Gastric glands release pepsin which breaks down proteins into amino acids
Stomach wall secretes hydrochloric acid which kills bacteria and gives the optimum pH for pepsin (pH 2) to work
Semi-digested food held in stomach by a ring of muscle (sphincter muscle) which, when it relaxes, releases the food into the small intestine

Produces digestive enzymes (carbohydrases, proteases and lipases) and sends them via the pancreatic duct into the small intestine

Breaks starch down into maltose
Produced by salivary glands in the mouth

Breaks down strach into maltose
Produced by pancreas

Breaks down maltose into glucose

Break down proteins into amino acids

Breaks down lipids into fatty acids and glycerol

Made up of duodenum and ileum

Digestive enzymes break down some carbohydrates, all the lipids and some proteins
Bile neutralises acidic food so that the enzyme active site doesn't denature

Covered in villi to increase the surface area and each villi has microvilli
Has good blood supply to maintain concentration gradient
Has thin walls
Amino acids and glucose are absorbed into blood supply

Muscular tube that connects mouth and stomach
Uses peristalsis to push food down it

A wave of muscle contractions

Stores bile

Absorbs water from the food

Stores faeces before it is released through the anus

Produced in the liver
Stored in the gall bladder before it's released into the small intestine
Hydrochloric acid in the stomach makes the pH to acidic for enzymes so bile, which is an alkaline, neutralises the acid and makes the conditions alkaline as enzymes in the small intestine work best in alkaline conditions
Bile emulsifies lipids to increase the surface area of the lipid so that lipase can break it down quicker and more easily

Energy in food (J) = mass of water (g) x temperature change x 4.2

Weigh food
Place food on mounted needle
Place 25cm3 of water into a boiling tube
Record temperature of water
Light food in a Bunsen burner flame
Hold burning food under the boiling tube until it has finished burning
Record temperature

Some energy is lost to the surroundings
Small piece of food is not representative of nutrients
There could still be energy left as it might not have fully burnt

Insulate boiling tube to minimise heat loss and keep more energy in the water, making results more accurate