Biological Molecules

Question 1

Role of DNA Polymerase

Answer 1

Catalyses condensation reaction that forms phosphodiester bonds joining adjacent nucleotides.
Semi conservative

Question 2

Role of DNA Helicase?

Answer 2

Unwinds DNA helix by breaking double bonds holding strands together

Question 3

How can an enzyme be phosphorylated?

Answer 3

Attachment of phosphate.
By hydrolysis of ATP, ATP —> ADP + Pi

Question 4

Glycosidic bonds form from …

Answer 4

Condensation reaction - removal of H2O

Question 5

How is a disaccharide formed from monomers?

Answer 5

Condensation reaction between two monomers forming glycosidic bond

Question 6

What does ATP Synthase do?

Answer 6

ADP + Pi —> ATP

Question 7

Describe induced fit model of enzyme action.

Answer 7

• substrate binds to active site
• enzyme-substrate complexes formed
  -active site changes shape slightly to become complementary to substrate

Question 8

How does enzyme act as catalyst?

Answer 8

Provides alternate reaction pathway.
Lower activation energy

Question 9

How do you stop reaction involving enzymes?

Answer 9

Heat above 70C or boil.
Denatures enzyme.

Question 10

What could a plateau in a graph about enzyme action represent?

Answer 10

The X component no longer limiting reaction.
All active sites filled , all enzyme substrate complexes

Question 11

Describe the structure of DNA (5mks)

Answer 11

Polymer of nucleotides, each nucleotide formed from phosphate group, deoxyribose and organic base.
Phosphodiester bonds between adjacent nucleotides,
Double helix, two strands, held by hydrogen bonds.
Pairing between ATP and CG

Question 12

Name disaccharide made from two glucose monomers

Answer 12

Maltose

Question 13

Which bond causes helical structure

Answer 13

Hydrogen

Question 14

Define quaternary structure of a protein

Answer 14

More than 1 polypeptide

Question 15

Which monomers is sucrose made from?

Answer 15

Glucose and fructose

Question 16

Which bond between adjacent AA

Answer 16

Peptide bind

Question 17

What is the secondary structure of a protein?

Answer 17

Alfa helix and beta pleats - due to H bonds

Question 18

Which bonds in tertiary structure?

Answer 18

Ionic, hydrogen and disulfide bridges

Question 19

How many condensation reactions to form triglycerides?

Answer 19

3 condensation reactions 3H2O

Question 20

Which bond in unsaturated and not saturated ?

Answer 20

C=C

Question 21

Functions of triglycerides relating to structure …

Answer 21

-Energy storage , lots of C-H bonds in long HC chains, when oxidised during respiration these bonds break to release lots of energy - used to produce ATP, more energy per gram then carbs and proteins.
-Hydroohobic, do not cause osmotic water uptake into cells so more can be stored in cells - plants as oils, Animals as oil droplets in fat.
-protection, fat surrounds organs prevents damaged,
-buoyancy fat has low density
-insulation , component of myelin sheath, insulation causes inc transmission of nerves impulses ,
In fat, insulated against heat loss.

Question 22

Functions of triglycerides relating to structure …

Answer 22

-Energy storage , lots of C-H bonds in long HC chains, when oxidised during respiration these bonds break to release lots of energy - used to produce ATP, more energy per gram then carbs and proteins.
-Hydroohobic, do not cause osmotic water uptake into cells so more can be stored in cells - plants as oils, Animals as oil droplets in fat.
-protection, fat surrounds organs prevents damaged,
-buoyancy fat has low density
-insulation , component of myelin sheath, insulation causes inc transmission of nerves impulses ,
In fat, insulated against heat loss.