2.2 Biological molecules

Question 1

disulfide bond

Answer 1

a covalent bond formed between the sulfur atoms of 2 cysteine molecules

Question 2

water structure: hydrogen bond →

High specific heat capacity

Answer 2

• specific heat capacity is energy to raise the temp of 1 g of a substance by 1C
• hydrogen bonds between water molecules can absorb alot of energy
• water has high specific heat capacity and requires alot of energy to heat up
  → water doesnt experience rapid temp change → good habitat

Question 3

water structure: hydrogen bond →

high latent heat of evaporation

Answer 3

• requires lots of energy to break hydrogen bonds between water molecules
• water has high latent heat of evaporation- alot of energy is used up when water evaporates

Question 4

water structure: polarity → cohesive

Answer 4

• cohesion: attraction between molecules of same type
• water is very cohesive because polariy
  → helps water to flow, good for transporting substances
  → water to transported up plant stems in transpiration steam

Question 5

water structure: polarity → good solvent

Answer 5

• water is polar : slightly (+ve) end of water molecule attracted to (-ve) ion, and the slightly (-ve) end of water molecule attracted to (+ve) ion
• ions get totally surrounded by water molecules
• e.g human: ions dissolve in water in blood

Question 6

water structure: less dense when solid

Answer 6

• water molecules are held further apart in ice bc water molecules form 4 H-bonds to otehr water molecules, → lattice shape
  → ice forms insulating layer on top of water/ water below doesnt freeze, → organism dont freeze, can move around

Question 7

globular protein

Answer 7

• ball shaped

- metabolically active, soluble in water

Question 8

collagen

Answer 8

a fibrous protein in skin, bones, tendons

Question 9

quaternary structure

Answer 9

• 3D shape of a protein molecule made up of 2+ polypeptides

Question 10

structural protein

Answer 10

• has structural role(s) but no means at all

e. g: keratin, collagen

Question 11

fibril

Answer 11

a grouping of several molecules held side-by-side by bonds between them
e.g collagen, cellulose

Question 12

fibre

Answer 12

• a grouping of fibrils of a substance
• large → seen w/ light microscope
• fibrils are of an order of magnitude smaller

Question 13

polysaccharide

Answer 13

molecule of many monosaccharide

Question 14

monosaccharide

Answer 14

sugar of a single sugar unit

Question 15

hexose

Answer 15

a sugar w/ six carbon atoms

Question 16

disaccharide

Answer 16

sugar molecule of 2 sugar units

Question 17

maltase

Answer 17

enzyme catalyses hydrolysis of maltose to glucose

Question 18

amylose

Answer 18

polysaccharide of many a-glucose

Question 19

glycosidic bonds

Answer 19

sugar bond

Question 20

metabolic reactions

Answer 20

chemical reactions in living organisms

Question 21

H-bonds

Answer 21

weak bon between slightly (+ve) and (-ve) charged atom (R-group)

Question 22

latent heat of evaporation

Answer 22

amount of energy absorbed by a substance w/ raising temp, as it changes from states

Question 23

carboxyl group

Answer 23

-COOH

Question 24

amino group

Answer 24

-NH2

Question 25

R group

Answer 25

1/20 possible group of atoms attracts to central C atom in amino acid

Question 26

primary structure

Answer 26

sequence of amino acids

Question 27

secondary structure

Answer 27

a regular, repeating pattern of shape in a polypeptide

e.g a-helix , B-folds

Question 28

tertiary structure

Answer 28

overal 3D shape of protein molecule

Question 29

water structure:

hydrogen bonds → high specific heat capacity

Answer 29

• energy to raise the temp of 1g of a substance by 1C
• H-bonds between water molecules can absorb alot of energy,
  → water doesnt has rapid temp change
  → good habitat

Question 30

water structure

hydrogen bond → high latent of evaporation

Answer 30

• alot of energy to break H-bonds between water molecules
• alot of energy is used up when water evaporates
  → water’s great for cooling things
  → mammals sweat when too hot to release heat

Question 31

water structure

polarity → cohesive

Answer 31

cohesion: attraction between molecules of same type
→ water to flow
→ great for transporting substances
→ water transported up plant stems in transpiration stream

Question 32

water structure

polarity → good solvent

Answer 32

ionic
- water is polar so slightly (+ve) end of water molecule attracted to (-ve) of ion
→ ion totally surrounded by water molecules/ dissolve

Question 33

water structure

less dense when solid

Answer 33

• water molecules are held further apart in ice, forms 4 H-bonds to other water molecules → a lattice
  → in low temp, water forms an insulating layer so water, organism below doenst freeze