Metabolism I

Question 1

Metabolism

Answer 1

All chemical reactions in a cell

Question 2

Catabolism

Answer 2

Breakdown of complex molecules into smaller ones, releasing energy

Question 3

Anabolism

Answer 3

Reactions that build cells

Question 4

Energy from anabolism comes from what?

Answer 4

Catabolism

Question 5

What is the energy currency of cells?

Answer 5

ATP

Question 6

3 parts of adenosine triphosphate (ATP)

Answer 6

Adenine (base)
Ribose (sugar)
3 phosphate groups

Question 7

Adenosine

Answer 7

Adenine plus ribose

Question 8

What do the phosphate groups of ATP serve as?

Answer 8

Energy storage

Question 9

Phosphate group removal from ATP results in what?

Answer 9

Large negative standard free energy change (delta G)

Question 10

4 energy-generating reactions for cells

Answer 10

Aerobic respiration
Anaerobic respiration
Fermentation
Photosynthesis

Question 11

From where is ATP generated for aerobic and anaerobic respiration?

Answer 11

Oxidative phosphorylation

Question 12

From where is ATP generated for fermentation?

Answer 12

Substrate-level phosphorylation

Question 13

From where is ATP generated for photosynthesis?

Answer 13

Photophosphorylation

Question 14

Enzyme definition

Answer 14

Proteins (usually) that catalyze reactions

Question 15

Exception to enzymes being proteins

Answer 15

Ribozymes are catalytic RNAs

Question 16

Activation energy

Answer 16

Energy required to bring reacting molecules together

Question 17

How do enzymes increase reaction rates?

Answer 17

Lower activation energy

Question 18

Phosphatase

Answer 18

Enzyme that removes phosphate

Question 19

Kinase

Answer 19

Enzyme that attaches phosphate

Question 20

Cellulase

Answer 20

Enzyme that acts on cellulose

Question 21

How do enzymes lower activation energy?

Answer 21

Increase local concentrations of substrates

Orient substrates properly for reactions to proceed

Question 22

Oxidation in redox reactions

Answer 22

Removal of electrons

Question 23

Reduction in redox reactions

Answer 23

Addition of electrons

Question 24

“OIL RIG” in redox reactions

Answer 24

Oxidation Is Loss

Reduction Is Gain

Question 25

Substance ____ is donor, substance ____ is acceptor

Answer 25

Oxidized | Reduced

Question 26

Oxidation-reduction reactions often involve not just the transfer of electrons but both an _____.

Answer 26

Electron + proton

Question 27

Redox couple

Answer 27

Oxidation-reduction pair | Acceptor + donor

Question 28

Reduction potential (E0): what is it and what does it measure?

Answer 28

Equilibrium constant for redox reaction | Measures tendency of donors to lose electrons

Question 29

More negative E0, better ____ | More positive E0, better ____

Answer 29

More negative E0: better donor | More positive E0: better acceptor

Question 30

Half reaction formula

Answer 30

Acceptor + number of electrons -> donor

Question 31

Couples with more ___ E0 will donate electrons to couples with more ___ E0

Answer 31

More negative E0 donate to couples with more positive E0

Question 32

Electron tower

Answer 32

Displays redox pairs according to E0: more negative at top (better electron donors), more positive at bottom (better electron acceptors)

Question 33

Great electron acceptor

Answer 33

Oxygen

Question 34

Great electron donor

Answer 34

Hydrogen

Question 35

The greater the difference between two redox pairs in the electron tower, the more negative the ___ and the greater ___ can be released

Answer 35

More negative the delta G value | Greater energy can be released

Question 36

Freely diffusible electron carrier: what can it do, what are examples

Answer 36

Can diffuse around cytoplasm of cell | Examples: NAD+ and NADP+

Question 37

"Reducing power" of the cell: what two molecules?

Answer 37

NADH and NADPH

Question 38

Membrane bound electron carrier: examples

Answer 38

Flavoproteins Cytochromes Quinones

Question 39

Microbes transfer energy by moving electrons from what to what to what to what?

Answer 39

Reduced food molecules (glucose) -> diffusible carriers in cytoplasm -> membrane-bound carriers -> O2, metals, or oxidized forms of N and S

Question 40

2 classifications of carbon metabolizers

Answer 40

Heterotrophs | Autotrophs

Question 41

Heterotrophs: what is carbon source, what is yielded, what types of organisms

Answer 41

Reduced, preformed organic compounds as carbon source Convert large amounts of carbon to CO2 Animals and microbes

Question 42

Autotrophs: what is carbon source, what is yielded, what types of organisms

Answer 42

CO2 as carbon source Synthesize organic compounds used by heterotrophs Plants and microbes

Question 43

Autotrophs are also called what?

