Module 4

Question 1

Activation energy

Answer 1

the minimum amount of energy that must be provided to compounds to result in a chemical reaction.

Question 2

Aerobic respiration

Answer 2

a metabolic catabolic process that captures electrons from a food substrate and captures energy for the cell via passing electrons down an electron transport chain to oxygen as the terminal electron acceptor.

Question 3

Allosteric regulation

Answer 3

regulation of an enzyme by reversible noncovalent binding of an effector at a regulatory site that is distinct from the enzyme’s active site.

Question 4

Anabolism

Answer 4

that part of metabolism dealing with the use of energy in biosynthesis, i.e., the joining together of monomer ‘building block’ units to generate the macromolecules of the cell.

Question 5

Anaerobic respiration

Answer 5

a metabolic catabolic process that captures electrons from a food substrate and captures energy for the cell via passing electrons down an electron transport chain to a terminal electron acceptor other than oxygen.

Question 6

ATP Synthase

Answer 6

a transmembrane multi-protein motor that catalyses synthesis of ATP from ADP and organic phosphate by capturing energy released by gated transport of H+ ions into the cell across the cytoplasmic membrane.

Question 7

ATP

Answer 7

Adenosine triphosphate, the major energy currency within cells.

Question 8

Autotroph

Answer 8

organism that can fix carbon from CO2.

Question 9

Biochemical pathway

Answer 9

a series of chemical reactions carried out by proteins encoded by an organism to generate cellular metabolites, and/or to capture energy.

Question 10

Biosynthesis

Answer 10

a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms.

Question 11

Calvin-Benson cycle

Answer 11

anabolic pathway used by many organisms to fix CO2.

Question 12

Catabolism

Answer 12

that part of metabolism dealing with breaking down substrate/food molecules for energy and production of ‘building blocks’.

Question 13

Catalyst

Answer 13

in chemistry, any substance that increases the rate of a reaction without itself being consumed.

Question 14

Chemolithotroph

Answer 14

bacteria and archaea that capture energy by oxidation of inorganic molecules and use the reducing power for oxidative phosphorylation and for anabolic pathways.

Question 15

chemoorganotrophs

Answer 15

organisms which use the chemical bonds in organic compounds or O2 as their energy source and obtain electrons or hydrogen from the organic compounds, including sugars (i.e., glucose), fats and proteins.

Question 16

Chemotroph

Answer 16

organism that obtains energy from oxidation of organic or inorganic compounds.

Question 17

Coenzyme

Answer 17

An organic non-protein compound that binds with an enzyme to catalyze a reaction.

Question 18

Covalent modification of enzymes

Answer 18

altered activity of an enzyme/protein as a result of addition of a small group to a specific site on the protein.

Question 19

Electron acceptor

Answer 19

in a redox reaction, the partner that receives an electron from the electron donor (i.e., it is reduced).

Question 20

Electron donor

Answer 20

in a redox reaction, the partner that donates an electron to the electron acceptor (i.e., it is oxidized).

Question 21

Electron transport chain (ECT)

Answer 21

a system of membrane embedded electron carriers that are ordered in a redox gradient in such a fashion as to pump H+ ions outside the membrane as electrons flow down the chain to the terminal electron acceptor.

Question 22

Embden-Meyerhof pathway

Answer 22

a common metabolic pathway for degrading glucose to pyruvate.

Question 23

Energy capture

Answer 23

the process by which energy is derived from external sources.

Question 24

Entner-Doudoroff Pathway

Answer 24

a pathway for degrading glucose to pyruvate common in some Gram-negative bacteria.

Question 25

Enzymes

Answer 25

proteins with catalytic activity.

Question 26

Feedback inhibition

Answer 26

a process whereby the end product metabolite of a metabolic pathway binds allosterically to a regulatory enzyme in the pathway (usually the first dedicated step) to inhibit it.

Question 27

Fermentation

Answer 27

a catabolic metabolic process that captures energy for the cell utilizing substrate level phosphorylation and electrons removed from the ‘food source’ are passed to an endogenous (within the cell) electron acceptor, often the end metabolite of the fermentation pathway.

Question 28

ΔG

Answer 28

The change in Gibbs free energy. positive ΔG indicates a requirement for added energy (for a chemical reaction).

Question 29

Negative ΔG

Answer 29

indicates a release of energy (for a chemical reaction)

Question 30

positive ΔG

Answer 30

indicates a requirement for added energy (for a chemical reaction)

Question 31

Gluconeogenesis

Answer 31

an anabolic pathway to generate glucose from pyruvate, basically runs glycolysis in reverse direction (with some novel enzymes).

