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Microbiology Lecture Exam 2

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155 Terms
πŸ˜ƒ Not studied yet (155)
Metabolism
the sum of all chemical reactions that occur in an organism
Catabolism
provides energy and building blocks for anabolism
Anabolism
uses energy and building blocks to build large molecules
Mechanism of enzymatic action
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What factors influence enzyme activity?
temperature, pH, substrate and enzyme concentration, inhibitors
Enzyme inhibitors
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Metabolism
the sum of all chemical reactions that occur in an organism
Metabolic pathway
is a sequence of enzymatically catalyzed chemical reactions in a cell
Metabolic pathway
is a sequence of enzymatically catalyzed chemical reactions in a cell
Enzymes are coded
By genes
Enzymes are coded
By genes
collision theory
states that chemical reactions can occur when atoms, ions, and molecules collide
collision theory
states that chemical reactions can occur when atoms, ions, and molecules collide
activation energy
Is needed to disrupt electronic configurations
activation energy
Is needed to disrupt electronic configurations
reaction rate
is the frequency of collisions with enough energy to bring about a reaction
reaction rate
is the frequency of collisions with enough energy to bring about a reaction
Reaction rate can be increased by ______ or by increasing___________
Enzymes, temperature, pressure
Reaction rate can be increased by ______ or by increasing___________
Enzymes, temperature, pressure
activation E barrier
Activation E (Ea) 1. E need to control bonds into position for a reaction 2. can be heat 3. determines the rate of the reaction a. e.g. if Ea is low enough then reate will ve relatively high
activation E barrier
Activation E (Ea) 1. E need to control bonds into position for a reaction 2. can be heat 3. determines the rate of the reaction a. e.g. if Ea is low enough then reate will ve relatively high
Apoenzyme
Protein
Apoenzyme
Protein
Coenzyme
No protein component
Coenzyme
No protein component
Examples of Coenzymes
NAD+, FAD+, NADP+
Examples of Coenzymes
NAD+, FAD+, NADP+
Holoenzyme
Apoenzyme plus cofactor
2 prominent Enzyme inhibitors
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How do cells phosphorylation ADP to ATP?
Substrate level phosphorylation Oxidative phosphorylation Photophosphorylation
Anabolic pathways use some ATP molecules by
Breaking a phosphate bond
Substrate level phosphorylation
The enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism.
What is an example of substrate level phosphorylation?
ATP production in glycolysis
Oxidation
Loss of electrons
Reduction
gain of electrons
Redox reaction
an oxidation reaction paired with a reduction reaction
In biological systems, the electrons are often associated with
hydrogen atoms
Biological oxidations are often
dehydrogenations
Carbohydrate catabolism
the breakdown of carbohydrates to release energy
What are examples of carbohydrate catabolism?
Glycolysis Kreb's Cycle Electron transport chain
Glycolysis
The energy investment phase of the glycolysis pathway that uses two ATP molecules to phosphorylation glucose forming two gluceralsehyde 3- phosphate molecules (G3P).
The energy payoff phase of Glycolysis harnesses the energy in the-
G3P molecules, production of 4 ATP molecules, Two NADH molecules and 2 pyruvates
What are the two alternatives to Glycolysis pathway
Pentose phosphate pathway Entner Doudoroff pathway
Pentose phosphate pathway
Uses pentoses and NADPH operates with glycolysis
Entner-Doudoroff pathway
Produces NADPH and ATP Does not involve glycolysis Pseudomonas, Rhizobium, Agrobacterium
The Krebs cycle
second stage of cellular respiration, in which pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions
Coenzyme A (acetyl CoA)
A coenzyme used in various biochemical reactions as a carrier of acyl groups. Does not enter Krebs Cycle
Electron Transport Chain (ETC)
series of electron carrier molecules that are in turn oxidized and redialed as electrons are passed down the chain
Chemiosmosis
A process for synthesizing ATP using the energy of an electrochemical gradient produces from the Electron Transport Chain and the ATP synthase enzyme.
