2a. Organisation: Digestion and enzymes key words

Absorption

The uptake of molecules from one place into another.e.g. absorption of glucose from the digestive system into the bloodstream

(by active transport) or the uptake of water from the soil into the roots (by osmosis).

Active site

The part of an enzyme where the substrate is able to bind.The shape of the substrate and active site have to be complimentary.

Amylase

An enzyme that is able to digest starch into sugars.

Bile

A chemical secreted by the liver that emulsifies fat into tiny droplets in the duodenum.

Carbohydrate

A group of molecules including sugars and starch and glycogen.

Sugars are used in respiration to release energy.

Starch and glycogen are stores of energy.

Denatured/ denature

When the shape of the active site of an enzyme is changed and is no longer able to bind to the substrate.The reaction will stop. Extremes of pH and temperature will cause this.

Digestion

The breakdown of larger soluble molecules into smaller soluble ones followed by their absorption into the blood.

Duodenum

The region of the small intestine where most digestion by enzymes occurs.

Emulsification/Emulsified

Where lipids are broken into tiny droplets.This increases their surface area so that more lipase can attach and break

down the lipid more quickly.

Enzyme

Biological catalyst made of protein: able to speed up chemical reactions without being used up. They are specific for a particular substrate due to their shape.

Gland/ glandular

A tissue that is able to secrete chemicals (e.g. mucus or enzymes).

Ileum

The region in the small intestine where digested food is absorbed into the blood. Has many Villi to increase the S.A.

Large intestine (colon)

Where water is absorbed in the blood from the intestines.

Lipase

Enzymes that digest (break down) lipids into fatty acids and glycerol.

Lipid

Molecules made from 3 fatty acids and glycerol. Used to store energy.

Muscle

Tissue that is able to contract to cause movement (e.g. churning of food in the gut).

Optimum

The conditions where an enzyme will function at its highest rate. Enzymes have an optimal pH and temperature.

Organ

A group of tissues working together to perform a function. Eg. The heart pumping blood around the body

Organ system

A group of organs and associated tissues working together to perform a function.

Pepsin

An enzyme that can digest protein into amino acids.

Peristalsis

The rhythmic contraction of muscles in the walls of the intestine that move food through the intestine or churn food in the stomach.

Proteins

Large polymers (polypeptides) made of amino acids.Have a structural of functional role depending on their structure.

Stomach

A muscular bag in the intestines that churns food and digests proteins.Contains Acid and the enzyme pepsin

Tissue

Groups of the same type of specialised cells working together to perform a function.