Biochemistry

Question 1

Vmax

Answer 1

The maximal velocity of a reaction

Question 2

Km

Answer 2

The substrate concentration that brings about half Vmax

Question 3

How can you experimentally determine Vmax?

Answer 3

Taking the initial velocities of reactions using known substrate concentrations. Then plot the initial velocities against substrate concentration. The point they plataue off at is almost Vmax.

Question 4

Why is experimentally determing Vmax not effective?

Answer 4

No matter the substrate concentration- the reactions will never reach Vmax.

Question 5

What is the original equation for V and what does it get transformed into?

Answer 5

V= Vmax[S]/km + [S]
1/V = Km+ [S]/ Vmax[S]
1/v= Km/Vmax[S] + [S]/Vmax[S]
1/v= km/Vmax x 1/{S] + 1/Vmax
y=    m                   x   + c

Question 6

What is the gradient of the lineweaver Burke plot?

Answer 6

Km/Vmax

Question 7

What is the y interception?

Answer 7

Vmax

Question 8

What is the x interception?

Answer 8

Km

Question 9

In competitive antagonism- what changes on the Lineweaver Burke plot

Answer 9

Vmax stays the same

Km varies

Question 10

In non-competitive antagonism- what changes on the lineweaver burke plot?

Answer 10

Vmax changes

Km stays the same.

Question 11

Enzymes can have the same Vmax but different Km’s?

Answer 11

True

Question 12

A low Km means

Answer 12

Little substrate is needed to get a half maximal response.

Question 13

A high Km means

Answer 13

Lots of substrate is needed to get a half maximal response.

Question 14

Allosteric enzymes follow the michaelis menten kinetics. True or false

Answer 14

False

Question 15

What sort of curve do allosteric enzymes create?

Answer 15

Sigmoidal

Question 16

What is meant by feedback initiation?

Answer 16

Generally enzymes are in a long chain to make one product. Commonly, once this product has been created it inhibits the rate limiting enzyme in that chain so that there is little substrate available. This limits the reaction.