Structure and Function of Carbohydrates

Comprehensive vocabulary flashcards covering the structure, types, sources, digestion, and functions of carbohydrates based on the lecture notes.

Carbohydrates

A macronutrient containing carbon (C), hydrogen (H), and oxygen (O) that acts as the primary source of energy in the body.

Monosaccharides

Simple sugars consisting of a single sugar molecule, including glucose, galactose, and fructose.

Disaccharides

Carbohydrates composed of two monosaccharides joined together by a glycosidic bond.

Glycosidic bond

A covalent bond that links two monosaccharides together.

Sucrose

A disaccharide composed of glucose and fructose, sourced from sugar cane, sugar beet, and naturally in fruits and vegetables.

Maltose

A disaccharide composed of two glucose molecules, found in malted grains and cereals.

Lactose

A disaccharide composed of glucose and galactose, found in milk and dairy products.

Oligosaccharides

Large carbohydrate molecules composed of $3$ to $10$ monosaccharide units.

Raffinose

A trisaccharide ($3$ units) composed of galactose, glucose, and fructose, found in legumes, cabbage, and Brussel sprouts.

Stachyose

A tetrasaccharide ($4$ units) composed of $2$ galactose, $1$ glucose, and $1$ fructose, found in legumes and vegetables.

Verbascose

A pentasaccharide ($5$ units) composed of $3$ galactose, $1$ glucose, and $1$ fructose, found in legumes and some seeds.

Polysaccharides

Large carbohydrate molecules composed of more than $10$ monosaccharide units (often hundreds or thousands).

Starch

A polysaccharide made of multiple glucose units that form two types of starch: amylose or amylopectin.

Cellulose

A type of insoluble fibre, described as a non-starch polysaccharide.

Glycogen

A polysaccharide synthesized from glucose in the liver through glycogenesis.

Dextrin

A substance formed during dextrinisation when starchy foods are baked or toasted.

Free sugars

Any sugars added to a food product to enhance its sensory qualities, or intrinsic sugars that are released when fruit is broken down.

Intrinsic sugars

Sugars that occur naturally within the structure of foods, such as in whole fruits or lactose in milk.

Dietary Fibre

An indigestible complex carbohydrate found in plant cell walls that is vital for digestive health.

Soluble fibre

Fibre that forms a gel when dissolved in water, softening and adding bulk to faeces; found in apples, nuts, and oatmeal.

Insoluble fibre

Fibre that does not absorb water and provides bulk to faeces; found in fruit skins, wholewheat bread, rice, and pasta.

Nutrient density

Refers to the amount of vitamins, minerals, and other beneficial nutrients a macronutrient contains relative to its energy (calorie) content.

Carbohydrate energy density

The energy value provided by carbohydrates, measured at a moderate density of $3.75\text{ kcal/g}$.

Glycaemic Index (GI)

A system used to measure how rapidly carbohydrates affect blood glucose levels.

High GI foods

Foods like white bread and sugary items that are digested and absorbed quickly, resulting in a rapid increase in blood glucose levels.

Low GI foods

Foods like wholegrains, fruits, and green vegetables that are digested slowly, causing a slower rise in blood glucose levels.

Villi

Finger-like projections in the small intestine that increase surface area for the faster absorption of monosaccharides.

Blood capillaries

Microscopic vessels in the small intestine with thin, permeable walls that provide a short diffusion distance to transport glucose into the bloodstream.