5: Microbial Metabolism Flashcards Preview

Elementary Microbiology > 5: Microbial Metabolism > Flashcards

Flashcards in 5: Microbial Metabolism Deck (133)
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1
Q

energy in temporarily trapped in these high-energy bonds. “transient ephemeral”

A

phosphate-phosphate bond

2
Q

combine simpler substances into more complex molecules. requires energy

A

anabolic reaction

3
Q

breaks down complex organic compounds into simpler ones. releases energy

A

catabolic reaction

4
Q

ATP

A

adenosine triphosphate

5
Q

cavities (tooth decay)

A

dental caries

6
Q

what happens to the majority (60%) of energy released during catabolic processes

A

lost as heat

7
Q

Where are enzymes manufactured?

A

ribosomes > rough ER > subunits made in nucleus

8
Q

How do enzymes lower activation energies?

A

by properly aligning colliding molecules of substrate so they react more easily

9
Q

Name of the enzyme that breaks down penicillin

A

betalactimase, penicillinase

10
Q

allows some microorganisms to grow in or on the human body (i.e. dental plaque)

A

microbial metabolism

11
Q

proteins that act as catalysts in chemical reactions of importance to the cell

A

enzymes

12
Q

a substance that speeds up a reaction without being changed by it

A

catalyst

13
Q

the energy transferred by the particles in the collision can disrupt chemical bonds or form new chemical bonds

A

collision theory

14
Q

enzymes decrease the energy required to trigger the reation

A

reduce activation energy

15
Q

the “raw material” that will be transformed by the enzyme

A

substrate

16
Q

cephalosporins, carbapenems, penicillin, monobactam, etc.

A

beta-lactam antibiotics

17
Q

genes for beta-lactamases

A

R factors

18
Q

Where are the beta-lactamase R factors located in the bacteria? How are they transferred from bacteria to bacteria? Where in the body does this take place?

A

located on the plasmids, transferred by conjugation via sex pili, takes place in the large intestine

19
Q

diverse group of beta-lactamases produced by bacteria that are active against cephalosporins, carbapenems, and other antibiotics

A

carbapenemases

20
Q

NDM-1

A

New Delhi metallo-beta-lactamase

21
Q

example of carbapenemase that provides resistance to many antibiotics

A

NDM-1 (New Delhi metallo-beta-lactamase)

22
Q

protein portion of an enzyme

A

apoenzyme

23
Q

nonprotein portion of an enzyme

A

cofactor

24
Q

what can be a cofactor?

A

metal ion or coenzyme

25
Q

complex organic molecule often derived from vitamins that serve as a cofactor

A

coenzyme

26
Q

Name 3 coenzymes

A

NAD, FAD, CoA

27
Q

Full name of NAD and what vitamin it is derived from

A

nicotinamide adenine dinucleotide, derived from niacin

28
Q

Full name of FAD and what vitamin it is derived from

A

flavin adenine dinucleotide, derived from riboflavin

29
Q

Full name of CoA and what vitamin it is derived from

A

Coenzyme A, derived from panthothenic acid

30
Q

which coenzyme’s job is to transport H+ ions and electrons like a ‘taxicab’?

A

NAD

31
Q

when both the cofactor and apoenzyme are combined into their active form, name for the whole enzyme

A

holoenzyme

32
Q

acts as an anticoagulant by binding up the cofactor calcium needed for clotting enzyme activity

A

sodium citrate

33
Q

Why isn’t it dangerous to give patients blood units that contain sodium citrate?

A

living people metabolize sodium citrate, making it a reversible anticoagulant

34
Q

The substrate contacts “_____” of enzyme propelled by “______”

A

acitve site, brownian motion

35
Q

The _____ of enzyme reactions is due to the 3D shape of the active site.

A

specificity

36
Q

4 factors influencing enzyme activity

A

temperature, pH, substrate concentrations, and inhibitors

37
Q

How does temperature influence enzyme activity?

