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Microbiology LECTURE > Ch 5 Microbial Metabolism > Flashcards

Ch 5 Microbial Metabolism Flashcards

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1
Q

Conjugated proteins

A

Enzyme components that include apoenzyme and cofactor/coenzyme

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2
Q

What is fermentation

A

Any metabolic process that releases energy from a sugar other organic molecule. It does not require oxygen or an Elektron transport system and uses an organic molecule as a final electron acceptor.

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3
Q

Catabolism

A

The breakdown of complex organic compounds into simpler ones

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4
Q

Metabolism

A

Refers to the sum of all chemical reactions within a living organism. Includes 2 classes: release of energy and requiring energy

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5
Q

Catabolism in living cells is an enzyme regulated chemical reaction that _____________ energy

A

Releases

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6
Q

What are 3 characteristics of catabolic reactions

A
  1. Enzyme regulated chemical reaction that releases energy
  2. Generally hydrolytic reactions: use water to break chemical bonds
  3. Exergonic: produce more energy than they consume
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7
Q

Example of catabolic reaction

A

Cells break down sugars into CO2 and H20

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8
Q

Anabolism

A

The building of complex organic molecules from simpler ones

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9
Q

Characteristics of an anabolic reaction

A
  1. Enzyme regulated energy requiring reaction
  2. Involved in dehydration synthesis reaction: reactions that release water
  3. Endergonic–> consume more energy than they produce
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10
Q

Another word for catabolic reaction

A

Degradative reaction

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11
Q

Another word for anabolic reaction

A

Biosynthetic reaction

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12
Q

Example of anabolic reaction

A

Formation of:

  1. protein from aa,
  2. nucleic acid from nucleotides,
  3. polysaccharides from simple sugars
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13
Q

How do catabolic reactions help anabolic reactions

A

They provide the building blocks for anabolic reactions. They furnish the energy needed to drive anabolic reactions–>ATP.

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14
Q

What is ATP

A

Stored energy derived from catabolic reactions. They use it later to drive anabolic reactions and perform other cellular work

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15
Q

When is ADP formed

A

Formed when terminal phosphate group split from ATP and energy is released to drive anabolic reactions.

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16
Q

Metabolic pathway

A

A sequence of chemical reactions

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17
Q

What determines a metabolic pathway

A

Its enzymes which are determined by the cells genetic make up

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18
Q

Collision theory

A

The principle that chemical reactions occur because energy is gained as particles collide (atoms, ions, molecules)

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19
Q

What effect does the energy transfer of colliding particles have on electron structure and chemical bonds

A

It can disrupt electron structure enough to break chemical bonds and build new bonds

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20
Q

What factors determine if a chemical reaction will occur

A
  1. Velocity of colliding particles
  2. Their energy
  3. Specific chemical configurations
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21
Q

How does velocity of particles effect chemical reaction

A

The higher the velocity the higher the probability of reaction

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22
Q

How does energy effect a chemical reaction

A

Each chemical reaction requires a specific level of energy

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23
Q

How does configuration affect a chemical reaction

A

Particles need to be properly oriented toward each other to react

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24
Q

What is activation energy

A

The collision required for a chemical reaction to take place. The amount of energy needed to disrupt the stable electronic configuration of any specific molecule so the electrons can be rearranged.

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25
Q

What is reaction rate

A

The speed at which a reactant is converted to a product.

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26
Q

What is reaction rate dependent on

A

The frequency of collisions containing sufficient energy to bring about a reaction depend on the number of reactant molecules at or above the activation energy level

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27
Q

What things increase a reaction rate

A

Temperature, pressure, enzymes

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28
Q

In living things, why are enzymes a crucial function

A

They can speed up biochemical reactions at temperatures compatible with normal functioning of cell. Their reactions are also reversible.

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29
Q

Catobolites

A

Catabolism intermediates

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30
Q

What is a catalyst

A

Substance that can speed up a chemical reaction without being altered themselves

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31
Q

Biological catalyst

A

Specific for a chemical reaction not used up in that reaction

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32
Q

In a living substance, enzymes serve as

A

Biological catalysts that act on specific substance(s)/enzymes substance

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33
Q

Example of biological catalyst of sucrose and teleological reasoning

A
  • Sucrase is an enzyme and biological catalyst. •Sucrose is a substrate of sucrase.
  • Sucrase catalyzes the hydrolysis of sucrose.
  • The end products are glucose and fructose
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34
Q

Active site

A

Region that interacts with specific substance

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35
Q

How do enzyme accelerate chemical reactions

A

The 3D molecule has an active site, it orients substrate into position that increases probability of reaction

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36
Q

Enzyme substrate complex

A

Temporary binding of enzyme and reactants that enables collisions to be more effective and lowers activation energy of reaction

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37
Q

What allows for enzyme specificity

A

Made possible by structure and 3D shape with specific surface configurations

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38
Q

What makes enzyme efficient

A

At optimal conditions they
1. catalyze at rates of 10^8-10^10 times or higher 2. can have a turnover of 1-10,000 or as high as 500,000 per sec ok nd

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39
Q

What is meant by enzyme turnover number

A

The max substrate to product an enzyme converts per second

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40
Q

Are enzymes in cell always active

A

No, can be inactive. Its determined by cellular environment.

