Microbiology Lecture Exam 2

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

What factors influence enzyme activity?

temperature, pH, substrate and enzyme concentration, inhibitors

Enzyme inhibitors

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

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

Urea————>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

Urea————>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

Glycolysis pic

Krebs cycle pic

Electron transport chain pic

Calvin cycle

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

Toxic oxygen

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