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level: Level 1 - Definitions

Questions and Answers List

level questions: Level 1 - Definitions

Question	Answer
The whole passage along which food passes, from mouth to anus.	Alimentary Canal
The taking of food into the alimentary canal.	Ingestion
The removal of undigested food through the anus.	Egestion
The undigested material remains after digestion of food in humans.	Faeces
The mechanical breakdown of large food pieces. eg chewing and by stomach muscles.	Physical Digestion
The enzymatic breakdown of large insoluble molecules into small soluble ones.	Chemical Digestion
A substance that increases the rate of a chemical reaction, such as an enzyme.	Catalyst
A protein that acts as a biological catalyst.	Enzyme
The area of an enzyme where the substrate binds and the products are formed.	Active Site
When a biological molecule loses it's 3D structure. Can occur via high temperature or change in pH.	Denaturing
A liquid produced by the liver and stored in the gall bladder, which is highly alkaline and emulsifies lipids.	Bile
Break up large droplets of lipids in an aqueous solution into smaller droplets.	Emulsify
A plant material that is difficult to digest, keeping food in the alimentary canal soft, bulky, aiding peristalsis.	Fibre
Waves of muscular contractions that pushes food along the alimentary canal.	Peristalsis
Releasing chemicals that have been made inside the cell into the fluid outside the cell.	Secretion
A toxic substance produced in the liver from the breakdown of amino acids not needed in the body.	Urea
Finger-like projections of the small intestine wall where absorption of digested food molecules occurs.	Villi
Tiny finger-like extensions of the cell membrane on the surface cells of villi.	Microvilli
Type of molecule which contains carbon atoms. (NB there are exceptions such as carbon dioxide).	Organic
Large organic molecules made of many amino acids, eg found in muscle cells.	Proteins
The basic unit of a protein.	Amino Acid
An organic molecule, eg starch or glycogen	Carbohydrate
A single unit of sugar such as glucose. Cannot be broken down into an even simpler sugar.	Monosaccharide
A large organic molecule, insoluble in water, but soluble in ethanol. eg triglycerides, olive oil and ear wax.	Lipid
The enzyme that digests starch into maltose.	Amylase
The enzyme that digests maltose into glucose.	Maltase
A class of digestive enzymes which digest proteins. eg Trypsin and Pepsin	Protease
An enzyme that digests triglycerides into fatty acids and glycerol.	Lipase