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41
Q

What are the 6 classes of enzymes

A
  1. Oxidoreductase
  2. Transferase
  3. Hydrolase
  4. Lyase
  5. Isomerase
  6. Ligase
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42
Q

Oxidoreductase

A

Oxidation-reduction in which oxygen and hydrogen are gained or lost

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43
Q

Tranferase

A

Transfer of functional groups such as amini group, acetyl group, phosphate group

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44
Q

Hydrolase

A

Hydrolysis–>addition of water

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45
Q

Lyase

A

Removal of groups of atoms without hydrolysis

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46
Q

Isomerase

A

Rearrangement of atoms within a molecule

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47
Q

Ligase

A

Joining of 2 molecules, using energy usually derived from the breakdown of ATP

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48
Q

What is an enzyme made of

A

Some made mostly of proteins and others made up of a portion of protein and a non protein component

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49
Q

Apoenzyme

A

Protein portion if the enzyme and is inactive without cofactor/conenzyme

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50
Q

Cofactor

A

Non protein component of the enzyme made up of ions of a specific metal ion such as iron, zinc, magnesium, or calcium

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51
Q

Conenzyme

A

Is a non protein component of the enzyme made up of an organic molecule

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52
Q

Holoenzyme

A

Apoenzyme+cofactor. It is an active enzyme. If the cofactor is removed it will not function.

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53
Q

How do coenzymes assist enzymes

A

Coenzymes act as electron carriers:

  1. Accept atoms removed from substrate
  2. Donate atoms required by substrate.
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54
Q

Where do coenzymes come from

A 
Derived from vitamins:
Vit B 1,2,6,12
Niacin 
Pantothenic acid
Biotin
Folic acid
Vit E and K
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55
Q

2 most important coenzymes

A
  1. NAD+ : nicotinamide adenine dinucleotide

2. NADP+: nicotinadine adenine dinucleotide phosphate

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56
Q

NAD and NADP both (3)

A

Derived from B vitamin
Function as electron carriers
Important in cellular metabolism

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57
Q

What kind of reactions are NAD mostly involved in

A

Catabolic reactions

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58
Q

NADP are primarily involved in __________ reactions

A

Anabolic

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59
Q

Common coenzymes

A

Flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD), CoA (coenzyme A)

60
Q

What major role does FAD in Cellular respiration

A

Act as electron carriers

61
Q

What role does CoA play

A

In the synthesis and breakdown of fats and Krebs cycle

62
Q

What do cofactor consist of

A

They are metal ions like iron, copper, magnesium, zinc,calcium, and cobalt

63
Q

How do cofactors help catalyze a reaction

A

By forming a bridge between enzyme and substrate

64
Q

What is an allosteric site

A

AKA regulatory site. A different site of attachment for non-competitive inhibitor. Substrate cannot attach here.

65
Q

What is the mechanism of enzymatic action

A
  1. Substate comes in contact with active site
  2. Forms enzyme substrate complex
  3. Substrate molecule is transformed
  4. Produts of reaction are released from enzyme
  5. Unchanged enzyme is free to react with other substrates
66
Q

What factors influence enzyme activity

A

Temperature
pH
Substrate concentration
Inhibitors

67
Q

Mechaniism of enzymatic action is based on…

A

Collision theory; proximity and orientation

68
Q

Endoenzyme

A

Active inside cell

69
Q

Exoenzyme

A

Active outside cell; secreted out

70
Q

Constitutive enzyme

A

Expressed at constant levels in cell at all times

71
Q

Inducible enzymes

A

Made/expressed only when needed

72
Q

Example of gram negative exoenzyme

A

Lipid A layer of phospholipid outer cell layer has a toxin that can be released into the surrounding environment if activated

73
Q

Enzymes lower___________ ___________of chemical reaction

A

Activation energy

74
Q

How is substrate molecule transformed into products

A

After enzyme-substrate complex is formed the following can occur:

  1. Rearrangement of existing atoms
  2. Breakdown of substrate molecule or combination with another substrate molecule
75
Q

What things allow for an enzyme to have specificity of a particular substrate

A
  1. 3d shape of active site is like a lick and key fit
  2. Active site and substrat and substrate flexible
  3. Substrate smaller than enzyme
  4. Few aa make up active site
76
Q

What are the 2 primary cellular controls in enzymatic activity

A
  1. Enzyme synthesis –>how much

2. Enzyme activity –> how active

77
Q

How does temperature influence enzyme activity

A

Rate of most chemical reactions increase as temperature increases. At lower temperatures molecules move slower and may not have enough energy to cause chemical reaction

78
Q

What is the optimal temperature for disease producing bacteria in human body

A

35°C to 40°C

79
Q

What happens to enzymes above 40°C

A

Enzymes denature: loss of 3D structure and breaking hydrogen bonds and non covalent bonds, also changes arrangement of aa on active site and loses ability to catalyze.

