Chapter 6

Question 1

What is the FIRST Law of Thermodynamics?

Answer 1

*“Law of conservation of energy”
*Energy cannot be created or destroyed, but can be transformed from one type to another

Question 2

What is the SECOND Law of Thermodynamics?

Answer 2

Transferring from different kinds of energy will increase how disordered (entropy, jumbled all around) the system is and as this disorder (entropy) increases there is less energy to be used in organisms for change

Question 3

Kinetic Energy VS Potential Energy

Answer 3

Kinetic-associated with movement
Potential- due to structure or location

Question 4

H=G+TS
Explain what each letter means

Answer 4

H = enthalpy or total energy
G = free energy or amount of energy for work
S = entropy or unusable energy
T = absolute temperature in Kelvin (K)

Question 5

Exergonic VS Endergonic

Answer 5

Exergonic = spontaneous
Energy is released by reaction
Endergonic = not spontaneous
Requires addition of energy to drive reaction

An endergonic reaction can be coupled to an exergonic reaction

Question 6

How does ATP Hydrolysis work?

Answer 6

*Reaction favors formation of products
*The energy liberated is used to drive a variety of cellular processes

Question 7

*****Describe how cells use the energy released by ATP hydrolysis to drive endergonic reactions. (Coupled reactions)

Question 8

Catalyst

Answer 8

an agent that speeds up the rate of a chemical reaction without being consumed during the reaction

Question 9

Enzymes

Answer 9

protein catalysts in living cells
They play a role in all functions of metabolism, i.e breaking up foods into forms that are more easily absorbed by the body.

Question 10

Ribozymes

Answer 10

R N A molecules with catalytic properties

Question 11

Activation Energy

Answer 11

*Initial input of energy to start a reaction
*Allows molecules to get close enough to cause bond rearrangement
*Can now achieve transition state where bonds are stretched

Question 12

What are some common ways to overcome activation energy?

Answer 12

Large amounts of heat
Using enzymes to lower activation energy

Question 13

How do enzymes lower activation energy?

Answer 13

*Straining bonds in reactants to make it easier to achieve transition state
*Positioning reactants together to facilitate bonding

Question 14

Active Site

Answer 14

location where reaction takes place

Question 15

Substrates

Answer 15

reactants that bind to active site

Question 16

Enzyme-substrate complex

Answer 16

formed when enzyme and substrate bind

Question 17

TRUE or FALSE– Enzymes have a low specificity for their substrate

Answer 17

FALSE. Have a high specificity
Lock and key metaphor for substrate and enzyme binding – only the right key (substrate) will fit in the lock (enzyme)

Question 18

What are some Enzyme reactions?

Answer 18

Affinity – Degree of attraction between an enzyme and its substrate
Saturation - Plateau where nearly all active sites are occupied by substrate
Michaelis constant- Substrate concentration where velocity is half maximal value

Question 19

Competitive VS. Noncompetitive VS. Irreversible Inhibition

Answer 19

Competitive inhibition-
Molecule binds to active site
Inhibits ability of substrate to bind
Noncompetitive inhibition-
Inhibitor binds to allosteric site, not active site
Irreversible inhibition-
Usually bind covalently to an enzyme to inhibit its function
Not a common way for cells to control enzyme function

Question 20

The RNA is a true catalyst
TRUE or FALSE

Answer 20

TRUE

Question 21

Catabolic Pathways VS. Anabolic Pathways

Answer 21

Catabolic pathways-
Breakdown cellular components
Exergonic
Complex–>Simple
Anabolic pathways-
Synthesis cellular components
Endergonic
Must be coupled to exergonic reaction
Simple–>Complex

Question 22

Where do Chemical Reactions occur?

Answer 22

Metabolic pathways

Question 23

Catabolic Reaction

Answer 23

Breakdown of reactants
Used for recycling building blocks
Used for energy to drive endergonic reactions
Energy stored in intermediates such as ATP, NADH
Example: Breakdown of glucose into two molecules of pyruvate during glycolysis; ATP is produced

Question 24

What are the 2 ways to make ATP and describe them

Answer 24

Substrate-level phosphorylation-
Enzyme directly transfers phosphate from one molecule to another molecule
Chemiosmosis-
Energy stored in an electrochemical gradient is used to make A T P from A D P and Pi

Question 25

Redox Reaction

Answer 25

Electron removed from one molecule is added to another

Question 26

Oxidation VS. Reduction

Answer 26

O- Removal of Electrons
R- Addition of Electrons

Question 27

In what 2 ways is NADH useful?

Answer 27

Releases a lot of energy when oxidized that can be used to make A T P
Can donate electrons during synthesis reactions to energize them

Question 28

Anabolic Reactions

Answer 28

Biosynthetic reactions
Make large macromolecules or smaller molecules not available from food
Require energy inputs from intermediates (N A D H or A T P) to drive reactions

Question 29

What are the ways you can regulate metabolic pathways?

Answer 29

Gene regulation - Turn genes on or off
Cellular regulation - Cell-signaling pathways like hormones
Biochemical regulation - Feedback inhibition – product of pathway inhibits early steps to prevent over accumulation of product
Regulation of the rate-limiting (slowest) step – If the rate limiting step is inhibited or enhanced, such changes will have the greatest influence on the pathway

Question 30

Proteases

Answer 30

cleave bonds between amino acids

Question 31

Proteasome

Answer 31

A large complex that breaks down proteins using protease enzymes

Question 32

Autophagy

Answer 32

recycling worn out organelles using an autophagosome

Question 33

Delta G

Answer 33

equals negative 7.3-kilo calorie over the molecule

Question 34

Once ATP donates its phosphate in a coupled reaction it becomes ADP. ADP + inorganic phosphate can be combined back to ATP only if this reaction is coupled with a/n ____ reaction.

Answer 34

Exergonic

Question 35

A bowl of sugar water is very stable. But if you feed it to cells it is rapidly broken down into carbon dioxide and water. What is the best explanation for this observation?

Select one:
a.
Glucose cannot be broken down outside a cell.
b.
Glucose becomes more chemically reactive inside a cell.
c.
Pyruvate is more stable inside the cell.
d.
Glucose is removed from the cell by active transport.
e.
Enzymes in the cell catalyze the breakdown of glucose.

Answer 35

E

Question 36

Water held behind a dam would best reflect ______.

Answer 36

Potential Energy

Question 37

What does an enzyme do to increase the rate of a chemical reaction? (be specific)

Answer 37

Lowers activation energy

Question 38

An autotroph captures energy from other sources and does not actually produce energy because ____.

Answer 38

Energy cannot be created or destroyed