Chapter 9

Question 1

Catabolic Pathways for Energy Production

Answer 1

Catabolism: Breakdown of complex molecules to simpler ones. Releases energy.

Question 2

Fermentation

Answer 2

A catabolic process. A partial degradation of sugars/other organic fuel that occurs without the use of oxygen. ANAEROBIC RESPIRATION

2 types:
1. Alcohol fermentation-pyruvate is converted into ethanol (ethyl alcohol) in 2 steps. Release CO2 from pyruvate, turns into acetaldehyde. Reduced by NADH to become ethanol. Regenerates supply of NAD+.
2. Acid fermentation-(lactic acid) pyruvate is reduced directly by NADH to form lactate as an end product, regenerating NAD+ w/ no release of CO2.

Question 3

(Aerobic) Cellular Respiration

Answer 3

Most efficient catabolic pathway. Oxygen is consumed as a reactant along with the organic fuel. Cells of most eukaryotic and many prokaryotic organisms can do this.

Question 4

(Anaerobic) cellular respiration

Answer 4

Some PROKARYOTES use substances other than oxygen as reactants in a similar process that harvests chemical energy w/out oxygen.

Question 5

Cellular Respiration

Answer 5

Includes both aerobic and anaerobic processes. Generally used to reference the aerobic process.

Question 6

Balanced equations for respiration

Answer 6

C6H12O6(Glucose/organic compound) + 6 O2 (oxygen) -> 6 CO2 + 6 H2O + Energy (ATP + Heat).

Produces: Delta G= -686kcal/mol

Question 7

Photosynthesis and Chemical Coupling

Answer 7

Products of Light Reactions: used in Calvin cycle.

Products of Calvin cycle: used in Light Reactions

Question 8

Oxidation and reduction (redox) reactions

Answer 8

Redox Reactions: In many chem. reactions, there is a transfer of one or more electrons from one reactant to another. Also called oxidation-reduction reactions.

Question 9

Oxidation

Answer 9

The loss of electrons from one substance during a redox reaction. Fig 9.2

Question 10

Reduction

Answer 10

The addition of electrons to another substance during a redox reaction. (Adding a negatively charged electron to an atom REDUCES the amount of positive charge) Fig 9.2

Question 11

“Reducing agent” (Oxidation + Reduction reactions)

Answer 11

It is the electron donor during a redox reaction. Fig 9.2

Question 12

Oxidizing Agent (Oxidation and reduction reactions)

Answer 12

The electron accepter in a redox reaction. Fig. 9.2

Question 13

Glyceraldehyde 3-phosphate

Answer 13

Glucose ->G3P(x2) -> Pyruvate(1 each). From G3P -> Pyruvate, 1 NADH+H+ and 2 ATP produced.

Question 14

Process of Harvesting Energy

Answer 14

Cannot be harvested all at once. i.e. gas explosion. Glucose is broken down in a step by step process, each one catalyzed by an enzyme. At key steps, electrons are stripped from the glucose. Electrons don’t travel alone, need proton. Become hydrogen. Hydrogens not transferred directly to O2, but usually passed first to electron carrier, called nicotinamide adenine dinucleotide (NAD).

Question 15

NAD+-> NADH + H+

Answer 15

NAD+ is an electron accepter. Fig 9.3 Reduced form = NADH. Enzymes called dehydrogenases remove a pair of hydrogen atoms from the substrate, thereby oxidizing it. Enzymes delivers the 2 electrons along with 1 proton to its coenzyme, NAD+, forming NADH. The other proton is released as a hydrogen ion (H+) into the surrounding solution.

Question 16

Overview of Cellular Respiration

Answer 16

1. Glycolysis (Using 1 glucose): Produces 2 pyruvic acid molecules (pyruvate) formed + ATP. 2 NADH+H+

1.1 Pyruvate Oxidation: produces 1 NADH+H+ and a CO2.

2.1 Fermentation (Using 1 pyruvate): Produces 2 NAD+ and eithrr an Acetic, propionic, lactic acid or an ethanol.

2.2 Krebs cycle: using Acetyl CoA, produces 1 ATP, 1 FADH2, 3 NADH+H+, and 2 CO2.

3. Oxidative Phosphorylation: ETC, produces a lot of ATP.

Question 17

Glycolysis

Answer 17

First step in the Krebs cycle. Involves one glucose + 2 ATP eventually leads to 2 3C + P from an ATP. (Pyruvic acid). Leads to 2 cycles of Krebs cycle. Requires 2 ATP, produces 4 ATP, 2 NADH+H+, and 2 pyruvate. ATP produced via SLP.

Question 18

Krebs (Citric Acid) Cycle

Answer 18

Glycolysis->Krebs cycle. Krebs cycle requires pyruvic acid, which becomes acetyl Coenzyme A (2C). Combines with Oxaloacetic Acid (4C) to form Citric acid (6C). Go to notes, hard to verbalize. NAD+ becomes NADH+H+ 3 times per cycle. One FAD to FADH2. Releases 2 CO2. 1 ATP. Eventually cycles back to becoming Oxaloacetic acid.

Question 19

Oxidative Phosphorylation

Answer 19

A cellular process that harnesses the reduction of oxygen to generate high-energy phosphate bonds in the form of adenosine triphosphate (ATP).

Question 20

Fermentation

Answer 20

Pyruvic acid -> Ethanol, Lactic acid, Propionic acid, acetic acid. All of them involving NADH + H+ -> NAD+

Question 21

Glycolysis and Krebs cycle connection to other metabolic pathways

Answer 21

All fats, proteins and sugars join in glycolysis/krebs cycle somewhere

Question 22

Electron Transport Chain

Answer 22

A collection of molecules embedded in the inner membrane of the mitochondrion in eukaryotic cells. (In prokaryotes, these molecules reside in the plasma membrane.)

Question 23

Negative feedback mechanisms

Answer 23

A product at the end of a chain inhibits the production of the earliest step of production, unless prodded to do otherwise.

Question 24

Amount of ATP produced by NADH+H+ in ETC

Answer 24

2.5 ATP (Some round up to 3 ATP)

Question 25

Amount of ATP produced by FADH2 in ETC

Answer 25

2 ATP

Question 26

Pyruvate to Acetyl

Answer 26

Pyruvate Oxidation Pyruvate is in the cytosol. Acetyl (2C) is in the mitochondrial matrix. Helps produce 1 NADH+H+ and releases a CO2. Combines with CoA to meet up with the oxaloacetate (4C). Combine to form Citric acid (6C), release CoA. In total: Produces 1 NADH+H+, 1 CO2 and 1 acetyl CoA (Happens twice per glycolysis).

Question 27

Coenzyme and Vitamin Needed

Answer 27

NAD-Niacin, B3
FAD-Riboflavin, B2
CoA-Pantothenic Acid, B5

Question 28

SLP

Answer 28

Substrate Level Phosphorylation. Phosphate group comes from a different organic molecule.

Question 29

Last ETC Receptor

Answer 29

OXYGEN. 1/2O2+2e-+2H+

Question 30

Chemiosmosis

Answer 30

Using the electron gradient (H+ ions in the mito. intermembrane space)+ ATP synthase (Protein) = ATPs.

Question 31

NADH+H+ vs. FADH2

Answer 31

NAD has a lower affinity for H+ ions so it drops it off in I protein of the ETC. FADH2 drops it off into II protein of the ETC, which has a lower free energy resulting in less protons being pushed into the mito. intermembrane space. Resulting in less ATP being produced.