IGCSE: Human nutrition (copy)

Essential Nutrients

Nutrients necessary for human survival, including carbohydrates, fats, proteins, vitamins, minerals, fiber, and water.

Carbohydrates

Nutrients that provide energy for cellular respiration; sources include rice, pasta, and potatoes.

Fats and Oils

Nutrients that serve as long-term energy stores and provide insulation; sources include cheese, fatty meats, and butter.

Proteins

Nutrients vital for growth and repair of tissues; sources include fish, meat, and eggs.

Vitamin C

A vitamin that maintains healthy skin and gums; deficiency causes scurvy. Sources include citrus fruits.

Vitamin D

A vitamin that helps absorb calcium for strong bones; deficiency leads to rickets. Sources include dairy products and fish oil.

Minerals

Inorganic nutrients essential for various bodily functions, including calcium and iron.

Calcium

A mineral essential for strong bones and teeth; aids in blood clotting. Sources include milk and cheese.

Iron

A mineral necessary for hemoglobin in red blood cells, carrying oxygen. Sources include red meat and spinach.

Fiber (Roughage)

A nutrient that aids in moving food through the digestive system; sources include vegetables, fruits, and whole grains.

Water

An essential nutrient required for chemical reactions in cells; sources include plain water and beverages.

Digestive System

The system that breaks down food into smaller molecules for nutrient absorption; includes the mouth, esophagus, stomach, small intestine, and large intestine.

Ingestion

The process of taking food and drink into the body.

Digestion

The breakdown of food into smaller, absorbable molecules, which includes physical and chemical digestion.

Absorption

Movement of nutrients from the intestines into the bloodstream.

Assimilation

The uptake and use of nutrients by cells.

Ejection

The removal of undigested food as feces.

Physical Digestion

The mechanical breakdown of food into smaller pieces without changing its chemical structure.

Chemical Digestion

The enzymatic breakdown of large molecules into smaller, soluble molecules.

Amylase

An enzyme that breaks down starch into sugars, acting in the mouth and duodenum.

Protease

An enzyme that breaks down proteins into amino acids, active in the stomach and small intestine.

Lipase

An enzyme that breaks down fats into fatty acids and glycerol, acting in the duodenum.

Hydrochloric Acid

An acid found in gastric juice that kills harmful microorganisms and provides an acidic environment for enzyme activity.

Bile

A substance produced by the liver that emulsifies fats and neutralizes stomach acid.

Ileum

The final section of the small intestine, designed for nutrient absorption with a highly folded surface and villi.

Villi

Small finger-like projections in the intestine that aid in nutrient absorption into the bloodstream and lymphatic system.