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173 Cards in this Set

  • Front
  • Back
Carbon
To synthesize organic components
Energy Source
Needed for living processes which require energy
Nitrogen
For synthesis of proteins and amino acids
Phosphorous
For synthesis of phospholipids and nucleic acids.
Sulfur
For synthesis of some proteins.
Trace Elements
Cofactors for enzymes.
Water
Makes up 80% of the cytoplasm, solvent and suspending agent, and is required for some chemical reactions.
List 5 elements required by microbes in moderate amounts
Sodium, Calcium, Iron, Magnesium, and Potassium
Autotroph
Microbes that can use CO2 as their only carbon source.
Heterotroph
Microbes that require one or more organic molecules for a carbon source.
Chemotroph
Microbes that oxidize organic or inorganic molecules for energy.
Phototroph
Microbes that use light as an energy source.
Nutrient Medium
Growth suspension used to cultivate microbes.
Chemoautotrophs
Microbes that use CO2 as a carbon source and can oxidize inorganic molecules for energy. Iron bacteria and Nitrogen bacteria in the soil are examples.
Chemoheterotrophs
Microbes that use organic molecules as a carbon source and can oxidize organic molecules for energy. Most bacteria, fungi, and protozoa are of this type.
Photoautotrophs
Microbes that use CO2 as a carbon source and light as an energy source. Algae are an example.
Photoheterotrophs
Microbes that require one or more organic molecules as a carbon source and use light as an energy source. Purple Nonsulfur Bacteria are an example.
Chemically Defined Media
Media in which the exact composition is known, most nutrients can be supplied as salts or sugars, and they provide minimal nutritional requirements for some microbes. Glucose Agar is an example.
Complex Media
Media that contains 1 or more complex nutrients such as proteins or peptone; nutrient molecules vary slightly in each preparation. Nutrient Agar is an example.
Enriched Media
Media that contains a complex medium plus plant or animal extracts; used to cultivate fastidious heterotrophs which have complex nutrient requirements. Blood Agar and Yeast Extract Agar are examples.
Selective Media
Media that contains certain chemicals that can inhibit some groups while permitting others to grow; antibiotics may be added for selection of specific microbes. MacConkey Agar is an example.
Differential Media
Media that allows for visible distinction of different groups and may contain carbohydrates and a pH indicator. EMB Agar is an example.
What is agar and what is its function in microbiological media?
a. It is a polysaccharide extracted from red algae. Bacteria cannot digest agar, so it serves to help microbes grow by giving them something to extract nutrients from, but not digest.
b. Serves a solidifying agent for nutrient broths.
Acidophile
Microbes that have optimum growth between a pH of 0 and a pH of 6. Molds and yeasts are examples.
Alkalophile
Microbes that have optimum growth between a pH of 8 and pH of 14. Not many bacteria are considered alkalophiles.
Neutrophile
Microbes that have optimum growth between a pH of 6 and a pH of 8. Most microbial species are neutrophiles.
pH
Concentration of hydrogen ions. (H+)
Buffer
Solutions that maintain constant pH.
Cardinal Temperatures
i. Maximum Temperature – Highest temperature at which growth occurs. This is the ending point of growth.
ii. Minimum Temperature – Lowest temperature at which growth occurs. This is the beginning point of growth.
iii. Optimum Temperature – Temperature at which best growth occurs.
Psychrophile
Microbes that have optimum growth between 0oC and 20oC. These microbes are found on the ocean floor and in Polar Regions.
Mesophile
Microbes that have optimum growth between 20oC and 40oC. This group includes most microbial species including normal and pathogenic.
Psychrotroph
This group of microbes is a subgroup of Mesophiles in which they can grow below 20oC, but are optimum between 20oC and 40oC. This group can spoil food in refrigerators.
Thermophile
Microbes that have optimum growth between 40oC and 100oC. This group is found in compost piles, hot springs, and geysers.
Hyperthermophile
Microbes that have optimum growth between 80oC and 120oC. These microbes are found around vents in the ocean floor.
PCR
Stands for Polymerase Chain Reaction; process of DNA replication at high temperatures. Used in Thermophiles.
Aerobe
Microbe that require some level of free 02.
Obligate Aerobe
Microbes that require atmospheric level of free oxygen or 21%.
Microaerophile
Microbes that require less than 21% of free O2 for optimal growth.
Anaerobe
Microbes that do not require free O2.
Facultative Anaerobe
Anaerobic microbe that uses free O2 when available, but can also grow without it.
Aerotolerant Anaerobe
Also known as the fermenters, these are microbes that never use free O2 and are indifferent to it.