80
Q

What can cause denaturing of enzymes

A

Concentrated acids, based, heavy metal ions (lead, arsenic, mercury), alcohol, uv radiation

81
Q

What happens to enzymes at ir below optimal range

A

Reactions decrease, can cause alteration of struct6and denaturing of proteins

82
Q

What happens to chemical reactions at substrate concentrations above max rate

A

This happens when all the active sites on enzyme are saturated. Increasing substrate above this has no farther effect

83
Q

What happens to enzyme when there is a lack of substrate

A

Become inactive

84
Q

What are enzyme inhibitors used for

A

Control growth of bacteria by controlling their enzymes .

85
Q

What are enzyme inhibitors

A

They are analogous to substrate and compete for activation site of enzyme or bind at allosteric site. When they combine with enzyme they either decease reaction rate or prevent their normal function. This can cause the cell to stop working and can cause cell death.

86
Q

Examples of enzyme inhibitors

A

Poisons–> cyanide, arsenic, mercury

Antibiotics–> Sulfa. Ampicillin

87
Q

What are the 2 classes of enzyme inhibitors

A
  1. Competitive inhibitors

2. Non competitive inhibitors

88
Q

Competitive inhibitors

A
  1. Compete for and Fill the active site of enzyme
  2. Does not undergo reaction
  3. Some bind irreversibly to aa at active site
  4. Others bind reversibly: occupy and leave
  5. Certain chemicals can bind or tie up metal ion activators and prevent enzymatic reaction
89
Q

What happens to active site once allosteric site is occupied

A

It becomes altered, enzyme changes shape, active site changes, and it becomes inactive for substrate

90
Q

How does Sulfa inhibit bacterial enzyme

A

It selectively toxic on bacteria. It attaches to active site and prevents substrate PABA from binding with enzyme. PABA is required for folic acid synthesis. Without this bacteria cannot grown and will dies.

91
Q

Non competitive inhibitors

A
  1. Do not compete with substrate for active site
  2. interact with allosteric site
  3. Active site becomes non functional
  4. Enzyme activity decreases
  5. Can be reversible or irreversible
  6. Can sometimes activate enzyme instead of inhibiting
92
Q

What is end product inhibition

A

It is a biochemical control. Also know as feedback inhibition. It stops a cell from making more of a substance than it needs/ prevents wasting of chemicals

93
Q

What is the allosteric inhibitors role

A

The final product of anabolic pathway is used to inhibit the activity of one of the enzymes earlier in the metabolic pathway, usually the first enzyme. The prevents the fist enzymatic reaction and the entire pathway is shut down.

94
Q

How long does feedback inhibition last

A

It is maintained until supply is depleted.

95
Q

What are ribozymes

A

A unique type of RNA. Just like protein enzymes they function as catalysts , have active sites, and are not used up in chemical reaction

96
Q

What restrictions do ribozymes have

A

Their interaction with substrates are restricted. They act specifically on strands of RNA by removing sections and splicing together remaining pieces

97
Q

How is energy produced

A

Nutrient molecules have energy associated with electrons that form bonds between atoms. Catabolic pathways concentrate energy into bonds of ATP, making them readily available for anabolic reactions

98
Q

How are ATPs high energy bonds useful for anabolic reactions

A

They are unstable and can be easily released for quick and easy use in anabolic reactions, and they are not large molecules.

99
Q

Oxidation-reduction

A

The removal of electrons from an atom or molecule coupled with simultaneous gain of one or more electrons of another atom or molecule

100
Q

In biological systems, electrons are often associated with ________ _________.

A

Hydrogen atoms

101
Q

Biological oxidation are often

A

Dehydrogenations

102
Q

Hydrogenation is made up of

A

1 electron and 1 proton

103
Q

Dehydrogenation reaction

A

Loss of hydrogen atoms

104
Q

Which has more energy NADH or NAD+

A

NADH. It has energy that can be used to generate ATP in later reaction

105
Q

How is ATP generated

A

By phosphorylation of ADP

106
Q

Cells use biological redox reactions in catabolism to

A

Extract energy from nutrient molecules. These energy sources are degrade from highly reduced compounds to highly oxidized compounds

