Biological Molecules

Question 1

What are the 4 major uses of water and the properties that make them possible?

Answer 1

Solvent- polar so can dissolve other polar molecules in it

Transport medium - dissolves stuff, cohesive and adhesive

Coolant- high latent heat of evaporation

Habitat- high specific heat capacity
- less dense when solid = insulating layer

Question 2

What’s the difference between glucose and ribose?

Answer 2

Glucose is a hexose monosaccharide and ribose is a pentose monosaccharide

Question 3

What bonds form between glucose molecules? And how?

Answer 3

Glycosidic bonds through condensation reactions

Question 4

What is sucrose made from?

Answer 4

Fructose and glucose

Question 5

What is lactose made from?

Answer 5

Galactose and glucose

Question 6

What is maltose made from?

Answer 6

2 alpha glucose

Question 7

What is the structure of starch?

Answer 7

Amylose = unbranched and coiled alpha glucose chain - (1,4)
Compact and good for storage

Amylopectin = long and branched alpha glucose chain
(1,6) and (1,4)
Glucose can be released quickly

Question 8

Structure of glycogen

Answer 8

More branching and very compact
- less room to be stored

• released easily and quickly
• insoluble

Question 9

Structure of cellulose

Answer 9

Long unbranched alternating beta glucose

Cross linking chains by hydrogen bonds

Forms microfibrils

Question 10

Structure of triglyceride

Answer 10

1 glycerol molecule
3 fatty acids
Formed by esterfication as Ester bond forms between fatty acid and glycerol

Question 11

Structure of phospholipid

Answer 11

2 fatty acid
1 glycerol
1 phosphate group - rhydrophilic (polar)

Cell membrane

Question 12

What is the general structure of an amino acid?

Answer 12

Central carbon with a carboxyl group, a amine group a hydrogen and a carbon

Question 13

What bonds are formed between amino acids?

Answer 13

Peptide bonds

Question 14

What is the structure and function of haemaglobin?

Answer 14

Conjugated globular protein=
Two a subunits, two b subunits
Prosthetic haem group in each
Soluble

Binds to oxygen and transports in blood

Question 15

Structure and function of insulin?

Answer 15

2 polypeptide chains held together by 3 disulfide bridges
Soluble = transported in blood

Hormone secreted by Pancras that regulates blood glucose level

Question 16

Structure and function of amylase?

Answer 16

Single chain polypeptide
Contains alpha helix and beta pleated

Enzyme that catalyses breakdown of starch

Question 17

Structure and function of collagen?

Answer 17

3 polypeptide chains

Used in connective tissue and is very strong
It binds to minerals to increase ridigity
Every 3rd AA glycine
Held together by h bonds
Strands held together by cross links to form fibrils

Question 18

Structure and function of keratin?

Answer 18

Found in external structures of animals

Flexibility depends on the portion of dulcet containing aa it has cystein

Question 19

Structure and function of elastin?

Answer 19

Elastic connective tissue in skin and blood vessels

Quarterbary protein made of tropoelastin molecules linked together
Coiling

Question 20

How to test for protein?

Answer 20

Biuret test

Add sodium hydroxide 
Add copper(ii) sulfate solution

Blue— purple

Question 21

Test for lipid?

Answer 21

Emulsion test

Shake with ethanol
Pour into water

=milky

Question 22

Test for reducing sugar?

Answer 22

Add Benedicts reagent and heat

Blue — brick red

Question 23

Test for non reducing sugars

Answer 23

Add dilute HCl and heat
add sodium hydrogen carbonate
Add Benedicts reagent and heat

Blue — brick red

Question 24

Test for starch?

Answer 24

Iodine test

Orange — blue/black

Question 25

how does the structure of DNA allow replication?

Answer 25

double stranded ;
each / both (strands) act as template ;
hydrogen bonds , easily , break / form , between
bases ;
complementary (specified) base , pairing / AW ;
purine (only able to) bind to pyrimidine ;
(due to) different sizes of purines and pyrimidines ;
hydrogen bonding different between A & T and C & G
or
3 H bonds between C & G and
2 H bonds between A & T ;

Question 26

what are 3 uses of triglyerides?

Answer 26

Used as a long term energy storage
Protect vital organs
Buoyancy in aquatic animals

Question 27

what is the structural difference between alpha and beta glucose molecule?

Answer 27

in alpha glucose H is above the ring whereas OH is below the ring on carbon one

it is opposite in beta glucose

Question 28

what is lactose permease?

Answer 28

protein that tranpsorts latose across cell suface memrbane