Biochemistry Enzymes And Bioenergy

Question 1

What part of the eukaryotic cell does oxidative and substrate level phosphorylation occur, respectively?

Answer 1

Oxidative phosphorylation happens in the mitochondria, specifically ATP synthase is located along the inner mitochondrial membrane. Substrate level phosphorylation can only happen in the cytosol (glycolysis) or in the mitochondrial matrix (Krebs cycle).

Question 2

Name two methods of phosphoryl group transfer that makes ATP?

Answer 2

Oxidative phosphorylation and substrate level phosphorylation.

Question 3

How does the induced fit model explain enzyme substrate specificity?

Answer 3

The induced fit model posits the idea that the active site is flexible and will change its shape to fit the enzyme. Came after the lock and key model.

Question 4

Is NAD+ the reduced or oxidized form of nicotinamide adenine dinucleotide?

Answer 4

The oxidized form. NADH is the reduced form.

Question 5

What effect does a reduced activation energy have on reaction kinetics?

Answer 5

Increases the reaction rate.

Question 6

How many total electrons can be excepted by 8 molecules of NAD+?

Answer 6

16. Both common electron acceptors NAD+ and FAD can accept 2 electrons per molecule.

Question 7

Enterokinase is an enzyme that converts tripsinogen to tripsin. What is tripsinogen an example for?

Answer 7

Zymogen

Question 8

This is a molecule that always has a biological role of energy and described by having 3 phosphate groups. What is that molecule?

Answer 8

ATP

Question 9

How does a reaction that’s catalyzed by kinase differ than a one catalyzed by phosphatase?

Answer 9

Kinase adds a phosphate group, phosphatase strips a phosphate group.

Question 10

How does a non competitive inhibitor alter the enzyme catalyzed reaction?

Answer 10

Non competitive inhibitor alters the maximum amount you can get. The km is not affected. Non competitive inhibitor inhibits by binding in an area outside the active side (the allosteric site) that causes and a structural change in the active site or the enzyme.

Question 11

What type of chemical reaction closely relates to the biological molecules known as FAD and NAD+?

Answer 11

Oxidation reduction reactions.

Question 12

What single comparison between reactants and products can be made to determine whether the reaction will proceed?

Answer 12

If there is a change in Gibbs free energy, if it’s negative that means it’s a spontaneous reaction. If it’s positive the reaction is non spontaneous.

Question 13

Student analyzes particular physiological reaction and finds that the ^G`=+1.6 From this he will find that the reaction will not proceed spontaneously in the human body. What is the flaw in his assessment?

Answer 13

Standard temperature and pressure don’t apply to the human body.

Question 14

Trace amounts of copper, zinc, magnesium are essential for enzyme cell function. These enzymes are known as

Answer 14

Cofactors

Question 15

How does non competitive inhibitors alter Vmax and Km?

Answer 15

Reduced Vmax and does not affect Km.

Question 16

How does a non competitive inhibitor get affected if we increase the substrate concentration?

Answer 16

Does not get affected

Question 17

While braking bonds is endergonic, hydrolysis of a phosphoanhydride bond is exergonic. What structural features of ATP explain that phenomenon?

Answer 17

Repulsion of the negative charges on the phosphate groups that become stabilized when hydrolyzed with positive ions.

Question 18

How does the lock and key model explain enzyme substrate specificity?

Answer 18

The enzyme substrate complex has a direct fit, there is no flexibility or change in conformation.

Question 19

What happens to the enzyme catalyzed reaction rate when you add more substrate?

Answer 19

Increases and will level off as the reaction becomes saturated. Vmax means that adding extra substrate past this point has no effect.

Question 20

What is a zymogen?

Answer 20

Inactive precursor to a functional enzyme

Question 21

Which one is a zymogen, trepsinogen or trepsin?

Answer 21

Trepsinogen

Question 22

What happens to the equilibrium constant when an enzyme is added to a reaction ?

Answer 22

It does not get affected

Question 23

What is the value called for a reaction rate when the substrate concentration is only at half?

Answer 23

Km (Michaellis Constant)

Question 24

What is the difference between a zymogen and a pro-enzyme?

Answer 24

Same thing, interchangeable.

Question 25

Define what a catalyst is and give an example.

Answer 25

An enzyme that alters the speed or rate of the reaction but does not get used up itself. Coenzymes get used in the reaction.

Question 26

What class of substrates is common to Maltase, sucrase and lactase?

Answer 26

Disaccharides.

Question 27

What is the difference between cofactors and coenzymes?

Answer 27

Cofactors are compounds that are used up for the function of enzymes. A coenzyme is a type of cofactor that is organic like a protein. A cofactors can be inorganic such as ions.

Question 28

A km of a certain reaction is calculated when the substrate concentration is 1.5M. How will that Km change if the concentration is doubled?

Answer 28

It wouldn’t change

Question 29

What is the plot called including Vmax/2 and substrate concentration ?

Answer 29

Michaellis Menten plot

Question 30

For biological redox reactions to proceed spontaneously what should the sign of delta G and E should be?

Answer 30

delta G to be negative and E to be positive. E is the reaction potential.

Question 31

FADH2 is that the reduced or oxidized form of flavin adenine dinucleotide?

Answer 31

The reduced form

Question 32

What name is given to fueling two reactions to make a non spontaneous reaction become spontaneous?

Answer 32

Coupling reaction

Question 33

Phosphofructokinase is a glycolytic enzyme, the inhibition of this enzyme by ATP is an example of what?

Answer 33

Negative feedback

Question 34

Coenzymes that come from food that has to be consumed to work with your enzymes?

Answer 34

Vitamins

Question 35

The name of the plot that has to do with enzyme kinetics (other than Michaellis metten)

Answer 35

Lineweaver Berk plot