Lecture 7- Metabolism

Question 1

What is anabolism?

Answer 1

Synthesis of complex molecules from simpler ones

Question 2

What is the difference between kinetic energy and potential energy?

Answer 2

Potential energy is the stored energy in an object or system due to its position or configuration, whereas kinetic energy is the energy which a body possesses by virtue of being in motion

Question 3

True or false: Gibbs free energy can be directly measured

Answer 3

False; Gibbs free energy cannot be measured directly

Question 4

How can energy be defined?

Answer 4

The capacity to do work

Question 5

What is adenosine triphosphate (ATP) composed of?

Answer 5

Ribose (pentose sugar), adenine (nitrogenous base), & three phosphate groups

Question 6

What is entropy?

Answer 6

Quantitative measurement of the degree of disorder within a system

Question 7

What do we know about a system if the change in Gibbs free energy is positive?

Answer 7

Reaction is endergonic and nonspontaneous

Question 8

What is a redox reaction?

Answer 8

Reaction in which a substance is reduced and another substance is oxidized (transfer of electrons)

Question 9

What is catabolism?

Answer 9

The breakdown of complex molecules into simpler ones

Question 10

What does the hydrolysis of ATP result in?

Answer 10

Adenosine diphosphate (ADP) & inorganic phosphate

Question 11

What are the first and second laws of thermodynamics?

Answer 11

Energy cannot be created nor destroyed & every transfer of energy increases entropy in the universe

Question 12

What do we know about a system if the change in Gibbs free energy is negative?

Answer 12

Reaction is exergonic and spontaneous

Question 13

What is an enzyme?

Answer 13

Biological catalyst

Question 14

What is Gibbs free energy?

Answer 14

Energy available to do work

Question 15

What do we know about a system if the change in Gibbs free energy is equal to zero?

Answer 15

Chemical processes at equilibrium (rate of forward reaction is equal to rate of reverse reaction)

Question 16

True or false: In competitive inhibition, an inhibitor binds to the allosteric site of an enzyme, preventing the substrate from binding to the active site

Answer 16

False; this is an example of non-competitive inhibition

Question 17

Where in ATP is energy stored?

Answer 17

In the ‘spring-loaded’ phosphoanhydride bonds between phosphates

Question 18

What is a substrate?

Answer 18

Reactant molecule that an enzyme acts upon

Question 19

What process adds phosphate to ADP to form ATP?

Answer 19

Phosphorylation

Question 20

What region(s) of an enzyme can a substrate bind to?

Answer 20

Active site

Question 21

What is a catalyst?

Answer 21

Substance that increases the rate of a chemical reaction by lowering the activation energy, without itself undergoing any permanent chemical change

Question 22

What is NAD+ ?

Answer 22

Coenzyme electron carrier

Question 23

True or false: Enzymes generally function optimally at a certain temperature and pH, which varies amongst different enzymes

Answer 23

TRUE

Question 24

What occurs during competitive inhibition?

Answer 24

Inhibitor binds to enzymatic active site, physically preventing substrate from binding to enzyme

Question 25

What does it mean for a substance to undergo reduction?

Answer 25

Reduction is the gaining of electrons (OIL RIG)

Question 26

What is the difference between cofactors and coenzymes?

Answer 26

Cofactors are generally inorganic (often metals) whereas coeznymes are organic

Question 27

What does it mean for a substance to undergo oxidation?

Answer 27

Oxidation is the loss of electrons (OIL RIG)

Question 28

How does increasing temperature effect enzymatic activity?

Answer 28

Slight increase in temperature can accelerate enzymatic activity but a significant increase in temperature will denature the enzyme and render it useless