aerobic respiration
the final electron acceptor in the electron transport chain is molecular oxygen (O2)
anarobic respiration
final electron acceptor is NOT O2 Yields less energy than aerobic respiration
Fermentation
Process by which cells release energy in the absence of oxygen Microbial metabolism
Fermentation (scientific definition)
Releases energy from oxidation of organic molecules Does not require oxygen Does not use the Krebs cycle or ETC Uses an organic molecule as the final electron acceptor
Yeast is the only microorganism to
Produce only ethanol (and CO2)
Lipid catabolism
-Lipids are hydrolyzed by lipase into Glycerol (later into DHAP) and Fatty Acids (FA), -Fatty Acids are oxidized via the beta-oxidation pathway to make acetyl-CoA. to then enter the kreb cycle
Protein catabolism example
Ureaβ€”β€”β€”β€”>NH3 + CO2
Two types of photosynthesis
oxygenic and anoxygenic
Photo:
Conversion of light energy from the sun into chemical energy.
Synthesis:
Carbon fixation: fixing carbons into organic molecules Light-independent (dark) reaction: Calvin-Benson Cycle
The Calvin cycle is ____________ backwards
Glycolysis
Rubulose biphosphate carbonylase (RuBisCO)
What are the two alternatives to Glycolysis pathway
Pentose phosphate pathway Entner Doudoroff pathway
Pentose phosphate pathway
Uses pentoses and NADPH operates with glycolysis
Entner-Doudoroff pathway
Produces NADPH and ATP Does not involve glycolysis Pseudomonas, Rhizobium, Agrobacterium
The Krebs cycle
second stage of cellular respiration, in which pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions
Coenzyme A (acetyl CoA)
A coenzyme used in various biochemical reactions as a carrier of acyl groups. Does not enter Krebs Cycle
Electron Transport Chain (ETC)
series of electron carrier molecules that are in turn oxidized and redialed as electrons are passed down the chain
Chemiosmosis
A process for synthesizing ATP using the energy of an electrochemical gradient produces from the Electron Transport Chain and the ATP synthase enzyme.
aerobic respiration
the final electron acceptor in the electron transport chain is molecular oxygen (O2)
anarobic respiration
final electron acceptor is NOT O2 Yields less energy than aerobic respiration
Fermentation
Process by which cells release energy in the absence of oxygen Microbial metabolism
Fermentation (scientific definition)
Releases energy from oxidation of organic molecules Does not require oxygen Does not use the Krebs cycle or ETC Uses an organic molecule as the final electron acceptor
Yeast is the only microorganism to
Produce only ethanol (and CO2)
Lipid catabolism
-Lipids are hydrolyzed by lipase into Glycerol (later into DHAP) and Fatty Acids (FA), -Fatty Acids are oxidized via the beta-oxidation pathway to make acetyl-CoA. to then enter the kreb cycle
Protein catabolism example
Ureaβ€”β€”β€”β€”>NH3 + CO2
Two types of photosynthesis
oxygenic and anoxygenic
Photo:
Conversion of light energy from the sun into chemical energy.
Synthesis:
Carbon fixation: fixing carbons into organic molecules Light-independent (dark) reaction: Calvin-Benson Cycle
The Calvin cycle is ____________ backwards
Glycolysis
Rubulose biphosphate carbonylase (RuBisCO)
Holoenzyme
Apoenzyme plus cofactor
Catabolism
provides energy and building blocks for anabolism
Anabolism
uses energy and building blocks to build large molecules
carbohydrate catabolism
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Glycolysis pic
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Krebs cycle pic
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Electron transport chain pic
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Calvin cycle
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Psychotrophs
Grow between 0C and 20 to 30C Cause food spoilage
Physical requirements for microbial growth
1. Temperature most/best between 10-80 C 2. pH most/best between 6.5-7.5 3. Osmotic pressure
Acidophiles grow
In acidic environments
Molds and yeast grow between what pH
pH 5-6
Hypertonic environments ( increase in salt or sugar) cause
plasmolysis
Plasmolysis
This happens when a cell shrinks inside its cell wall while the cell wall remains intact.
