1.3.2. Write the vitamins а, а biological role and there isfor the reaction

Other Names: Retinol, Retinal, Retinoic acid, Precursors are carotenoids such as beta-carotene

RDA: 900 µg RAE/day, 700 µg RAE/day Upper Level: 3,000 ug/day

Functions: ÷ Vision ÷Maintenance of cornea, epithelial cells, mucous membranes, skin ÷Bone and tooth growth ÷Reproduction ÷Immunity.

Food Source Retinol: fortified milk, cheese, cream, butter, fortified margarine, eggs, liver.

Beta-carotene: spinach and other dark leafy greens; broccoli, deep orange fruits (apricots, cantaloupe) and vegetables (squash, carrots, sweet potatoes, pumpkin)

Deficiency Disease: Hypovitaminosis A

Deficiency Symptoms: ÷Night blindness ÷Corneal drying (xerosis) ÷Triangular gray spots on eye (Bitot’s spots)

÷Softening of the cornea (keratomalacia) ÷Corneal degeneration and blindness (xerophthalmai) ÷Impaired immunity ÷Plugging of hair follicies with keratin, forming white lumps (hyperkeratosis)

Toxicity Disease: Hypervitaminosis A

Chronic Toxicity Symptoms: ÷Increased activity of osteoclasts causing reduced bone density ÷Liver abnormalities ÷Birth defects

Acute Toxicity Symptoms: ÷Blurred vision ÷Nausea, vomiting, vertigo ÷Headaches, increased pressure inside the skull mimicking a brain tumor

витамин А₁ (ретинол)

1.3.3 What are monosaccharides, oligosaccharides and polysaccharides?

Monosaccharides are simple carbohydrates molecules that cannot be broken down into smaller molecules of other carbohydrates. Oligosaccharides are carbohydrates made by bond of between a maximum of 10 monosaccharides. Polysaccharides are polymers of monosaccharides made of more than 10 units of such monomers. The most important polysaccharides are cellulose, starch, glycogen and chitin. Oligosaccharides and polysaccharides are both complex carbohydrates. Their building blocks are the dietary monosaccharides glucose, fructose and galactose, also known as simple carbohydrates, or sugars. Disaccharides such as sucrose, which are composed of two monosaccharide units, are also sugars. The prefix “oligo” means “few.” Most oligosaccharides are composed of three to 10 monosaccharide units. Oligosaccharides are not digestible by human gut enzymes. "Poly” means “many”; polysaccharides are composed of long chains of monosaccharide units. Some are digestible by human enzymes, and some are not.

Monosaccharides - simple sugars with multiple OH groups. Based on number of carbons (3, 4, 5, 6), a monosaccharide is a triose, tetrose, pentose or hexose.

Disaccharides - 2 monosaccharides covalently linked.

Oligosaccharides - a few monosaccharides covalently linked. Another oligosaccharide category are the fructo-oligosaccharides, composed of varying numbers of fructose molecules. They are found in artichokes, onions, garlic, bananas and other foods.

Polysaccharides - polymers consisting of chains of monosaccharide or disaccharide units. Food sources are grains, root vegetables and legumes.