A

increased temperature causes increased brownian motion, causing increased enzyme activity and visa versa. Denaturation can occur at high temperatures.

38
Q

How does high heat cause denaturation of enzymes?

A

it breaks bonds in the protein, causing loss of 3D shape, and inability to bind with substrate

39
Q

Can you freeze human cells to preserve them?

A

yes, but not in water, because it forms ice crystals that rupture the cell membranes

40
Q

what can you freeze human cells in to preserve them?

A

glycerol, it doesn’t form ice crystals

41
Q

medical condition that results from ice crystals forming in the tissues

A

frostbite

42
Q

What happens to enzyme activity is pH rises or falls?

A

the enzymes will be denatured

43
Q

When does substrate concentration stop increasing enzymatic activity?

A

saturation of active sites (most enzymes in living cells are not saturated)

44
Q

2 categories of inhibitors

A

competitive inhibitors and noncompetitive inhibitors

45
Q

competes for active site

A

competitive inhibitor

46
Q

competitive inhibitors have what effect that may be reversible or nonreversible?

A

bacteriostatic

47
Q

don’t actively kill bacteria, just stops them from growing

A

bacteriostasis

48
Q

an antibacterial agent that inhibits the normal reaction of PABA being converted to folic acid

A

sulfanilamide

49
Q

PABA

A

para-aminobenzoic acid

50
Q

Why doesn’t sulfanilamide harm humans?

A

because human cells do not use PABA to make their folic acid, sulfanilamide inhibits bacteria but does not harm human cells

51
Q

Is the effect of sulfanilamide reversible?

A

yes, some sunscreen lotions contain PABA

52
Q

Which is the proper substrate for bacterial growth, PABA or sulfanilamide?

A

PABA

53
Q

Which is the competitive analog that prevents bacterial growth, PABA or sulfanilamide?

A

sulfanilamide

54
Q

When should bacteriostatic agents (such as sulfanilamide) NOT be used?

A

on immunocompromised patients

55
Q

pH of human blood

A

7.4 (slightly alkaline)

56
Q

may change the shape of the enzyme or may bind up an essential cofactor

A

noncompetitive inhibitors

57
Q

type of noncompetitive inhibitor that acts on the enzyme to alter shape of the active site

A

allosteric inhibition

58
Q

nerve gas

A

permanent noncompetitive allosteric enzymatic inhibition of the enzymes in the nervous system

59
Q

what type of inhibitor is sodium citrate?

A

noncompetitive inhibitor (non-allosteric)

60
Q

noncompetitive inhibitor that binds to iron in iron containing enzymes

A

cyanide

61
Q

noncompetitive inhibitor that binds to calcium or magnesium

A

fluoride

62
Q

noncompetitive inhibitor that binds to calcium

A

sodium citrate

63
Q

reversible regulatory process done in cell when the end product accumulates and then inhibits the starting enzyme through “reversible allosteric noncompetitive inhibition”. as the cell uses up the existing end product, the first enzyme’s allosteric site more often remains unbound and pathway resumes activity

A

feedback inhibition

64
Q

the addition of oxygen to a molecule or the removal of electrons from a molecule

A

oxidation

65
Q

oxidation reaction where two electrons and two hydrogen ions are removed at the same time

A

dehydrogenation

66
Q

the loss of an oxygen molecule or molecule picks up the electrons ( and H+ that typically travel with them)

A

reduction

67
Q

oxidation coupled to a reduction reaction

A

oxidation-reduction reactions

68
Q

usually an energy producing reaction

A

oxidation

69
Q

energy released during oxidation reactions is trapped in ATP by what process?

A

phosphorylation (addition of a phosphate to ADP)

70
Q

series of redox reactions that efficiently extract energy from organic compounds

A

biochemical pathway

71
Q

to produce energy from glucose, microorganisms use what two general processes?

