UNIT 1: Nutrition

Question 1

Common elements in food

Answer 1

Carbon (C)
Hydrogen (H)
Oxygen (O)
Nitrogen (N)
Phosphorus (P)
Sulphur (S)

Question 2

Elements in foods as dissolved salts

Answer 2

Sodium (Na)
Magnesium (Mg)
Calcium (Ca)
Potassium (K)
Chlorine (Cl)

Question 3

Trace elements

Answer 3

Iron (Fe)
Copper (Cu)
Zinc (Zn)

Question 4

Biomolecules

Answer 4

Chemicals found in and produced by living organisms
Carbohydrates
Lipids
Proteins
Vitamins

Question 5

Carbohydrates

Answer 5

C,H,O: Cx(H20)y
Monosaccharides
Disaccharides
Polysaccharide (CH20)n

Question 6

Monosaccharides

Answer 6

Glucose [C6H12O6] - a reducing sugar and formed by the breakdown of glycogen.
Fructose [C6H12O6] - a reducing sugar and found in many fruits.
Galactose [C6H12O6] - a reducing sugar and formed by the breakdown of lactose.

Question 7

Disaccharides

Answer 7

Maltose (a reducing sugar) - found in germinating seeds e.g. barley.
- glucose + glucose = maltose [C12H22O11] +H2O.
Sucrose (NOT a reducing sugar) - table sugar.
- glucose + fructose = sucrose [C12H22O11] +H2O.
Lactose (a reducing sugar) -found in milk.
- glucose + galactose = lactose [C12H22O11] +H2O

Question 8

Polysaccharides

Answer 8

Starch (amylose) - plants store glucose as starch e.g. potatoes, bananas.
-Long chains and some branching of glucose molecules making it easy to digest.
Cellulose (fibre / roughage) - found in cell walls and stems of plants e.g. celery.
- composed of many glucose molecules bonded together in long chains making it difficult to digest.
Glycogen - animals store glucose as glycogen in liver and muscles.
- more branched than starch

Question 9

Structural & metabolic role of carbohydrates

Answer 9

Structural: (cellulose) component of cell walls, keeps plants upright
Metabolic role: (energy) mono-, di-, and polysaccharides are metabolized to release energy

Question 10

Lipids

Answer 10

C,H and O but have fewer O atoms than carbohydrates.

• triglycerides & phospholipids
• food sources: butter, oils, margarine, cream, olives, animal fat

Question 11

Triglycerides

Answer 11

one molecule of glycerol linked to three fatty acid molecules

• fats: solid at room temperature
• oils: liquid at room temperature

Question 12

Phospholipids

Answer 12

one fatty acid replaced by a phosphate

Question 13

Structural & metabolic roles of lipids

Answer 13

Structural role: - Phospholipids: component of cell membranes of all living things.
- Triglycerides: form adipose tissue that surrounds important internal organs and acts as a shock absorber
Metabolic role: - energy: triglycerides are stored by organisms as a source of energy.

Question 14

Proteins

Answer 14

C,H,O and N
Sulfur and phosphorus also present in some proteins
2 main categories:
1. fibrous proteins: little or no folding e.g. protein found in hair, skin, nails.
2. globular proteins - lots of folding e.g. protein hormones, enzymes, antibodies.

Question 15

Structural & metabolic role of proteins

Answer 15

Structural role:
- skin, hair, nails contain keratin.
- muscle composed of actin and myosin.
- bone, ligaments and tendons contain collagen.
Metabolic role:
- enzymes, antibodies, and some hormones are proteins

Question 16

Vitamins

Answer 16

• complex organic substances needed only in small amounts.
• share no common chemical characteristics - all chemically unique.
  A,D,E &K = fat soluble
  B&C = water soluble

Question 17

Structural & metabolic role of vitamins

Answer 17

structural role:
- vitamins do not have any structural role in living organisms
metabolic role:
- homeostasis and normal metabolism

Question 18

Vitamin B9

Answer 18

deficiency:
- spina bifida in children
- anaemia in adults
Metabolic role:
- formation of red blood cells
Sources;
- spinach, egg yolk, sunflower seeds

Question 19

Vitamin D (calciferol)

Answer 19

Deficiency: 
- rickets in children
-osteomalacia in adults 
metabolic role: 
-absorption of calcium in the digestive system 
sources:
- sunlight, eggs, milk

Question 20

Water

Answer 20

• makes up 70-95% of cell mass.
• it is an excellent solvent in which all biochemical reactions occur.
• it participates in chemical reactions e.g. photosynthesis, respiration, digestion, hydrolysis & condensation reactions .
• carries substances around the body of animals and plants.
• carries substances into and out of cells.
• good absorber of heat energy

Question 21

Anabolism

Answer 21

the building up of large biomolecules from smaller biomolecules using energy e.g. photosynthesis, proteinsynthesis.

Question 22

Catabolism

Answer 22

the breaking down of large biomolecules into smaller biomolecules with the release of energy e.g. respiration, digestion

Question 23

Food

Answer 23

Provides the nutrients needed for organisms to get their energy and the materials they require to live