Bio molecules

Question 1

Metabolism

Answer 1

collective chemical processes that take place in an organism

Question 2

What is maltose composed of?

Answer 2

2 glucose

Question 3

What is sucrose composed of?

Answer 3

glucose + fructose

Question 4

What is lactose composed of?

Answer 4

glucose + galactose

Question 5

Structure + function of glycogen

Answer 5

• highly branched so hydrolysed rapidly -> cope w/ higher metabolic rate of animals
• insoluble so doesn’t affect water pot.
• compact -> stored in small space
  => storage of glucose in animals

Question 6

Structure + function of cellulose

Answer 6

• long straight microfibrils run in parallel creating H bonds between molecules -> strength + rigidity of plant cell wall
• B glucose alternately rotated 180 creating glycosidic bonds 1’ and 4’ C atoms -> resist osmotic pressure + digestion by enzymes
  => strengthening + maintaining structure of cell wall

Question 7

Structure + function of starch (amylopectin + amylose)

Answer 7

• amylose has compact helical structure -> efficient storage
• amylopectin is branched -> easily hydrolysed
• insoluble -> doesn’t affect water pot.
  => storage of glucose in a plant

Question 8

Test for reducing sugar

Answer 8

Benedict’s solution + heat

blue -> orange/brown if present

Question 9

Properties of phospholipids

Answer 9

• polar molecule -> in aq. environments forms a bilayer
• hydrophilic phosphate group helps hold molecule at surface of cell membrane
• forms glycolipids w/carbs -> cell recognition

Question 10

Properties of triglycerides

Answer 10

• high ratio of energy storing C-H bonds
• low mass:energy ratio -> gd for storage
• insoluble, large -> no effect on water pot.
• release water when oxidised

Question 11

Test for lipids

Answer 11

Ethanol and boil
Add distilled water

white emulsion if present

Question 12

Composition of amino acid

Answer 12

• central C atom
• amino group NH2
• carboxyl group COOH
• side chain (R) varies in shape polarity + charge

Question 13

Primary structure of protein

Answer 13

Sequence of amino acids joined by peptide bonds to form polypeptide chain

Question 14

Secondary structure of protein

Answer 14

Folding of polypeptide into alpha helix or beta pleated sheet
- held in place by H bonds between NH and C=O of adjacent amino acids

Question 15

Tertiary structure of protein

Answer 15

Further folding + formation of new bonds eg, H bonds, disulphide bridges, ionic bonds
R group determines these

Question 16

Quaternary structure of protein

Answer 16

2 or more polypeptide chains are bound together - can contain prosthetic group

Question 17

Fibrous proteins

Answer 17

eg collagen

• structural function
• strong inter. forces
• sheet like structure
• insoluble

Question 18

Globular proteins

Answer 18

eg. enzymes, haemoglobin
- metabolic functions
- weak inter. forces
- 3D ball like structure
- soluble

Question 19

Induced fit hypothesis

Answer 19

Change in shape of enzymes active site induced by substrate -> fully complimentary after binding

Question 20

Activation energy

Answer 20

Minimum amount of energy needed by particles in a collision to cause a reaction

Question 21

Competitive inhibition

Answer 21

Inhibitor has complimentary shape to active site -> competes w/ substrate reducing no. of ES complexes formed

Question 22

Non-competitive inhibition

Answer 22

Inhibitor binds to enzyme changing the shape of the active site preventing any ES complexes from forming

Question 23

Factors affecting enzyme rates of reactions

Answer 23

• temperature
• pH
• conc. of substrate
• conc. of enzyme
• inhibitors

Question 24

Difference between alpha and beta glucose

Answer 24

• OH bottom right in alpha, top right in beta
• alpha forms glycogen + starch
• beta forms cellulose

Question 25

Test for non reducing sugar

Answer 25

• heat solution w/ acid + neutralise
• add benedict’s + heat
• if blue -> orange/brown then non-reducing sugar present

Question 26

Ester bonds

Answer 26

Form in condensation reaction btw. glycerol + f.acid

Question 27

Peptide bonds

Answer 27

Form in condensation reaction btw. carboxyl + amino group

Question 28

Test for starch

Answer 28

Iodine

orange/brown to blue/black if present