A

cellular respiration and fermentation

72
Q

this entire process can be thought of as involving a flow of electrons from the energy-rich glucose molecule to the relatively energy-poor CO2 and H2O molecules

A

cellular respiration

73
Q

Another name for glycolysis

A

Embden-Myerhof pathway

74
Q

oxidation of glucose to pyruvic acid

A

glycolysis

75
Q

beginning reactions of both respiration and fermentation

A

glycolysis

76
Q

In glycolysis, there is a net gain of _____ for each molecule of glucose oxidized

A

2 ATP

77
Q

Glycolysis is ________ on the presence of oxygen

A

not dependant

78
Q

NAD is ______ to become NADH

A

reduced

79
Q

Pyruvic acid produced by glycolysis can undergo further degradation by what two pathways?

A

respiration or fermentation

80
Q

Where does glycolysis take place in prokaryotes? eukaryotes?

A

occurs in the cytoplasm for both

81
Q

an ATP-generating process in which chemical compounds are oxidized and the final electron acceptor is almost always an inorganic molecule (O2, SO4 2-, NO3 2-, etc)

A

respiration

82
Q

respiration where the terminal electron and hydrogen acceptor is oxygen

A

aerobic respiration

83
Q

respiration where the terminal electron and hydrogen acceptor is typically an inorganic molecule other than oxygen

A

anaerobic respiration

84
Q

“preparatory step” of aerobic respiration (other name)

A

transition reaction

85
Q

The ________ requires that the pyruvic acids be converted to _______

A

transition reaction, acetyl groups (2C)

86
Q

(in the transition reaction) the removed carbon molecules are released as carbon dioxide, a process referred to as ________

A

decarboxylation

87
Q

how many carbon dioxide molecules are released in the transition reaction?

A

2

88
Q

(in the transition reaction) ___ molecules of ______ are produced when the acetyl groups are formed. each of the acetyl groups then binds to a _______. The resulting complex is known as ________. These groups are then ready to enter the _________.

A

2 NADH, coenzyme A, acetyl coenzyme A, krebs cycle

89
Q

How many molecules of CO2 gas are generated in glycolysis?

A

NONE!

90
Q

Where does the transition reaction take place in prokaryotes? eukaryotes?

A

prokaryotes=cytoplasm, eukaryotes=mitochondrion

91
Q

series of chemical reactions in which the chemical energy in the two carbon acetyl groups is released step by step

A

krebs cycle/citric acid cycle

92
Q

As the krebs cycle proceeds the carbons in the _____ are removed and released as ______

A

2 acetyl groups, 4 CO2

93
Q

How many ATP are produced directly by the krebs cycle as the acetyl groups are processed?

A

2 ATP

94
Q

in the krebs cycle, most of the stored chemical energy released during the oxidation process is transferred via _____ to the coenzymes ____ and _____.

A

electrons and hydrogen ions, NAD, FAD

95
Q

The processing of the two acetyl groups in the krebs cycle results in the production of _____ and _____

A

6 NADH and 2 FADH2

96
Q

Where does the krebs cycle take place in prokaryotes? eukaryotes?

A

prokaryotes=inner surface of the plasma membrane and in the cytoplasm. eukaryotes=mitochondra

97
Q

consists of a sequence of carrier molecules (cytochromes) that pass electrons from one to another, creating a stepwise release of energy, and ATP is generated

A

electron transport chain

98
Q

one NADH processed by the electron transport chain will cause the production of ______

A

3 ATP

99
Q

one FADH2, which enters the electron transport chain one step lower than NADH, will cause the production of _____

A

2 ATP

100
Q

aerobic respiration results in _____ being indirectly produced in the electron transport chain

A

34 ATP

101
Q

aerobic respiration produces a net gain of ______ for the prokaryotic cell

A

38 ATP

102
Q

aerobic respiration produces a net gain of _____ for the eukaryotic cell

A

36 ATP

103
Q

Where is sodium citrate metabolized?

