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Microb 230 Unit 2 > Unit 2.1 Metabolism > Flashcards

Unit 2.1 Metabolism Flashcards

1
Q

Describe the big picture of metabolism.

A
  • Metabolism is the buildup and breakdown of nutrients within a cell
  • “The sum of all chemical reactions that take place in an organism.”
  • These chemical reactions provide energy and create substances that sustain life
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2
Q

Briefly define Catabolism

A
  • breaks down complex molecules;
  • harvests and stores energy
  • provides energy and building blocks for anabolism;
  • exergonic
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3
Q

Briefly define Anabolism

A
  • uses energy and building blocks to build complex molecules;
  • endergonic
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4
Q

Briefly define Metabolic pathways

A

are sequences of enzymatically catalyzed chemical reactions in a cell

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5
Q

Name the thing that determines a metabolic pathway.

A

The enzymes.

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6
Q

Where do the enzymes of a cell come from?

A

Enzymes are encoded by genes

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7
Q

How is energy lost during catabolism and anabolism.

A

Because they are inefficient, some energy is lost as heat.

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8
Q

Briefly describe catalyst.

A

speed up chemical reactions without being altered

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9
Q

Briefly define enzyme.

A

biological catalysts

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10
Q

Briefly describe how enzymes are a benefit to metabolism.

A

Enzymes act on a specific substrate and lower the activation energy (the energy required for a chemical reaction to occur)

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11
Q

Name two ways the environment can cause proteins to denature.

A
  • High temperature
  • extreme pH
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12
Q

Briefly describe the role of competitive inhibitors in metabolism.

A

they fill the active site of an enzyme and compete with the substrate, slowing catalysis.

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13
Q

Briefly describe the structure of a competitive inhibitor.

A

the substance is similar to the enzyme substrate (but does not react to form products).

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14
Q

When is a competitive inhibitor ineffective?

A

When concentration of the enzyme substrate is high, the substrate will out compete for the active site and catalysis will continue.

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15
Q

Briefly describe noncompetitive inhibitors.

A

interacts with another part of the enzyme (allosteric site) rather than the active site, rendering the enzyme nonfunctional

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16
Q

Name the process where a noncompetitive inhibitor reacts with an enzyme but not at its active site.

A

allosteric inhibition

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17
Q

Describe what happens during an allosteric inhibition?

A

The noncompetitive inhibitor indirectly changes the shape of the active site, rendering the enzyme nonfunctional

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18
Q

What is the effect of high substrate concentration in the presence of noncompetitive inhibitors?

A

no effect

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19
Q

Briefly describe the effect of oxidation.

A

removal of electrons

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20
Q

Briefly describe the effect of reduction.

A

gain of electrons

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21
Q

Briefly define a redox reaction.

A

an oxidation reaction paired with a reduction reaction

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22
Q

Name the word that best describe how oxidation occurs in biological systems.

A

Biological oxidations are often dehydrogenations

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23
Q

How are electrons transferred in biological systems?

A

In biological systems, electrons and protons are removed at the same time; equivalent to a hydrogen atom

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24
Q

Name the process of ATP generation from ADP.

A

ATP is generated by the phosphorylation of ADP with the input of energy.

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25
Q

Describe ATP generation with Substrate-Level Phosphorylation.

A

ATP is generated when high-energy PO4- is added to ADP

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26
Q

Where does Photophosphorylation occur?

A

only in photosynthetic cells with light-trapping pigments such as chlorophylls

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27
Q

What is the purpose of photophosphorylation?

A

Light energy is converted to chemical energy

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28
Q

Briefly describe what happens during photophosphorylation.

A

ATP is generated during the transfer of electrons (oxidation) from chlorophyll as they pass through a system of carrier molecules

29
Q

What is the role of ATP in biological metabolism?

A

To chemically store energy.

30
Q

Briefly describe the chemistry of Metabolic Pathways of Energy Production.

A
  • Series of enzymatically catalyzed chemical reactions
31
Q

Briefly describe the processes of Metabolic Pathways of Energy Production.

A
  • Extracts energy from organic compounds and stores it in chemical form (ATP)
32
Q

Briefly define chemiosmosis.

A

the process wherein ATP is generated from ADP using the energy derived from the electron transport chain.

33
Q

Briefly describe what happens during glycolysis.

A

The oxidation of glucose
to pyruvic acid
produces ATP and NADH

34
Q

Features of the preparatory stage of glycolysis.

A
  • 2 ATP are used
  • Glucose is split to form two molecules:
    one glyceraldehyde 3-phosphate (g P),
    one dihydroxyacetone phosphate (DHAP)
  • DHAP is readily converted to g P
35
Q

Features of the energy-conserving stage of glycolysis.

A
  • The two glyceraldehyde 3-phosphate molecules are oxidized to 2 pyruvic acid molecules
  • 4 ATP are produced
  • 2 NADH are produced
36
Q

Name two Additional Pathways to Glycolysis.

A

Pentose phosphate pathway
Entner-Doudoroff pathway

37
Q

Features of the Pentose phosphate pathway.

A
  • Breaks down 5-carbon pentose sugars and/or glucose and produces NADPH
  • Operates simultaneously with glycolysis
  • Can provide intermediates for synthesis reactions
38
Q

Features of the
Entner-Doudoroff pathway.

A
  • Produces NADPH and ATP
  • Does not involve glycolysis; operates independently
  • Occurs in Pseudomonas, Rhizobium, and Agrobacterium
39
Q

Features of cellular respiration.

