bio molecules

Question 2

properties of water

Answer 2

• as a solvent
• high heat capacity
• as a coolant
• metabolic importance
• cohesion and adhesion

Question 3

water as a polar molecule

Answer 3

oxygen has a greater affinity for the elections and pulls them closer
this results in a weak netgatively charged region on the oxygen atom
weak positively charged region on the H+ atom
oxygen is slightly more negative
hydrogen slightly more positive

Question 4

cohesion and adhesion

Answer 4

the slight negative charge on the 02 atom makes it attract the slight positive + atom of another water molecule and they form a hydrogen bond

Question 5

high specific heat capacity of water

Answer 5

hydrogen bonds require a lot of energy to break them
water less dense than ice so it floats

Question 6

amylose

Answer 6

helical structure
1,4 bonds
carbohydrate storage in plants
compact structure

Question 7

triglycerides

Answer 7

glycerol + 3 fatty acids
form ester bonds

Question 8

sterols

Answer 8

complex alcohol molecules based on 4 carbon ringed structure with a hydroxyl group at one end
position between phospholipids with the OH facing the outside of the membrane
adds stability and regulates the fluidity of the membrane

Question 9

primary protein

Answer 9

sequence of amino acids
only peptide bonds
formed by triplet code in DNA

Question 10

secondary protein

Answer 10

initial folding
hydrogen bonds form
alpha helix - coil
beta pleated sheet - polypeptide chains lie parrallel

Question 11

tertiary structure

Answer 11

folding proteins into final shape
r groups interact
bonds form:
- h+ bonds
- hydrophobic and hydrophilic interactions
- ionic bonds

Question 12

quaternary protein

Answer 12

association of 2 or more proteins called subunits
3D structure
eg haemoglobin

Question 13

globular proteins

Answer 13

soluble in water
metabolic role
spherical
regular and repetitive sequence of amino acids

Question 14

globular protein examples:

Answer 14

Hb:
transports 02
made of 4 polypeptides - 2 alpha and beta subunits + prosthetic group

insulin:
regulates blood glucose
hormones have to fit so have a specific shape

catalase:
enzyme
prevents hydrogen peroxide which damages cells
contains 4 prosthetic haem groups

Question 15

fibrous proteins

Answer 15

lots of hydrophobic groups
insoluble in water
metabolically inactive
long and thin
very specific shape - non repeating sequence of amino acids

Question 16

fibrous protein examples:

Answer 16

collagen:
connective tissue
skin
made of 3 polypeptides wound together in a rope like structure

elastin:
found in elastic fibres
quaternary structure
cross linked structure - flexible
found in lungs - alveoli and blood vessels

keratin:
hair, nails
lots of disulphide bridges
strong