BIOCHEMISTRY

Question 1

INORGANIC COMPOUNDS

Answer 1

1. dont contain carbon element
2. not produced by living organisms
   eg. water, gases and mineral salts

Question 2

ORGANIC COMPOUNDS

Answer 2

1. contain carbon element
2. are produced by living organisms
   eg. carbohydrates, lipids and vitamins

Question 3

INORGANIC COMPOUNDS- functions of water

Answer 3

1. solvent
2. medium in which chemical reactions can occur
3. reagent during hydrolysis (when substances break down it should happen in the presense of water)
4. transporting agent
5. lubricant
6. regulates body temp
7. gives shape and rigidity

Question 4

INORGANIC COMPOUNDS- mineral salts- macroelements deficiency diseases- calcium

Answer 4

humans; rickets, osteomalacia, osteoporosis
plants; weak root growth

Question 5

phosphorus

Answer 5

humans; na
plants; stunted growth

Question 6

sodium

Answer 6

humans; muscle cramps
plants; na

Question 7

potassium

Answer 7

humans; na
plants; yellow and brown leaf margins

Question 8

INORGANIC COMPOUNDS- mineral salts- microelements deficiency diseases- iron

Answer 8

humans; anaemia
plants; chlorosis

Question 9

iodine

Answer 9

humans; goitre

Question 10

phosphates and nitrates are also minerals, but they are not elements, they are compounds.

Answer 10

phosphate ions: na
nitrates ions: protein sysnthesis. nitrogen also forms part of the nucleotides of DNA and RNA, and is needed for synthesis ofd chlorophyll in plants

Question 11

ORGANIC COMPOUNDS: carbohydates

Answer 11

.

Question 12

carbohydrates and made up of ring shaped units

Answer 12

saccharides

Question 13

3 groups according to how many saccharides

Answer 13

monosaccharide; 1
disaccharide; 2
mono and di are sugars because they taste sweet and are water soluble
polysaccharide; 3+
poly are not sugars because they dont taste sweet and are water insoluble

Question 14

monosaccharides

Answer 14

glucose (building block to all carbohydrates)
fructose
galactose

Question 15

disaccharides

Answer 15

condensation reaction - 2 monos are joined and one water molecule is removed
maltose (glucose+ glucose= maltose+ h20)
sucrose (glucose+ fructose= sucrose+h20)
lactose (glucose+ galactose= lactose+h20)

Question 16

polysaccharides

Answer 16

condensation reaction
starch (excess glucose stored in plant)
glycogen (excess glucose stored in humans)
cellulose (structural component of plant cell walls)

Question 17

importance of carbohydrates

Answer 17

1. source of energy
2. source of reserve energy
3. structural component

Question 18

test for carbohydrates- test for glucose

Answer 18

benedicts solution:
1. water bath in heat resistant beaker over bunsen burner
2. pour 5cm3 of benedicts solution into test tube
3. drip 10 drops of test soultion into test tube and place test tube into water bath
4. look at solution after 4 min
5. blue - no glucose present ——- red- glucose present

Question 19

test for starch

Answer 19

1. take test material and drop 2-3 drops of iodine onto it
2. if iodine turns blue/black, starch is present

Question 20

LIPIDS( FATS AND OILS)

Answer 20

1 lipid molecule consists of 1 glycerol molecule and 3 fatty acid molecules

Question 21

lipids are:

Answer 21

1. insoluble in water
2. soluble in ether and alcohol
3. hydrophobic
4. saturated fats- from animals and solid at room temp
5. unsaturated fats- from plants and liquid at room temp

Question 22

importance of lipids

Answer 22

1. source of reserve energy
2. insulating material
3. shock absorption (kidneys and eyes)
4. structural component of cell membranes
5. waterproofing
6. absorption of minerals (A, D, E, K)
7. source of water

Question 23

test for fats

Answer 23

1. grind test material into fine consistency and place small amount into test tube
2. add 5cm3 ether and shake well
3. let stand for 30 min
4. filter ether
5. allow drop of filtrate to fall onto clean filter paper
6. ether will evaporate quickly
7. if fats are present - translucent greasy spot

Question 24

PROTEINS

Answer 24

1. is a polymer with amino acids as monomers

Question 25

bond formed between 2 amino acids= peptide bond

Answer 25

1. dipeptide; 2 amino acids 2. tripeptide; 3 amino acids 3. polypeptide; 4+ 4. protein; 51+

Question 26

proteins are sensitive to?

Answer 26

will denature at high temps and extreme pH levels

Question 27

importance of proteins

Answer 27

1. structural component of protoplasm 2. building materials 3. structual component of cell membranes 4. play role in permeability of cell membranes 5. source of reserve energy 6. hormones regulate processes in body 7. haemoglobin transports o2 and co2 in blood 8. protect body against disease (antibodies are blood proteins 9. chromosomes carry hereditary material 10. act as buffers (keep pH of fluid constant) 11. enzymes control metabolic processes in body

Question 28

test for proteins

Answer 28

1. grind test material into powder, add water and boil until forms soup 2. pour 5cm3 of soup into test tube and add 2-3 drops of diluted copper sulfate soltion (blue) 3. add 7cm3 sodium hydroxide solution(clear) and shake gently 4. heat over bunsen burner to obtain deeper colour 5. blue; no protein present purple; protein present

Question 29

enzymes

Answer 29

enzymes are biological catalysts as they speed up biological chemical reactions they lower the activation energy needed therefore accelerating the reaction

Question 30

chemical reactions that take place inside cell= metabolic reactions. there are 2 types

Answer 30

1. anabolic reactrions 2. catabolic reactions

Question 31

anabolic reactions

Answer 31

energy required simple molecules -> complex molecule

Question 32

catabolic reactions

Answer 32

energy released complex molecule -> simple molecules

Question 33

influence of temp and pH on enzyme action- temp

Answer 33

temporarily inactive in low temps denature at high temps optimum temp= 35-40`c

Question 34

pH

Answer 34

denature at extreme pH levels different enzymes have different optimum pH

Question 35

properties of enzymes

Answer 35

1. spherical proteins 2. substrate specific 3. can be used again and again