Chapter 3 - Metabolism

Question 1

Macronutrients

Answer 1

nutrients needed in large amounts

Question 2

Micronutrients

Answer 2

nutrients needed in small amounts
-trace metals and growth factors

Question 3

Nutrients

Answer 3

supply of monomers (or precursors of) required for cell growth

Question 4

Carbon

Answer 4

bacterial cell is ~50% carbon
heterotrophs use organic carbon
autotrophs use carbon dioxide

Question 5

Nitrogen

Answer 5

proteins, nucleic acids
in nature: ammonia, nitrate (NO3-), nitrogen gas
nearly all microbes use ammonia

Question 6

Phosphorus

Answer 6

nucleic acids and phospholipids

Question 7

sulfur

Answer 7

sulfur-containing amino acids
- cysteine/methionine
vitamins

Question 8

potassium

Answer 8

required for enzymes for activity

Question 9

magnesium

Answer 9

stabilizes ribosomes, membranes, and nucleic acids
- also required for enzyme activity

Question 10

calcium/sodium

Answer 10

required by some microbes
- marine microbes

Question 11

Growth factors

Answer 11

organic compounds required in small amounts in some organisms
- vitamins, amino acids, purines, pyrimidine

Question 12

Vitamins

Answer 12

most frequently required growth factor
- most function as enzymes

Question 13

Active transport

Answer 13

accumulates solutes against concentration gradient
3 classes
- simple transport, group translocations, ABC transporter

Question 14

Simple transport

Answer 14

driven by proton motive force
- symport/antiport

Question 15

symport

Answer 15

solute and protons co-transported in one direction (E. coli lac permease)

Question 16

antiport

Answer 16

solute and proton transported in opposite directions

Question 17

Group translocation

Answer 17

• substance transported is chemically modified
• energy-rich compound drives motion (not proton motive force)

Question 18

Phosphotransferase system

Answer 18

in E. coli
- group translocation
- transport sugars, glucose, mannose, and fructose in

Question 19

ABC transport

Answer 19

ATP-binding cassette
high substrate affinity
requires transmembrane and ATP-hydrolyzing proteins
Gram -: periplasmic binding proteins
Gram +: substrate-binding proteins on external surface of membrane

Question 20

Chemoorganotrophs

Answer 20

conserve energy from chemicals > organic

Question 21

Chemolithotrophs

Answer 21

oxidize inorganic compounds (H2, H2S, NH4+)
- “sulfur” bacteria, “nitrifying” bacteria, “iron” bacteria

Question 22

Phototrophs

Answer 22

convert light into ATP

Question 23

Heterotrophs

Answer 23

obtain carbon from organics

Question 24

Autotrophs

Answer 24

obtain carbon from CO2

Question 25

Free energy

Answer 25

G - energy released that is available to do work - change in energy during a reaction delta G

Question 26

Exergonic

Answer 26

negative delta G -release free energy

Question 27

Endergonic

Answer 27

positive delta G -acquire energy

Question 28

Free energy of formation

Answer 28

Gf - energy released or required during formation of a molecule from its elements A + B -> C + D delta G = Gf(C + D) - Gf(A + B)

Question 29

Activation energy

Answer 29

minimum energy required for molecules to become reactive - catalyst lowers energy

Question 30

Enzymes

Answer 30

biological catalysts typically proteins (some RNAs) active site : binds substrate

Question 31

Prosthetic groups

Answer 31

tightly bound usually bind covalently and permanently

Question 32

coenzymes

Answer 32

loosely bound most are derivative of vitamins

Question 33

chemiosmosis theory

Answer 33

all living cells use a reduction potential gradient between a primary electron donor and a terminal electron acceptor to ultimately generate energy (proton motive force) for phosphorylation reactions (ATP synthesis)

Question 34

reduction potential

Answer 34

tendency to donate electrons - more negative E' donates to more positive E'

Question 35

Oxygen (redox)

Answer 35

strongest significant natural electron acceptor

Question 36

Long-term energy storage in prokaryotes

Answer 36

glycogen, poly-beta-hydroxybutyrate, elemental sulfur

Question 37

Long-term energy storage in eukaryotes

Answer 37

starch, lipids

Question 38

Fermentation

Answer 38

anaerobic catabolism in which organic compounds donate and accept electrons

Question 39

Respiration

Answer 39

aerobic or anaerobic catabolism in which a donor is oxidized with O2 (aerobic) or other compounds (anaerobic) as an electron acceptor