IGCSE Biology – Human Nutrition

30 fill-in-the-blank flashcards covering balanced diet, malnutrition, digestion stages, cholera, teeth, dental health, digestive enzymes, bile, stomach acid, and absorption adaptations.

A balanced diet contains carbohydrates, proteins, lipids, vitamins, minerals, dietary fibre and in the correct proportions.

water

The PEM disorder caused by a lack of protein, often giving children a swollen abdomen, is called .

kwashiorkor

The most severe form of protein-energy malnutrition, lacking both protein and energy, is .

marasmus

Ingestion is the taking of substances into the body through the .

mouth

The breakdown of large insoluble molecules into small soluble molecules is known as digestion.

chemical

The movement of digested food molecules through the intestinal wall into the blood is called .

absorption

Vibrio cholerae causes diarrhoea by producing a that stimulates chloride ion release.

toxin

Accumulation of chloride ions in the intestinal lumen lowers the , drawing water out of cells.

water potential

Severe diarrhoea can be treated effectively with oral therapy.

rehydration

Chisel-shaped teeth used for biting and cutting are the .

incisors

Pointed teeth specialised for tearing and holding are the .

canines

Larger flat-surfaced teeth with ridges for grinding are the and molars.

premolars

Bacteria in dental plaque metabolise sugars to produce that dissolve enamel.

acids

Brushing with toothpaste helps strengthen enamel and reduce decay.

fluoride

The carbohydrase that digests starch to maltose is .

amylase

The enzyme that converts maltose to glucose on intestinal membranes is .

maltase

The protease produced in the stomach is .

pepsin

The protease secreted into the duodenum from the pancreas is .

trypsin

Lipase breaks lipids into fatty acids and .

glycerol

Hydrochloric acid in the stomach provides an optimum of about for pepsin activity.

pH 2

Bile is to neutralise the acidic chyme from the stomach.

alkaline

Bile breaks large fat droplets into smaller ones in a process called .

emulsification

Emulsification is an example of digestion, not chemical digestion.

mechanical

Glucose and amino acids are absorbed into the network inside each villus.

blood capillary

Fatty acids and glycerol leave the villus via the .

lacteal

The wall of each villus is cell thick, shortening the diffusion distance.

one

Tiny projections on villus cells that further increase surface area are called .

microvilli

Amylase is produced in both the mouth and the .

pancreas

Most absorption of water takes place in the , though some occurs in the colon.

small intestine

Mechanical digestion in the stomach is achieved by the action of its muscular walls.

churning