A

krebs cycle, citric acid cycle

104
Q

iron containing enzymes (iron cofactor)

A

cytochrome

105
Q

Why do microbes get more energy from aerobic respiration than eukaryotic cells?

A

microbes dont have mitochondria, so they don’t have to use 2 ATP for the mitochondria to transport electrons

106
Q

In aerobic respiration, the terminal electron acceptor is oxygen, which is converted to water. This results in the production of what?

A

300-500ml of metabolic water daily

107
Q

Where does the electron transport chain take place in prokaryotes? eukaryotes?

A

plasma membrane, mitochondria

108
Q

What type of enzyme inhibition does cyanide use?

A

irreversible noncompetitive inhibition

109
Q

Cyanide works by binding up _____, an essential cofactor needed by ________.

A

iron, cytochrome enzyme

110
Q

Why does cyanide kill you instantly?

A

lose all ATP except from glycolysis, can’t support brain and heart energy need, lack of high energy phosphate bonds

111
Q

what is capable of anaerobic respiration

A

a few bacteria

112
Q

which typically has a higher yield of ATP, anaerobic or aerobic respiration?

A

aerobic respiration

113
Q

which organisms typically grow slower, anaerobic or aerobic? why?

A

anaerobic, due to lower yield of ATP in respiration

114
Q

continuation of glycolysis which by passes the krebs cycle and the electron transport chain

A

fermentation

115
Q

provides a way for the NADH generated in glycolysis to be recycled to NAD without the use of electron transport chain (respiration)

A

fermentation

116
Q

2 types of fermentation

A

lactic acid fermentation and alcoholic fermentation

117
Q

In lactic acid fermentation, what acts as the final electron acceptor from NADH?

A

pyruvic acid (an organic molecule)

118
Q

In lactic acid fermentation, after pyruvic acid receives the H ions and electrons, the _____ is regenerated and the pyruvic acid is transformed into _____.

A

NAD, lactic acid

119
Q

In alcoholic fermentation, pyruvic acid first has ___ molecule of _____ removed and released as ____

A

one CO2 gas

120
Q

two carbon acetyl group

A

acetaldehyde

121
Q

In alcoholic fermentation, what acts as the terminal electron acceptor from NADH?

A

acetaldehyde (two carbon acetyl group)

122
Q

In alcoholic fermentation, after acetaldehyde receives the H ions and electrons, the _____ is regenerated and the acetyl group is transformed into _____.

A

NAD, ethanol

123
Q

baker’s yeast, brewer’s yeast

A

saccharomyces cerevisiae

124
Q

How many ATP are produced in fermentation?

A

none, only 2ATP produced in the initial reactions of glycolysis are gained

125
Q

Aerobic respiration directly produces ____ATP, indirctly produces ___ ATP in prokaryotes, and _____ ATP in eukaryotes

A

4, 34, 32

126
Q

skeletal muscles can still survive on this for about 2 hours after the heart and brain are dead. also how we can still contract muscles even with reduced O2

A

lactic acid fermentation

127
Q

reversible once O2 is available.

A

lactic acid fermentation

128
Q

How do you break down lactic acid once O2 is available?

A

by breathing hard. once your breathing is slowed, the lactic acid is gone

129
Q

Why is alcohol carbonated?

A

release of CO2 gas from pyruvic acid

130
Q

What makes bread rise?

A

CO2 gas released from the breakdown of pyruvic acid to acetaldehyde during alcohol fermentation. The alcohol evaporates out of the dough as the bread is baked

131
Q

Why do you die from suffocation?

A

lack of terminal electron and hydrogen acceptor, lack of high energy phosphate bonds

132
Q

How many ATP are lost due to suffocation?

A

32 from electron transport chain and 2 from transition step = 34 ATP total

133
Q

Why does suffocation take longer than cyanide to kill you?

A

you can still use residual O2 as final electron and H acceptor. cyanide inhibits cytochrome instatly, regardless of how much O2 is available