Chapter 6

Question 1

What is thermodynamics?

Answer 1

Branch of chemistry concerned with energy changes

Question 2

What are the two states of energy?

Answer 2

• Kinetic – energy of motion
• Potential – stored energy

Question 3

What is the most convenient way of measuring energy?

Answer 3

Heat

Question 4

How much energy is required to raise 1 gram of water by 1ºC?

Answer 4

1 calorie

Question 5

What does a Calorie with a capital C represent?

Answer 5

A kilocalorie

Question 6

From where does energy flow into the biological world?

Answer 6

The sun

Question 7

What do photosynthetic organisms do with solar energy?

Answer 7

Capture this energy and store it as potential energy in chemical bonds

Question 8

What happens during oxidation?

Answer 8

Atom or molecule loses an electron

Question 9

What happens during reduction?

Answer 9

Atom or molecule gains an electron

Question 10

What are oxidation-reduction reactions also known as?

Answer 10

Redox reactions

Question 11

What does the First Law of Thermodynamics state?

Answer 11

Energy cannot be created or destroyed; it can only change from one form to another

Question 12

What is entropy?

Answer 12

Disorder that is continuously increasing

Question 13

What does the Second Law of Thermodynamics state?

Answer 13

Energy transformations tend to increase the overall entropy of an isolated system, moving it toward a state of greater disorder or equilibrium.

Question 14

What is free energy denoted as?

Answer 14

G

Question 15

What is the equation for free energy?

Answer 15

G = H - TS

Question 16

What does ΔG represent?

Answer 16

Change in free energy

Question 17

What indicates a non-spontaneous reaction?

Answer 17

Positive ΔG

Question 18

What indicates a spontaneous reaction?

Answer 18

Negative ΔG

Question 19

What is activation energy?

Answer 19

Extra energy required to destabilize existing bonds and initiate a chemical reaction

Question 20

How can the rate of an exergonic reaction be increased?

Answer 20

• Increasing energy of reacting molecules (heating)
• Lowering activation energy

Question 21

What are catalysts?

Answer 21

Substances that influence chemical bonds in a way that lowers activation energy

Question 22

What is ATP?

Answer 22

Adenosine triphosphate, chief currency all cells use

Question 23

What are the components of ATP?

Answer 23

• Ribose – 5 carbon sugar
• Adenine
• Chain of 3 phosphates

Question 24

What drives endergonic reactions?

Answer 24

ATP hydrolysis can drive endergonic reactions by coupling the released energy to the energy required for the endergonic process. (exergonic and spontaneous)

Question 25

What are enzymes?

Answer 25

Biological catalysts, most of which are proteins

Question 26

What is the function of the active site in enzymes?

Answer 26

Pockets or clefts for substrate binding

Question 27

What are ribozymes?

Answer 27

Nonprotein enzymes that catalyze reactions in cells

Question 28

What two types of catalysis do ribozymes perform?

Answer 28

* Intramolecular catalysis * Intermolecular catalysis

Question 29

What affects the rate of enzyme-catalyzed reactions?

Answer 29

Concentrations of substrate and enzyme

Question 30

What is a competitive inhibitor?

Answer 30

Substance that competes with substrate for active site

Question 31

What is a noncompetitive inhibitor?

Answer 31

Binds to enzyme at a site other than active site, causing shape change

Question 32

What are allosteric enzymes?

Answer 32

enzymes that can turn on or off depending on whether certain molecules bind to them.

Question 33

What is metabolism?

Answer 33

Total of all chemical reactions carried out by an organism

Question 34

What are anabolic reactions?

Answer 34

Reactions that use energy to build up molecules

Question 35

What are catabolic reactions?

Answer 35

Reactions that harvest energy by breaking down molecules

Question 36

What is feedback inhibition?

Answer 36

when the **final product of a process stops the first step** in that process from happening again. It does this by attaching to an enzyme and **changing its shap**e so it no longer works. This helps the cell avoid making too much of something it already has.