4

Question 1

1. State two laws of Thermodynamics.

Answer 1

1 Energy is neither created or destroyed, but can be transformed from one form to another. The total amount of energy in the universe is constant. #2 When energy is converted from one form to another, the amount of useful energy decreases.

Question 2

Define energy

Answer 2

The ability to do work

Question 3

Define Entropy

Answer 3

The loss of complexity or orderliness and useful energy results in an increase in randomness, disorder and less useful energy. Entropy is a measure of this randomness.

Question 4

Define Kinetic energy

Answer 4

Energy being used to do work. Ex. Light, sound, movement of atoms and molecules, muscle contraction

Question 5

Define Potential energy

Answer 5

Stored energy availble to do work. Ex. Chemical energy (stored in bonds), concentration gradient.

Question 6

3. Explain endergonic reaction with an example.

Answer 6

Metabolic reactions that require a net input of energy and potential energy is less in reactants than is products. Ex. Co2 and H2o combine to make glucose which has more energy than co2 and h2o. Photosynthesis

Question 7

3. Explain exergonic reaction with examples.

Answer 7

Metabolic reactions that end with a net release of energy and potential energy is more in reactants than in products. Ex. Breakdown of glucose to carbon dioxide and water. Cd and h2o contain less energy than glucose. Cellular respiration.

Question 8

What are coupled reactions?

Answer 8

Simultaneous reactions in which the exergonic reactions provide the energy that drives the endergonic reaction.

Question 9

4. What is activation energy?

Answer 9

Minimum amount of energy needed to get a reaction started.

Question 10

5. List the factors that contribute to the enzyme substrate specificity?

Answer 10

Complementary shape, charge and hydrophilic/hydrophobic characteristics are responsible for this specificity

Question 11

What are enzymes?

Answer 11

Biological catalyst - accelerate a chemical reaction without being consumed. Speed biochemichal reactions by lowering activation energy. Most are proteins, some are RNA

Question 12

6. List the factors that have an effect on enzyme activity.

Answer 12

Temperature, Ph, H bonds (hold enzymes in 3d shape)

Question 13

7. Define metabolic pathway

Answer 13

A series of chemical reactions catalyzed by enzymes and are connected by their intermediates

Question 14

Define Anabolic pathway

Answer 14

The series of chemical reactions that constructs or synthesizes molecules from smaller units, usually requiring input of energy (ATP) in the process.

Question 15

Define Catabolic pathway

Answer 15

A sequence of degradative chemical reactions that break down complex molecules into smaller units, usually releasing energy in the process

Question 16

Define Cyclic pathways

Answer 16

A series of chemical reactions in which the final product is used in the first reaction.

Question 17

8. Explain the mechanisms by which enzyme activity is regulated to control the cells metabolism.

Answer 17

Negative feedback: In noncompetetive inhibition, a sustance binds to an allosteric site changing the enzymes shape. A competetive inhibitor blocks the enzymes active sit. Positive feedbck: A product activates the pathway leading to its own production.

Question 18

9. Understand “redox” reactions

Answer 18

Redox reactions link an exergonic process with an endergonic one. An electron donor would undergo an oxidation reaction, losing energy because this is an exergonic reaction. The molecule simultaneously gaining this electron would be reduced in an ender

Question 19

10. What is electron transfer chain?

Answer 19

Groups of proteins embedded in membranes involved in shuttling electrons. Each protein accepts an electron from the molecule before it and passes it to the next releasing energy in each step. Photosynthesis and cellular respiration.

Question 20

11. Define cofactors

Answer 20

Metal ions or small organic molecules (not protein) that are necessary for enzyme function. (vit and min)

Question 21

Define coenzyme

Answer 21

Organic cofactors. They carry chemical groups/atoms/electrons from reaction to another in metabolic pathways. (NADH, NAD+)

Question 22

Activation energy

Answer 22

Initial energy required in a reaction for the reactants to become products. Ender and exergonic need activation energy.

Question 23

Transition state

Answer 23

Activation energy acts on the bonds of the reactants forcing a change. This change brings on the transition state where the bonds on the reactant molecule reach the breaking point and the reaction will run spontaneously to product.

Question 24

Coupled reactions

Answer 24

Release and store energy in ATP. Potential energy is released when the endmost phosphate group is removed by hydrolysis (exergonic reaction.) Released energy drives an endergonic reaction.

Question 25

Phosphorylation

Answer 25

Cell uses ATP as energy source by transferring phosphate group. 1. Presence of phosphate may energize target molecule making it more likely to bond with other targets. 2. Change shape of target molecule (muscle contraction).