Lecture one, biochemistry

Question 1

Write the michaels mentens reaction

Answer 1

v=Vmax[S]/Km+[S]

Question 2

Write the lineweaver-Burk plot

Answer 2

1/V = Km/Vmax X 1/[S] + 1/Vmax

Question 3

· Explain what an enzyme is and what it does

Answer 3

Most enzymes are proteins (but there are RNA enzymes called ribozymes who usually cut and seal DNA/RNA). An enzyme lowers the activation energy for chemical reactions and speeds up the reaction and all without being used up. So after the reaction the enzyme is still here.

Question 4

· Define the different parameters of an enzymatic reaction

Answer 4

Y axis shows reaction rate and X axis shows substrate concentration. Vmax is when the reaction rate equals out even with increased substrate concentration at that given enzyme concentration. Km is half of the reaction rate and also shows the substrate koncentration.

Question 5

· Name outside factors that influence the speed of an enzymatic reaction

Answer 5

pH, temperature, ion concentration, inhibiting factors, substrate concentration.

Question 6

· Explain the concept of allostery

Answer 6

Enzymes can be allosteric which means they have an active site and a regulatory site causing their Vmax and Km graph to look different.

Question 7

· Name the four mechanisms of enzymatic inhibition

Answer 7

The enzyme can be regulated by competitive, noncompetitive and uncompetitive regulators which can completely or partially inactivate the enzyme. Competitive means that the substrate location on the enzyme is blocked by another molecule, non competitive means that the regulatory molecule binds to a regulatory site on the enzyme causing it to change shape and therefore not bind as much or at all to the substrate. Uncompetitive means that the regulatory molecule partially blocks the substrate site. The enzyme can also be regulated and inhibited by its product.