Chapter 5 & 6 - The Chemicals of Life & Human Nutrition

Flashcards on The Chemicals of Life, Carbohydrates, Lipids, Proteins, Food Tests, DNA, and Human Nutrition.

Carbohydrates

Includes starch and sugars, made of carbon, hydrogen, and oxygen with a hydrogen to oxygen ratio of 2:1.

Functions of Carbohydrates

Energy, storage (starch in plants, glycogen in animals), and cellulose for plant cell walls.

Monosaccharide

Basic units of carbohydrates, soluble in water, sweet taste, example: glucose.

Disaccharide

Pairs of simple sugar molecules, soluble in water, sweet taste, example: sucrose.

Polysaccharide

Many mono and disaccharides, insoluble in water, no sweet taste, example: starch/glycogen.

Lipids (Fats)

Composed of carbon, hydrogen, and oxygen. One glycerol molecule attached to three fatty acid molecules. Insoluble in water.

Functions of Fats

Energy (nearly double that of carbohydrates), cell membrane component, insulator, organ protection, and energy store.

Proteins

Long chains of amino acids (20 kinds), containing carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.

Functions of Proteins

Making new cells, tissue repair, antibodies, enzymes, hormones, and hemoglobin (oxygen transport).

Starch Test

Add iodine solution: positive result is blue-black color.

Reducing Sugar Test

Add Benedict's solution and heat: positive result is a color change from blue to green to yellow to orange-red.

Proteins Test

Biuret test: positive result is a purple color.

Fats Test (Ethanol/Emulsion)

Add ethanol, then water: positive result is a milky emulsion.

Vitamin C Test

Add blue dye DCPIP: positive result is decolorization.

DNA

Genetic material making genes and chromosomes, made of two strands of nucleotides coiled into a double helix.

DNA Bases

Adenine (A), Thymine (T), Cytosine (C), Guanine (G). A pairs with T, and C pairs with G.

Balanced Diet

Daily intake of food containing all seven nutrients (carbohydrates, lipids, proteins, vitamins, minerals, roughages, water) in the right proportions.

Dietary Needs

Affected by gender (males need more energy and protein), age (young need protein/energy, babies need calcium/phosphorus/vitamin D), pregnancy/breastfeeding (need protein/vitamins/minerals), and activity (more activity means more energy).