A
  • Oxidation of molecules liberates electrons to operate an electron transport chain
  • Final electron acceptor comes from outside the cell and is inorganic
    Aerobic respiration uses oxygen as the final electron acceptor
    Anaerobic respiration uses a molecule other than oxygen as the final electron acceptor
  • ATP is generated by oxidative phosphorylation
40
Q

Features of the Kreb cycle.

A

*Aerobic Respiration
* Pyruvic acid (from glycolysis) is oxidized and decarboxylation (loss of CO2) occurs
* The resulting 2-carbon compound attaches to coenzyme A, forming acetyl CoA and NADH
* Oxidation of acetyl CoA produces NADH, FADH2 and ATP, and liberates CO2 as waste

41
Q

Features of the electron chain transport system

A
  • Aerobic Respiration
  • Occurs in the plasma membrane of prokaryotes; inner mitochondrial membrane of eukaryotes
  • Series of carrier molecules (flavoproteins, cytochromes, and ubiquinones) are oxidized and reduced as electrons are passed down the chain
  • Energy released is used to produce ATP by chemiosmosis
42
Q

Features of Chemiosmosis.

A
  • Electrons (from NADH) pass down the electron transport chain while protons are pumped across the membrane
    Establishes proton gradient (proton motive force)
  • Protons in higher concentration on one side of the membrane diffuse through ATP synthase
    Releases energy to synthesize ATP
43
Q

Features of Carbohydrate Catabolism.

A
  • Each NADH can be oxidized in the electron transport chain to produce 3 molecules of ATP
  • Each FADH2 can produce 2 molecules of ATP
44
Q

Features of Anaerobic Respiration.

A
  • The final electron acceptor in the electron transport chain is NOT O2
  • Yields less energy than aerobic respiration
45
Q

Features of Fermentation.

A
  • Releases energy from the oxidation of organic molecules
  • Glucose is oxidized to pyruvic acid, which is then reduced by N A D H
  • Does not require oxygen
  • Does not use the Krebs cycle or E T C
  • Uses an organic molecule as the final electron acceptor
  • Produces only small amounts of A T P
46
Q

Features of Lipid and Protein Catabolism.

A
  • Proteins are degraded by extracellular proteases and peptidases into amino acids
  • Amino acids cross plasma membranes
  • Deaminated, decarboxylated, desulfurized to obtain molecules that can enter the Krebs cycle for further processing
47
Q

describe Detecting Amino Acid Catabolizing Enzymes in the Lab

A

Bacteria are inoculated into tubes containing glucose, a pH indicator, and a specific amino acid.
(a) The pH indicator turns to yellow when bacteria produce acid from glucose.
(b) Alkaline products from decarboxylation turn the indicator to purple.

48
Q

Briefly describe fermentation test.

A

bacteria that catabolize carbohydrate or protein produce acid, causing the pH indicator to change color
* Can also be used with a Durham tube to detect gas production during fermentation

49
Q

What is the function of the Oxidase test.

A

identifies bacteria that have cytochrome c oxidase (e.g., Pseudomonas)

50
Q

Briefly describe the Light-dependent (light) reactions of photosynthesis.

A

conversion of light energy into chemical energy (A T P and N A D P H)

51
Q

Briefly describe the Light-independent (dark) reactions of photosynthesis.

A

A T P and N A D P H are used to reduce CO2 to sugar (carbon fixation) via the Calvin-Benson cycle

52
Q

formula of the summary reaction of photosynthesis

A

6CO2 + 12H2O + light
—>
C6H12O6 + 6H2O + O2

53
Q

Briefly define phototroph

A

organisms that use light as their energy source and carry out photosynthesis

54
Q

Briefly define Photoheterotroph

A

phototroph that uses organic compounds (carbon source)

55
Q

photoheterotrophs include what microorgansims?

A

green and purple nonsulfur bacteria

56
Q

briefly contrast cyanobacteria from other photoautotrophs

A

source of reducing power is H2O

57
Q

which photoautotrophs use sulfur?

A

green and purple sulfur bacteria

58
Q

compare similarities between cyanobacteria and algae/plants

A
  • chlorophyll a
  • thylakoids
  • reduces with H2O
  • generates O2
59
Q

contrast green and purple bacteria differences from cyanobacteria

A
  • reducing power from other compounds (not H2O)
  • does not make O2
  • found in anerobic environments
60
Q

steps of cyclic photophosphorylation

A
  • light interacts with chlorophyll in photosystem I
  • excited electrons move through the electron transport chain
  • electrons moving through cytochromes creating a proton gradient
  • proton gradient drives ATP synthase to produce ATP via chemiosmosis
  • electrons return to photosystem I
61
Q

another name for energy source in the energy production of cells

A

electron donors

62
Q

name the energy sources for the energy production of cells

A

photosynthetic pigments + light
glucose, sulfur, ammonia, hydrogen gas

63
Q

name the electron carriers in the energy production of cells

A

NADP+
NAD+
FAD

64
Q

name the final electron acceptors in the energy production of cells

A

O2 (aerobic respiration)
NO3-, SO4^2- (anerobic)
organic compound (fermentation)

65
Q

Briefly describe autotroph

A

organism that uses CO2 as carbon source

66
Q

Briefly describe heterotroph

A

organism that uses organic compounds as carbon source

67
Q

Briefly describe chemotroph

A

organisms that use chemicals as their energy source

68
Q

Features of Chemoautotrophs

A
  • Obtain energy from inorganic chemicals; use CO2 as carbon source
  • Energy is used in the Calvin-Benson cycle to fix CO2
  • Obtain energy A N D carbon from organic chemicals
  • Medically and economically important
69
Q

Briefly define Amphibolic pathways

A

metabolic pathways that function in both anabolism and catabolism

Microb 230 Unit 2 (1 decks)

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