Chapter 5 - Microbial Metabolism Flashcards

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1
Q

Metabolism

A

-the buildup and breakdown of nutrients within a cell
-sum of all chemical reactions in a living organism
-provide energy and create substances that sustain life
-the same through microbes and humans

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2
Q

Enzymes

A

-biological catalysts
-catalyze reactions for specific molecules called substrates
-accelerate reactions by lowering activation energy
-conjugated proteins: need cofactors to work
-enzymes are specific for reactions: they find their substrate with a lock and key fit

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3
Q

Products

A

-the result of transforming substrates

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4
Q

Catabolic Pathways

A

-break down macromolecules into simple components
-release energy in the process

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5
Q

Anabolic Pathways

A

-build up macromolecules by combining simpler molecules
-use energy in the process

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6
Q

Hydrolytic Reaction

A

-use water
-chemical bonds are broken

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7
Q

Exergonic Reaction

A

-produce more energy than they consume

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8
Q

Activation Energy

A

-amount of energy required to disrupt stable electronic molecules

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9
Q

Catalysts

A

-substances that speed up a reaction without being permanently altered themselves

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10
Q

Simple Protein Enzyme

A

-one of the two types of enzymes
-consists entirely of proteins

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11
Q

Conjugated Protein Enzymes

A

-one of the two types of enzymes
-consist of both a protein portion (Apoenzyme) and nonprotein (cofactor)

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12
Q

Apoenzyme

A

-inactive by themselves
-protein portion (chapter 2)

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13
Q

Cofactor

A

-the activator of apoenzyme
-non-protein component

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14
Q

Inorganic Cofactor

A

-magnesium, iron, calcium ions

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15
Q

Coenzyme (Organic Cofactors)

A

-derived from vitamin B
-used to carry electrons and proteins to oxidative phosphorylation
-ie. NAD

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16
Q

Holoenzyme

A

-whole, active enzyme
-can carry out metabolic activity
-apoenzyme + cofactor = holoenzyme

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17
Q

NAD+

A

-Nicotinamide adenine dinucleotide
-vitamin B derivative
-electron carrier in catabolic reactions

18
Q

NADP+

A

-nicotinamide adenine dinucleotide phosphate
-vitamin B derivative
-electron carrier in anabolic reactions

19
Q

Temperature on Enzymes

A

-bell shaped curve
-enzyme activity declines beyond optimal temperature
-optimal temp. usually between 35-45

20
Q

Denaturation

A

-breakage of hydrogen bonds
-protein unravels and becomes useless

21
Q

pH

A

-bell shaped curve
-enzyme activity declined above or below optimum pH
-extreme changes can cause denaturation
-acids alter protein structure because because H+ competes with bonds

22
Q

Substrate Concentration

A

-graph increases till it plateaus
-high substrate concentration: saturated
-plateau occurs when all active sites are occupied so if you add more substrate, nothing further will happen

23
Q

Inhibitors

A

-compete for active site on protein
-have same chemical makeup and mimic the enzyme

24
Q

Competitive Inhibitor

A

-fill the active site of an enzyme and compete with the normal substrate
-can be reversible or irreversible
-can overcome by increasing substrate concentration
-ie. Sulfa

25
Q

Sulfanilamide (Sulfa)

A

-mimics/inhibits PABA (Para-amino-benzoic-acid)
-used to treat bacterial infections (usually UTIs)
-PABA produces folic acid which makes DNA and RNA nucleotides
-Sulfa stimulates no folic acid which prevents DNA and RNA and leads to cell death

26
Q

Why sulfa usually works on humans?

A

-humans get folic acid from food and don’t use PABA like bacteria
-sulfa only affects bacterial cells

27
Q

Noncompetitive Inhibitors

A

-don’t compete with substrate for active site
-interact with another part of the enzyme
-binds to allosteric site to alter active site shape making it nonfunctional
-can be reversible or irreversible

28
Q

Feedback Inhibition

A

-noncompetitive inhibitors
-stops cell from making more of a substance than it needs
-shut down the assembly line by stopping the first worker
-ie. E. coli

29
Q

E. coli

A

-feedback inhibition
-inhibits the amino acid needed for cell growth

30
Q

Glycolysis

A

-process where glucose is broken down into pyruvic acid to produce energy
-products: pyruvate x2, ATP x2, NADH x2, H2O x2
-takes place in cytoplasm
-doesn’t require oxygen

31
Q

Krebs Cycle

A

-series of enzyme catalyzed reactions
-2 cycles needed
-occurs in mitochondrial matrix in eukaryotes
-occurs in cytoplasm in prokaryotes
-x2 acetyl-CoA is used up and forms x4 CO2, x6 NADH, x2 FADH2, x2 ATP

32
Q

Electron Transport Chain

A

-electrons pass through proteins in inner mitochondrial membrane (eukaryote) and in plasma membrane (prokaryote)
-release energy through a series of redox reactions
-32 ATP produced

33
Q

Oxidation-Reduction Reactions

A

-oxidation (molecule A): removal of an electron (and a proton) from a molecule that produces energy
-reduction (molecule B): gains an electron (and a proton)
-each time one molecule is oxidized another is reduced
-the foundation of glycolysis and the krebs cycle

34
Q

Role of Hydrogen (Dehydrogenation)

A

-since an electron and a proton are lost, that is equivalent to one H+ atom
-so: molecule A loses a H+ and molecule B gains a H+

35
Q

ATP Generation

A

-via phosphorylation of ADP (addition of a P)
-ADP + P + energy = ATP

36
Q

Substrate Level Phosphorylation

A

-energy from the transfer of a high energy P to ADP generates ATP
-substrate ~ (high energy bond that can be broken) P + ADP = substrate + ADPᴾ (ATP)

37
Q

Oxidative Phosphorylation

A

-electrons are transferred (oxidation) from organic compounds to electron carriers (reduction) (ie. NAD+ or FAD)
-electrons passes through the ETC, releasing energy used to generate ATP

38
Q

Photophosphorylation

A

-only in photosynthetic cells
-light causes chlorophyll to give up electrons
-energy is released from the electron transfer (oxidation) of chlorophyll
-generates ATP

39
Q

Aerobic Respiration

A

-has to have oxygen as the final electron acceptor in the ETC
-ATP yield: 36 eukaryotes, 38 prokaryotes
-most bacteria are aerobic
-humans can be aerobic

40
Q

Role of O2 in Anaerobic Respiration

A

-absorb unusable byproducts (electrons)

41
Q

Anaerobic Respiration

A

-oxygen not required
-final electron acceptors: NO3-, SO43-, CO3-
-glycolysis occurs
-yields less energy because only part of krebs cycle operates
-ATP yield varies
-humans can do sometimes
-ie. clostridium bacteria

42
Q

Fermentation

A

-uses organic molecule as final electron acceptor
-can be in presence of oxygen or not
-glycolysis only (ATP = 2)
-no krebs cycle or ETC
-ie. Lactobacillus: makes lactic acid, yeast: makes Co2 and ethanol
-lactic acid, CO2, ethanol would be the electron acceptors