Nucleotides And Enzymes Flashcards
Draw and label ATP
Draw and label a DNA nucleotide
State 2 differences between a DNA and RNA molecule
DNA has deoxyribose pentose sugar, whereas RNA has ribose DNA has thymine as a base, whereas RNA has Uracil
– Describe how a nucleotide is formed.
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
– What is the name of the bond that forms between nucelotides
phosphodiester
Describe how DNA replicates
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
– Who discovered the structure of DNA
– Watson and Crick
– Who proved the semi conservative nature of DNA replication
Mehselson and Stahl
DNA strands run antiparallel – what does this mean?
One strand runs 5-3 whereas the other runs 3-5 direction
DNA polymerase can only work in one directionwhat direction is this
Why is that?
5-3
Only has a complimentary fit in that direction
What isotope of N was used as the primer
N15
after one set of replications, how many lines would show on the centrifuged test tube, and at what value
1 at 14.5
What enzymes work INSIDE cells
Intracellular
How do enzymes speed up the rate of reactions
bend bonds in the substrate, lower activation energy
How do you calculate the rate of an enzyme controlled reaction
(volume of product made/reactant used/time taken)
Why does increasing the temperature from 20 to 40 degrees usually speed up an enzyme controlled reaction.
Sub/enzyme molecules have more kinetic energy, more FScollions/more ESC formed,
why does increasing the pH from 7 to 14 usually decrease the rate of reaction.
AS changes shape/denatured, no longer a comp fit, less ESC formed/less FSC
How does an enzyme activator usually wor
changes shape of the active site, makes it more complimentary to substrate, more FSC/ESC form, increases reaction rate
How does a non competitive inhibitor work
- binds to allosteric site/non AS, changes shape of AS, less comp to substrate, less FSC/ESC formed.
How does a competitive inhibitor work?
is similar shape to the substrate, so blocks active site/prevents substrate from bindings/ lowers formation of ESC
Uses of ATP
muscle contraction, active transport, cell division, protein synthesis, DNA replication
What are the purines
Guanine and Adenine
What are the pyrimidines?
Cytosine thymine and uracil
Structural differences between purines and pyrimidines
Purines have 2 rings
Pyrimidines have one
