sem 2 science revision

Question 1

digestion

Answer 1

: breakdown of food into a form that can be used by an animal. It includes both mechanical digestion and chemical digestion.

Question 2

mechanical digestion

Answer 2

: digestion that uses physical factors such as chewing with the teeth

Question 3

chemical digestion

Answer 3

: the chemical reactions changing food into simpler substances that are absorbed into the bloodstream for use in other parts of the body

Question 4

alimentary canal:

Answer 4

passage from the mouth to the anus. Digestion of food occurs as it moves through the canal.

Question 5

enzymes

Answer 5

: special chemicals that speed up reactions but are themselves not used up in the reaction

Question 6

bolus

Answer 6

: round, chewed-up ball of food made in the mouth that makes swallowing easier

Question 7

peristalsis

Answer 7

: the process of pushing food along the oesophagus or small intestine by the action of muscles

Question 8

villi

Answer 8

: tiny finger-like projections from the wall of the intestine that maximise the surface area of the structure to increase the efficiency of nutrient absorption. Singular = villus.

Question 9

lipases

Answer 9

: enzymes that break fats and oils down into fatty acids and glycerol