Chapter 13

Question 1

Catabolism

Answer 1

• breakdown of complex molecules into smaller one
• provides energy for anabolism.
• some chemical energy is lost as heat

Question 2

Anabolism

Answer 2

reactions that build molecules and cells

Question 3

Energy

Answer 3

• the ability to do work.
• Chemical energy is present in bonds
• Cells use energy to assemble simple, disordered molecules into complex, ordered forms

Question 4

Entropy

Answer 4

-is a measure of the disorder or randomness of a system (heat)

Question 5

open systems

Answer 5

• obtain energy from their environment
• Energy can be converted from one form to another
• All energy transformation lose some energy as heat

Question 6

photosynthetic microbes

Answer 6

• solar radiation reaches Earth, a small fraction is captured
• Largely in the range of visible light, which can be absorbed by organic molecules

Question 7

energy carriers

Answer 7

• Many of the cell’s energy transfer reactions
• Molecules that gain or release small amounts of energy in reversible reactions
• Examples: NADH and ATP

Question 8

Electron donor

Answer 8

reducing agent, e.g., NADH

Question 9

Electron acceptor

Answer 9

oxidizing agent, e.g., NAD+

Question 10

ATP can transfer energy to cell processes in three different ways

Answer 10

1. Hydrolysis, releasing phosphate (Pi)
2. Hydrolysis, releasing pyrophosphate (PPi)
3. Phosphorylation of an organic molecule

Question 11

Nicotinamide adenine dinucleotide (NADH)

Answer 11

• carries two to three times as much energy as ATP.
• It also donates and accepts electrons.
• NADH is the reduced form.
• NAD+ is the oxidized form.
• NAD+ consumes two hydrogen atoms to make NADH

Question 12

Flavine adenine dinucleotide (FADH2)

Answer 12

• another related coenzyme that can transfer electrons.

- FADH2 (reduced form) versus FAD (oxidized form)

Question 13

Enzymes

Answer 13

• catalyze biological reactions
• Lower the activation energy (Ea) allowing rapid conversion of reactants to products
• Does not change delta G

Question 14

Fermentation

Answer 14

• partial breakdown of organic food without net electron transfer to an inorganic terminal electron acceptor
• do not generate ATP beyond that produced by substrate-level phosphorylation

Question 15

Respiration

Answer 15

complete breakdown of organic molecules to CO2 with electron transfer to a terminal electron acceptor such as O2

Question 16

Photoheterotrophy

Answer 16

catabolism is conducted with a “boost” from light

Question 17

three main routes to catabolize glucose

Answer 17

1. Glycolysis (Embden-Meyerhof-Parnas (EMP) pathway)
2. Entner-Doudoroff (ED) pathway
3. Pentose phosphate pathway (PPP), also known as the pentose phosphate shunt

Question 18

Homolactic fermentation

Answer 18

Produces two molecules of lactic acid

Question 19

Ethanolic fermentation

Answer 19

Produces two molecules of ethanol and two CO2

Question 20

Heterolactic fermentation

Answer 20

Produces one molecule of lactic acid, one ethanol, and one CO2

Question 21

Mixed-acid fermentation

Answer 21

Produces acetate, formate, lactate, and succinate, and others, as well as ethanol, H2, and CO2

Question 22

Swiss cheese production

Answer 22

• involves two fermentation stages:
• Stage 1: Lactobacillus ferments lactose sugar into lactic acid
• Stage 2: bacteria converts lactate to propionate, acetate, and CO2

Question 23

diagnostic microbiology

Answer 23

• important application of fermentation
• To quickly identify the microbe causing a disease and prescribe an effective antibiotic, hospitals use rapid and inexpensive biochemical tests

Question 24

Krebs cycle

Answer 24

• also known as TCA cycle or citric acid cycle
• In prokaryotes, it occurs in the cytoplasm.
• In eukaryotes, it occurs in the mitochondria
• Glucose catabolism connects with the TCA cycle through pyruvate breakdown to acetyl-CoA and CO2

Question 25

Acetyl-CoA

Answer 25

-enters the TCA cycle by condensing with the 4-C oxaloacetate to form citrate

Question 26

For each pyruvate oxidized

Answer 26

• 3 CO2 are produced by decarboxylation.
• NADH and FADH2 are produced by redox reactions
• ATP is produced by substrate-level phosphorylation

Question 27

oxidative phosphorylation

Answer 27

-overall process of the electron transport system (ETS) and ATP generation by the proton motive force (PMF)

Question 28

Aromatic Pollutants

Answer 28

• Many microbes are decomposers in the environment
• Catabolism of aromatic molecules by bacteria and fungi recycles lignin (from wood) and other substances within ecosystems.
• Toxic pollutants are also degraded