Nucleotides And Enzymes

Question 1

Draw and label ATP

Question 2

Draw and label a DNA nucleotide

Question 3

State 2 differences between a DNA and RNA molecule

Answer 3

DNA has deoxyribose pentose sugar, whereas RNA has ribose DNA has thymine as a base, whereas RNA has Uracil

Question 4

– Describe how a nucleotide is formed.

Answer 4

Base, pentose sugar and phosphate
Condensation reactions
Phosphoester bond between phosphate and sugar/carbon 5 of sugar and phosphate/carbon 1 on sugar and base 2 water molecules made

Question 5

– What is the name of the bond that forms between nucelotides

Answer 5

phosphodiester

Question 6

Describe how DNA replicates

Answer 6

Unwinding of helix by DNA helicase
Breaks H bonds between comp bases
Free nucleotides pair up with the complimentary bases
The free nucleotides bond with phosphodiester bonds
Due to DNA polymerase
Comp pairs form H bonds via DNA ligase

Question 7

– Who discovered the structure of DNA

Answer 7

– Watson and Crick

Question 8

– Who proved the semi conservative nature of DNA replication

Answer 8

Mehselson and Stahl

Question 9

DNA strands run antiparallel – what does this mean?

Answer 9

One strand runs 5-3 whereas the other runs 3-5 direction

Question 10

DNA polymerase can only work in one directionwhat direction is this

Why is that?

Answer 10

5-3
Only has a complimentary fit in that direction

Question 11

What isotope of N was used as the primer

Answer 11

N15

Question 12

after one set of replications, how many lines would show on the centrifuged test tube, and at what value

Answer 12

1 at 14.5

Question 13

What enzymes work INSIDE cells

Answer 13

Intracellular

Question 14

How do enzymes speed up the rate of reactions

Answer 14

bend bonds in the substrate, lower activation energy

Question 15

How do you calculate the rate of an enzyme controlled reaction

Answer 15

(volume of product made/reactant used/time taken)

Question 16

Why does increasing the temperature from 20 to 40 degrees usually speed up an enzyme controlled reaction.

Answer 16

Sub/enzyme molecules have more kinetic energy, more FScollions/more ESC formed,

Question 17

why does increasing the pH from 7 to 14 usually decrease the rate of reaction.

Answer 17

AS changes shape/denatured, no longer a comp fit, less ESC formed/less FSC

Question 18

How does an enzyme activator usually wor

Answer 18

changes shape of the active site, makes it more complimentary to substrate, more FSC/ESC form, increases reaction rate

Question 19

How does a non competitive inhibitor work

Answer 19

• binds to allosteric site/non AS, changes shape of AS, less comp to substrate, less FSC/ESC formed.

Question 20

How does a competitive inhibitor work?

Answer 20

is similar shape to the substrate, so blocks active site/prevents substrate from bindings/ lowers formation of ESC

Question 21

Uses of ATP

Answer 21

muscle contraction, active transport, cell division, protein synthesis, DNA replication

Question 22

What are the purines

Answer 22

Guanine and Adenine

Question 23

What are the pyrimidines?

Answer 23

Cytosine thymine and uracil

Question 24

Structural differences between purines and pyrimidines

Answer 24

Purines have 2 rings
Pyrimidines have one

Question 25

Describe how nucleotides bond

Answer 25

phosphate of one nucleotide (hydroxile group) bonds with deoxyribose sugar (hydroxile group of carbon 3). DNA polymerase does this). Happens via a condensation reaction

Question 26

How are DNA strands separated

Answer 26

DNA helicase unwinds DNA, breaking H bonds between complimentary pairs.

Question 27

– Why should the initial rate of reaction be calculated when conducting enzymes controlled reaction?

Answer 27

As after this, some substrate will be used up, and then will become a limiting factor. Thus, the substrate concentration is no

Question 28

What may you need to draw on your graph to get the initial rate of reaction?

Answer 28

A tangent.

Question 29

whats the name of enzymes that work outside of cells

Answer 29

Extracellular

Question 30

Describe a primary protein

Answer 30

a sequence of amino acids bonded by peptide bonds in a straight chain

Question 31

Describe a secondary protein

Answer 31

folding of primary protein into alpha helix o beta pleated through hydrogen bonds

Question 32

Describe a tertiary protein

Answer 32

Folding of polypeptide chain into a more 3-D structure through ionic bonds, hydrophobic interactions or di-sulphide bonds on the R groups.

Question 33

Describe a quaternary protein

Answer 33

multiple polypeptide chains bonded together,