Answer 43

Primary producers

Question 44

2 classifications of energy users

Answer 44

Phototrophs | Chemotrophs

Question 45

Phototrophs: energy source

Answer 45

Light

Question 46

Chemotrophs: energy source

Answer 46

Oxidation of chemical compounds (often same as their carbon source)

Question 47

2 classifications of electron users

Answer 47

Lithotrophs | Organotrophs

Question 48

Lithotrophs: electron source, what types of organisms

Answer 48

Use inorganic molecules as electron donors | Unique to a few bacteria and archaea

Question 49

Organotrophs: electron source

Answer 49

Organic molecules as donors

Question 50

Organotrophs: many different energy sources are funneled into common _____ pathways

Answer 50

Degradative

Question 51

Organotrophs: most pathways generate ___ or intermediates of the pathways used in ___ metabolism

Answer 51

Glucose, glucose

Question 52

Two functions of organic energy sources

Answer 52

Oxidized to release energy | Provide building blocks for anabolism

Question 53

Amphibolic pathway

Answer 53

Metabolic pathway that functions both catabolically and anabolically

Question 54

Aerobic respiration

Answer 54

Process that completely catabolizes an organic energy source to CO2

Question 55

Aerobic respiration uses these 4 methods for catabolism

Answer 55

Glycolytic pathways (glycolysis) Tricarboxylic acid cycle Electron transport chain with oxygen as final electron acceptor Production of ATP (most indirectly, via electron transport chain)

Question 56

Breakdown of glucose to pyruvate: 3 pathways

Answer 56

Embden-Meyerhof (glycolysis) Pentose phosphate Entner-Doudoroff

Question 57

Embden-Meyerhof (glycolysis): how commonly is it used for glucose breakdown, where does it occur, does it need oxygen, how many reactions in how many stages?

Answer 57

Most common form of glucose breakdown Occurs in cytoplasm Functions in presence or absence of oxygen Ten reactions in 2 stages

Question 58

2 stages of glycolysis

Answer 58

6 carbon stage and 3 carbon stage

Question 59

6 carbon stage: reactions, is ATP generated or used

Answer 59

Glucose is phosphorylated twice to yield fructose 1,6-bisphosphate ATP is used

Question 60

3 carbon stage: reactions, is ATP generated or used

Answer 60

Fructose 1,6-bisphosphate is split into 2 glyceraldehyde-3-phosphates then converted to pyruvate ATP is generated

Question 61

What two molecules are generated from the 3 carbon stage of glycolysis and what type of reactions generate them?

Answer 61

NADH (oxidation) | ATP (substrate level phosphorylation)

Question 62

Net yield of glycolysis

Answer 62

2 ATP, 2 NADH, 2 pyruvate

Question 63

Is glycolysis a catabolic, anabolic, or amphibolic pathway?

Answer 63

Amphibolic

Question 64

Precursor metabolites yielded from glycolysis

Answer 64

Starting molecules for biosynthesis (glucose 6-phosphate, fructose 6-phosphate)

Question 65

What does fructose-6 phosphate yield that is important for bacterial cell walls?

Answer 65

N-acetylglucosamine and N-acetylmuramic acid: sugars used in peptidoglycan

Question 66

3 NADH and ATP generating steps in glycolysis

Answer 66

1. Glyceraldehyde-3-phosphate is oxidized and phosphorylated to generate a high-energy phosphate bond; NAD+ is reduced to NADH; 1,3-bisphosphoglycerate is formed 2. Substrate level phosphorylation of ADP by high energy metabolic substrate; 1,3-bisphosphoglycerate to 3-phosphoglycerate 3. Substrate level phosphorylation produces ATP; phosphoenolpyruvate to pyruvate

Question 67

Enzyme that reduces NAD+ to NADH in glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate step in 3 carbon stage of glycolysis

Answer 67

G3P dehydrogenase

Question 68

Enzyme that produces 3-phosphoglycerate from 1,3-bisphosphoglycerate in 3 carbon stage of glycolysis

Answer 68

3PG kinase

Question 69

Enzyme that catalyzes phosphoenolpyruvate to pyruvate

Answer 69

Pyruvate kinase