extreme or obligate halophiles
require high osmotic pressure
facultative halophiles
tolerate high osmotic pressure
The Effect of Oxygen on the Growth of Various Types of Bacteria
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Toxic oxygen
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Reducing media
Contain chemicals (thioglycolate or oxyrase) that combine O2 Heated to drive off O2
Capnophiles
Microbes that require high CO2 conditions CO2 packet Candle jar
Biofilms are created by
super sticky slime (extracellular matrix) to attach to surface and replicate
Biofilms have the capability to
Communicate via quorum and autoinducers which lead to a new cycle in the bacteria
Biofilm communication triggers
New gene expression and synthesis of new proteins
Biofilm construction results in
Multicellular action consisting of millions of bacteria
70% of infections involve result from
Biofilms
Differential media can
Reveal metabolic activity of growth of microorganism
betahemolysis
Indicated by clear BA plate Complete hemolysis by destruction of RBCs via lysis
Alphahemolysis
BA turns green Secretes toxins causing leakage of hemoglobin which breaks down to green color
Gamma (y) hemolysis
no hemolysis no reaction
Selective media
suppress unwanted microbes and encourage desired microbes
enrichment culture
Inoculating of a specific bacteria from the environment
Freeze drying
Easiest and most effective way to preserve bacterial culture Creates a powder which can be grown back
Sublimation (solid to a gas)
Freeze drying results in
Bacterial growth curve
lag phase, log phase, stationary phase, death phase
lag phase of bacterial growth
The first phase of the bacterial growth curve, in which organisms acclimate to their surrounding; they grow in size but do not increase in number.
Log phase of bacterial growth
population of bacteria increases logarythmically
stationary phase of bacterial growth
Microbial death to birth equilibrium
death phase of bacterial growth
as resources become insufficient, bacteria die off Logarithmic decrease
Enterics (Enterobacteriaceae)
Negative rods, ferment glucose and lactose
Coulter counter
electronically scans a fluid as it passes through a tiny pipette Electronically measure microbe count from a liquid
Ribulose an enzyme that
Runs Calvin cycle and is most abundant enzyme on earth
_________ share nutrients and shelter from harmful factors
Biofilms
culture medium
nutrients prepared for microbial growth
sterile
no living microbes
Inoculum
introduction of microbes into medium
Culture
microbes growing in/on culture medium
Agar
a gel-like polysaccharide compound used for culturing microbes Generally not metabolized by microbes
chemically defined media
exact chemical composition is known
pure culture
contains only one species or strain
Streak plate method
used to isolate pure cultures
Colony
A population of cells arising from a single cell or spore or from a group of attached cells
lypophilization
freeze drying and dehydrated in a vacuum
Reproduction in Prokaryotes
binary fission, budding, conidiospores, fragmentation of filaments
binary fission
A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size
Most Probable Number (MPN)
Estimates cell concentration using dilution series Sets of tubes are incubated; results are recorded and compared to table to give statistical determination
Direct Microbe Count
Uses Petroff-hausser cell counter Microscopic counting of cells within a grid
Light source count
Turbidity estimation of bacterial numbers Uses light source and light sensitive detector to count
Direct methods of measuring microbial growth
plate counts, filtration, direct microscopic count, MPN, coulter counter
Indirect methods of measuring microbial growth
turbidity, metabolic activity, dry weight
Sepsis
refers to microbial contamination
Asepsis
absence of significant contamination
Aseptic surgery
techniques used in surgery to prevent microbial contamination of wounds
Sterilization
removing all microbial life
Commercial sterilization
killing C. botulinum endospores
Disinfection
removing pathogens from fomites (inanimate objects)
Antisepsis is the
Removal of pathogens from living tissue