Chapter 6

Question 1

Thermodynamics

Answer 1

Branch of chemistry concerned with energy changes

Question 2

Energy and 2 states

Answer 2

Capacity to do work
1 Kinetic
2 Potential

Question 3

Kinetic energy

Answer 3

Energy of motion (Breaking a bond)

Question 4

Potential energy

Answer 4

Stored energy (form of a bond)

Question 5

Calorie = calorie

Answer 5

Calorie is Kilocalorie
1 Kilocalorie = 1000 calories

Question 6

Metabolism

Answer 6

Total of all chemical reactions carried out by an organism
Metabolism = anabolic + catabolic

Question 7

Anabolic reactions

Answer 7

Use energy to build up molecules (Build monomers into polymers)

Question 8

Catabolic reactions

Answer 8

Release energy by breaking down molecules. Breaking down polymers to make monomers. (starvation = breakdown of muscle)

Question 9

Source of energy on earth

Answer 9

Energy flows into biological world from the sun

Question 10

Photosynthesis

Answer 10

Capture energy (anabolism) and store as potential energy as sugars

Question 11

First law of thermodynamics

Answer 11

Energy cannot be created or destroyed. Energy can only change from one form to another. Total amount of energy in universe remains constant

Question 12

Second law of thermodynamics

Answer 12

Entropy (disorder) is continuously increasing. Energy transformations proceed spontaneously to convert matter from a more ordered/less stable form to a more unstable form

Question 13

G=
H=
T=
S=

Answer 13

G= energy available to do work
H= Enthalpy, energy in a molecule’s chemical bond (Potential energy)
T= Absolute temperature
S= entropy, unavailable energy (disorder)
G = H - TS

Question 14

Positive ΔG

Answer 14

Products have more free energy than reactants.
Endergonic and Anabolic
Requires input of energy
Monomers to polymers

Question 15

ΔG =

Answer 15

Change in free energy
ΔH - TS

Question 16

Negative ΔG

Answer 16

Products have less free energy than reactants (less bonds)
Exergonic and Catabolic
Release excess free energy, spontaneous (But could be slow)
Breaking things, breaking bonds

Question 17

Activation Energy (Ea)

Answer 17

Extra energy required to destabilize an existing bond and initiate a chemical reaction

Question 18

Increase Ea rate 2 ways

Answer 18

Increasing energy of reacting molecules (Heat)
Lowering activation energy

Question 19

Catalyst

Answer 19

Substances that influence chemical bonds in a way that lowers activation energy
Makes reaction proceed faster
Not used up in process
Cannot violate laws of thermodynamics (Endergonic cannot be spontaneous)

Question 20

Enzymes

Answer 20

Biological Catalysts. Work by lowering activation energy.
Mostly proteins. Some RNA called ribozymes

Question 21

ATP Adenosine Triphosphate

Answer 21

Chief currency of the cell
Composed of: Ribose - 5 carbon sugar, Adenine, chain of 3 phosphate groups. Made and used immediately. Travels to where it is needed.

Question 22

ATP, ADP, AMP

Answer 22

Chain of phosphates key to energy storage because bonds are unstable and weak.
Nucleic acid (nucleotide) sugar, nitrogenous base, and phosphate
ATP 3 phosphate
ADP 2 phosphate
AMP 1 phosphate

Question 23

ATP Hydrolysis drives

Answer 23

Endergonic reactions.

Question 24

Coupled reactions of ATP

Answer 24

Energy released by ATP is used immediately by cell for an energy requiring function (Endergonic).

Question 25

Substrate

Answer 25

substance on which the enzyme acts.

Question 26

Active Site

Answer 26

Pockets or clefts for substrates binding.

Question 27

Enzyme and substrate bind forms

Answer 27

Enzyme-substrate complex (tertiary structure). Applies stress to distort particular bonds to lower activation energy. Induced fit/ perfect fit E + S = ES = E + P

Question 28

Coenzymes

Answer 28

When the cofactor is a nonprotein organic molecule. Modified nucleotides are also used. Ex vitamins

Question 29

Cofactors

Answer 29

These can be metal ions that are often found in the active site participating directly in catalysis

Question 30

Inhibitor

Answer 30

Substances that bind to enzyme and decreases its activity

Question 31

Competitive inhibitor

Answer 31

Competes with substrate for active site

Question 32

Noncompetitive inhibitor

Answer 32

Binds to enzyme at a site other than active site (Allosteric site). Causes shape change that makes enzyme unable to bind to substrate

Question 33

Allosteric enzymes

Answer 33

Enzymes exist in active and inactive forms

Question 34

Allosteric inhibitor

Answer 34

Binds to allosteric site and reduces enzyme activity

Question 35

Allosteric activator

Answer 35

Binds to allosteric site and increases enzyme activity

Question 36

Metabolic Pathway or Biochemical Pathway

Answer 36

Chemical reactions that create/store or produce other chemical products for daily function. Reaction occur in a sequence. Product of one reaction is substrate for the next reaction

Question 37

Feedback Inhibition

Answer 37

Metabolic pathways compete for resources. Limits extent of competition. Reaction product or by-product binds to allosteric site of enzyme involved in initial stages. Concentrated product = pathway shut off