B4: Enzymes and Nutrition

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Enzymes are proteins often referred to as biological catalysts that speed up metabolic processes.

proteins are biological molecules composed of long chains of amino acids

All metabolic reactions require a certain amount of energy from the reaction to occur = activation energy

Enzymes lower the activation energy

allowing reactions to occur at body temperature - no need for extra thermal energy

Getting denatured:

- when the enxyme passes the optimum temperature it denatures ie. loses shape

as temperature goes us heat energy causes more collisions between the enzyme and the substrate

at low temperatures enzymes are inactive as they lack the kinetic energy for successful collision between the substrate and enzyme active site

as temperature increases --> particles have more kinetic energy = at optimum temperature results in more frequent and energetic collisions between substrates and enzyme

= highest rate of reaction

Enzymes denature past optimum temperature

- heat energy bonds within the enzyme are disrupted

- active site loses shape

- substrate no longer fits in = slower rate of reaction

organic substance: any substance obtained from living organisms with a carbon chain

CO and CO2 are

Carbohydrates contain: Cn, H2m, Om

double number of hydrogen than carbon

Proteins contain: C, H, O, N, (amino acids)

Lipids contain: C, H, O, N, P

1. Carbohydrates

Carbohydrates are needed to give the body energy. There are two types of carbohydrate - starch and sugar.

Starch is found in : Cereals, cornflour, potatoes, pasta and flour.

Sugar is found in: fruit, vegetables, honey, milk and malt products.

2. Fats

Fats help to provide concentrated sources of energy and help to insulate the body in cold weather. There are two main types.

Saturated fats are usually obtained from animal sources, for example butter and lard. The exceptions are coconut and palm oils.

Polyunsaturated fats come from vegetable sources, such as sunflower oil.

However, you wouldn’t want too much fat. Too much fat makes you….fat. LOL.

3. Proteins

Proteins assist with growth and repair of the body.

Proteins are found in animal products like meat, fish, cheese, milk and eggs. Vegetable sources include soya-bean products, pulses and nuts.

4. Vitamin C and D (only) —they’re making it sound like all other vitamins aren’t important XD.

Vitamin CNeeded for : healthy skin, protects cells, helps absorb ironSources: Fruit, vegetables

Vitamin DNeeded for: helps absorb calcium, strong teeth+ bonesSources: margarine, oily fish.

lipids are hydrophobic so lipase can only break down lipids on the surface of the globule

bile breaks a large fat droplet into many small droplets which cumulatively gives it a large surface area. the lipase can break it down faster as it has more access to the lipids.

bile emulsifies the fats into smaller droplets that cumulatively give them a larger surface area enabling more to be absorbed as more is exposed to the lipase. Hard before as lipids are hydrophobic = only lipids at the surface could be absorbed

proteins: made of amino acids - used in growth and repair

carbohydrates: provide energy for use

fats: insulate body and provide concentrated energy

These are finger-like projections.

Very small, approximately 1mm long.

Each villi is made up of even smaller microvilli

Villi:

Increase internal surface area of the intestinal walls.

Larger surface area for absorption

This is particularly useful because digested nutrients pass into the villi.

This increased surface basically means that the distance travelled by nutrient molecules is decreased, hence allowing for more efficient absorption of nutrients.

- lacteal enables diffusion of fatty acids

dense capillary network = large blood supply = easier diffusion

enzymes

Substances

tests

Villi and bile