Week 5

Question 1

What is catabolism?

Answer 1

The breakdown of molecules

Question 2

What is catabolism + anabolism?

Answer 2

Metabolism

Question 3

What is the first law of thermodynamics?

Answer 3

Energy cannot be created or destroyed

Question 4

What is letter of the alphabet represents enthalpy?

Answer 4

H

Question 5

What is enthalpy change or delta H?

Answer 5

This is the amount of heat released or absorbed when a chemical reaction occurs at constant pressure

Question 6

What is the second law of thermodynamics?

Answer 6

That the universe tends towards disorder

Question 7

What is the term used to measure disorder?

Answer 7

Entropy (S)

Question 8

Thinking about Gibbs free enrgy…during catabolism is energy being released or does it require energy? What about anabolism?

Answer 8

Catabolism = energy release

Anabolism = requiring energy

Question 9

What is the equation to calculate gibbs free energy? (Delta G)

Answer 9

Change in free energy = change in heat - change in temperature x change in entropy

Question 10

In a exergonic reaction will the gibbs free energy be positive or negative? What about the change in heat?

Answer 10

gibbs free energy = negative value

change in heat = negative value

Question 11

In a endergonic reaction will the gibbs free energy be positive or negative? What about the change in heat?

Answer 11

gibbs free energy = positive value

change in heat = positive value

Question 12

In cells where is chemical energy stored?

Answer 12

In the chemical bonds of organic molecules

Question 13

In relation to the electrons, what is oxidation?

Answer 13

The removal of electrons from an atom

Question 14

In relation to the electrons, what is reduction?

Answer 14

The addition of electrons to an atom

Question 15

What is the type of reaction where oxidation and reduction occur at the same time?

Answer 15

This is a REDOX reaction

Question 16

During oxidation do the number of C-H bonds increase or decrease? What about during a reduction reaction?

Answer 16

Oxidation = C-H bonds decrease

Reduction = C-H bonds increase

Question 17

What are the three energy carriers?

Answer 17

• NADH
• NADPH
• FADH

Question 18

How many electrons will NAD and NADPH carry?

Answer 18

2 electrons

Question 19

What does FAD carry?

Answer 19

• 2 electrons
• 2 hydrogens

Question 20

Which phosphate group carries the most amount of energy in ATP?

Answer 20

The breaking of the first phosphate group

Question 21

What reaction occurs when breaking a phosphate group of ATP?

Answer 21

It is hydolysis

ATP + H₂O –> ADP + Pi + free energy

Question 22

What cofactor/ion does ATP need to work?

Answer 22

Mg₂

Question 23

What do enzymes do?

Answer 23

• catalyse reactions
• provide speed, specificty and control of reactions

Question 24

What are the three reactions that are catalysed by enzymes?

Answer 24

• binding of a substrate
• conversion of bound substrate to bound product
• release of product

Question 25

What do enzymes do to the activation energy?

Answer 25

They lower the activation energy

Question 26

What are cofactors?

Answer 26

They are coenzymes to further facilitate substrate change

Question 27

What are coenzymes made of?

Answer 27

- Metal ions - organic molecules - Vitamins

Question 28

Does the substrate concentration affect the reaction rate?

Answer 28

Yes it does.

Question 29

What is saturation?

Answer 29

This is where all enzyme is bound to the substrate

Question 30

What is V_max?

Answer 30

This is saturation

Question 31

What is Km?

Answer 31

- It is the affinity constant - it is 1/2 V_max

Question 32

If they have a low substrate concentration will they have a high or low affinity?

Answer 32

-they will have a high affinity

Question 33

If there is a high substrate concentration will the enzyme have a low or high affinity?

Answer 33

It will have a low affinity

Question 34

What is the equation to work out the slope of a Lineweaver-Burk Transformation?

Answer 34

Slope = K_m/V_max

Question 35

What is a competitive inhibition?

Answer 35

It is an enzyme that binds to the active site and prevents the substrate from binding

Question 36

What is an uncompetitive inhibitor?

Answer 36

It binds to the enzyme-substrate complex, preventing the release of products

Question 37

What is non-competitive inhibitor?

Answer 37

Binds to a site other than the active site, changing enzyme structure so that normal substrate binding cannot occur

Question 38

What are the two mechanisms that change the conformation of the enzyme?

Answer 38

- allosteric activation and inhibition - conformational changes

Question 39

What is the difference between allosteric and non-allosteric enzymes?

Answer 39

- allosteric will have multiple active sites and non-allosteric will only have one - Allosteric enzymes are sensitve to low concentrations of inhibitors and will regulate metabolic pathways

Question 40

What is feedback inhibition?

Answer 40

This is where the final product will acts as a noncompetitive inhibitor of the first enzyme, which shuts down the pathway