Question 32

Heterotroph

Answer 32

obtains carbon from organic molecules.

Question 33

High-energy bonds

Answer 33

A chemical bond whose hydrolysis results in the generation of energy that, if coupled to an energetically unfavourable reaction, it can drive that reaction forward.

Question 34

First law of thermodynamics

Answer 34

Law of Conservation of Energy, states that energy cannot be created or destroyed in an isolated system

Question 35

Second law of thermodynamics

Answer 35

the entropy (measure of randomness or disorder of a system) of any isolated system always increases

Question 36

Third law of thermodynamics

Answer 36

the entropy of a system approaches a constant value as the temperature approaches absolute zero

Question 37

Lithotroph

Answer 37

organism that can obtain energy from inorganic molecules.

Question 38

Macromolecule

Answer 38

complex molecules created via joining of simple structural units (monomers) together by repeating covalent bonds.

Question 39

Metabolism

Answer 39

The chemical reactions related to harvesting, capturing, storing, and using energy for maintaining the state of a living cell.

Question 40

Nicotinamide adenine dinucleotide (NAD+)

Answer 40

cellular enzyme cofactor that acts as an electron acceptor (or donor in its NADH + H+ form) and carries electrons within the cell between NAD-dependent enzymes.

Question 41

Organotroph

Answer 41

chemotrophic organism that obtains energy from reduced organic compounds.

Question 42

Redox Reactions

Answer 42

reactions in which electrons move from an electron donor to an electron acceptor.

Question 43

Oxidation

Answer 43

The loss of electrons during a reaction.

Question 44

Oxidative phosphorylation

Answer 44

The process by which ATP is synthesized using the energy from electron transport (via ATP synthase), which is driven by the oxidation of a chemical energy source.

Question 45

Pentose phosphate pathway

Answer 45

a common metabolic pathway involving five carbon sugars and generating NADPH reducing power for biosynthetic reactions

Question 46

Photosynthesis

Answer 46

process of both obtaining energy and reducing CO2 from energy and reducing power from light capture.

Question 47

Phototroph

Answer 47

organism that obtains energy from light.

Question 48

Post-translational regulation

Answer 48

regulation of enzyme activity or stability after completion of its translation into a mature enzyme

Question 49

Precursor metabolites

Answer 49

intermediates of catabolic pathways that serve as the raw material for creation of monomer building blocks in anabolic pathways

Question 50

Proton motive force

Answer 50

the combined chemical and electrical potential differences generated across the membrane generated by H+ transport coupled to electron transport.

Question 51

Purines

Answer 51

heterocyclic, nitrogen-containing molecule with two joined rings that occurs in nucleic acids and other cell constituents, including adenine and guanine.

Question 52

Pyrimidines

Answer 52

nitrogen-containing molecule with one ring that occurs in nucleic acids and other cell constituents; the most important being cytosine, thymine, and uracil.

Question 53

Redox tower

Answer 53

a diagram with common redox participants in order from strong negative redox potential to strong positive redox potential.

Question 54

Reduction

Answer 54

The gain of electrons during a reaction.

Question 55

Respiration

Answer 55

a metabolic catabolic process that captures electrons from a food substrate and captures energy for the cell via passing electrons down an electron transport chain.

Question 56

Standard reduction potential (E0)

Answer 56

A measure of the tendency of the donor of a half reaction to lose electrons at pH 7.

Question 57

Substrate

Answer 57

a molecule acted upon by an enzyme.

Question 58

Terminal electron acceptor

Answer 58

final recipient of electrons as they flow down an electron transport chain, for human and many bacteria, O2 serves as the final acceptor.

Question 59

Transcriptional regulation

Answer 59

regulation of protein synthesis during transcription of mRNA, a primary control mechanism that effectively ‘turns on’ or ‘turns off’ the expression of a gene or sets of genes.

Question 60

Translational regulation

Answer 60

regulation of protein synthesis through how efficiently the mRNA message is translated into a protein.

Question 61

Tricarboxylic acid cycle (TCA cycle)

Answer 61

a common cyclic catabolic pathway that accepts two carbons from acetyl-CoA and proceeds through multiple steps to generate reducing power while realizing two carbons as CO2.

Question 62

Krebs cycle

Answer 62

a common cyclic catabolic pathway that accepts two carbons from acetyl-CoA and proceeds through multiple steps to generate reducing power while realizing two carbons as CO2.

Question 63

Citric acid cycle

Answer 63

a common cyclic catabolic pathway that accepts two carbons from acetyl-CoA and proceeds through multiple steps to generate reducing power while realizing two carbons as CO2.