107
Q

What type of compounds are highly reducible

A

Compounds that have many hydrogen atoms like glucose

108
Q

Where is energy trapped after it is released from redox reaction

A

Within cell by formation of ATP

109
Q

What is phosphorylation

A

The addition of a phosphate to a chemical compound

110
Q

What is substrate level phosphorylation

A

The generation of ATP from the direct transfer of a high energy phosphate from a phosphorylated compound to ADP

111
Q

Oxidative Phosphorylation

A

Electrons are transferred from organic compounds to one group of electron carriers, usually NAD and FAD

112
Q

What happens after oxidation phosphorylation takes place

A

Electrons are passed through a series of different electron carriers to molecules to molecules of 02 or other oxidized inorganic or organic molecules

113
Q

Where does oxidative phosphorylation take place

A

In plasma of prokaryotes or inner mitochondrial membrane of eukaryotes

114
Q

What is the sequence of electron carriers called that takes place during oxidative phosphorylation

A

Electron transport chain

115
Q

What is chemiosmosis

A

A process that transfers electrons from one carrier to the next , releasing energy, some of which is used to make ATP

116
Q

Photophosphorylation

A

Occurs only in photosynthetic cells. They have a light trapping pigment called chlorophyll that give up electrons. Light energy is converted to chemical energy of ATP and NADH, ETC involved.

117
Q

Metabolic pathway

A

A sequence of enzymatically catalyzed chemical reactions occurring in a cell

118
Q

What is carbohydrate catabolism

A

The oxidation of carbohydrates; breakdown of carbohydrate molecules to produce energy

119
Q

What is the primary source of cellular energy

A

Carbohydrates

120
Q

What substance is the most common energy source by cells

A

Glucose

121
Q

What are the 2 general processes of the metabolism of glucose

A

Cellular respiration and fermentation

122
Q

What are the 3 principle stages of Respiration

A
  1. Glycolysis
  2. Krebs cycle
  3. Electron Transpor Chain
123
Q

What is glycolysis

A

The oxidation of glucose to pyruvic acid with the production of some ATP and energy containing NADH

124
Q

What is the Krebs Cycle

A

Oxidation of acetyl CoA to C02 with production of some ATP, energy containing NADH, and another reduced electron carrier–>FADH2

125
Q

What is electron transfer chain

A

The process of which involves the oxidation of NADH and FADH2 and the transfer of their electrons to generate ATP.

126
Q

Wherebdies the most generation of ATP occur in cellular respiration

A

ETC

127
Q

Is oxygen required for glycolysis

A

No

128
Q

What are the 2 basic stages of glycolysis

A
  1. Preparatory stage

2. Energy conserving stage

129
Q

Glycolysis also known as

A

Embeden- Meyerhof pathway

130
Q

How many pathways are in6in glycolysis

A

10

131
Q

What is the preparatory stage of glycolysis

A

Glucose is split to form (2) glucose-3 phosphate,(2) ATP are used in this process

132
Q

What happens during the energy conserving stage of glycolysis

A

(2) glucose-3 phosphate is oxidized to (2) pyruvic acid, and 2 net ATP, 2 NADH are produced

133
Q

What happens if glycolysis takes place in an anaerobic environment

A

NADH unload onto pyruvate and create lactic acid

134
Q

What are alternatives to glycolysis

A

Bacteria can use another pathway to oxidize glucose:

  1. Penrose phosphate pathway
  2. Entner-Doudoroff Pathway
135
Q

Pentose phosphate pathway

A

Uses pentose instead of hexose and NADPH, Operates with glycolysis, provides means for breakdown of 5 penthouse sugar and glucose

136
Q

What bacteria use pentose phosphate pathway

A

Bacillus subtilis, E. coli

137
Q

Entner Doudoroff pathway

A

Produces 2 NADPH and 1 ATP

Does not involve glycolysis

138
Q

What bacteria use ED Pathway

A

Normally found in gram negative bacteria such as Rhizonium, Pseudomonas, Agrobacterium

139
Q

What are the key features of pentose phosphate pathway

A

Produces important intermediate pentose used in nucleic acids, glucose from C02 in photosynthesis, and certain aa

140
Q

Cellular Respiration

A

An ATP generating process in which molecules are oxidized, liberating electrons for an electron transport chain

141
Q

What is commonly the final electron acceptor in cellular respiration

A

An organic molecule

142
Q

How is ATP generated in cellular respiration

A

By oxidative phosphorylation

143
Q

What are the 2 types of cellular respiration

A

Aerobic and anaerobic

144
Q

What is the FEA for aerobic respiration

A

02

145
Q

What is the FEA for anaerobic respiration

A

Can be either an inorganic molecule other than 02 or an organic molecule (rarely)

146
Q

Aerobic respiration

A

Involves the Krebs cycle, in which a series of biochemical reactions take place and a large amount of potential chemical energy stored in acetyl CoA is released step by step

Microbiology LECTURE (13 decks)

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