Obligate Anaerobe
Microbes that cannot tolerate free O2 and will die in its presence.
Capnophile
Microaerophiles that also require 3% to 10% CO2 for optimal growth.
Facultative Halophile (Halotolerant)
Microbes that grow in isotonic environments and in 2%-20% salt.
Obligate Halophile
Microbes that require 9%-30% salt.
Osmosis
Diffusion of water across a semipermeable membrane.
Osmophile
Microbes that grow in high sugar or salt environments.
Plasmolysis
Shrinking of cytoplasm away from the cell wall.
Turgor Pressure
Pressure created by osmotic flow of water into a cell with a cell wall. The cytoplasm of the cell begins to push against the cell wall and creates this pressure.
Explain how extremes in pH and excessive heat inhibit microbial growth.
a. Extreme pH – Denatures enzymes to inhibit growth.
b. Excessive Heat – Growth will stop if a temperature is too high or too low because certain microbes cannot function under irregular conditions.
What are SOD and catalase and how do they affect the growth of obligate anaerobes?
Obligate anaerobes lack the Super Dioxide (SOD) and catalase needed to break down toxic products formed when O2 is used.
What is the Pasteur Effect and in which group of microbes is it observed?
Facultative microbes can growth with or without oxygen. However, they grow much better with oxygen because it creates more ATP for energy and replication.
Isotonic Environment
Contains the same concentration of solute and water as cytoplasm; no osmosis will occur. The cell will neither gain water nor lose water.
Hypotonic Environment
Contains a lower concentration of solute and a higher concentration of water than cell. Produces Turgor Pressure in cells with a cell wall, and lysis in those without cell walls.
Hypertonic Environment
Contains a higher concentration of solute and lower concentration of water than cells. Causes plasmolysis and can severely inhibit growth,
Which of the environment (Isotonic, Hypertonic, Hypotonic) had the greatest effect on microbial growth?
a. Isotonic environments help with growth.
b. Hypertonic environments inhibit growth the most.
Describe the process of binary fission.
a. Binary fission is the most common type of reproduction in bacteria. It takes place when one bacterium divides to produce two new cells. It is different from mitosis in that binary fission involves neither centrioles nor spindles and is usually faster than mitosis.
b. Cell elongates and DNA is replicated. The cell wall and plasma membrane begin to divide. A cross wall begins to form completely around divided DNA. The cells then separate.
What factors cause death in an aging bacterial culture?
Death in cells is caused by depletion of nutrients and buildup of wastes at toxic levels.
Lag Phase
Cells adjust to environment and prepare to divide. No binary fission occurs.
Log Phase
Bacteria divide at a constant maximum rate.
Stationary Phase
Growth rate equals death rate. The number in population is constant. (1010/ml)
Decline Phase
Bacteria die at an accelerated rate.
Generation Time
Interval for doubling number. Maintained by continuous culture processes for genetic engineering and synthesis of antibiotics.
Titer
Number of bacteria per ml of culture.
Direct Methods
Cell counts
Counting Chamber Method
Method of a depression in the slide with a grid on the bottom, so that each section over the grid has a specific volume. When counting the number in the grid section, the number of volume per grid is counter.
Coulter Counter
Electrical counter of microbes.
Turbidity
Increased cloudiness indicates increased titer.
Serial Dilution
Dilution from one tube from the next to the next.
What is the relationship between turbidity and the titer of a culture?
The more titer on a culture would indicate an increase in turbidity.
Briefly explain the standard plate count.
a. Serial dilution of sample or culture.
b. Diluted samples added to agar medium.
c. Culture incubated at 37oC for 24 hours.
d. Colonies counted and titer calculated.
What are pure culture techniques?
Used to separate mixed cultures into pure subcultures.
Why can an isolated colony be used to produce a pure subculture?
Isolated colony contains microbes from one original cell and is a pure culture.
Streak Plate Technique
A mixed culture is streaked on agar medium. The culture is then incubated at 37oC for 24 hours. Samples from isolated colonies removed and added to sterile media producing pure subcultures. Streaking dilutes and isolates colonies.
Enrichment Technique
A mixed culture is streaked on chemically defined media containing a restrictive carbon source for enrichment. The culture is then incubated at 37oC for 48 hours. The culture is then removed from isolated colonies and added to sterile media. This technique uses a carbon source to restrict growth.
Metabolism
All chemical reactions occurring in microbes.
Anabolism
Synthetic metabolism that forms new chemical bonds.
Catabolism
Degradative metabolism in which chemical bonds are broken down.
Activation Energy
The minimal amount of energy required for a chemical reaction.
Endergonic
Requiring energy.
Exergonic
Release of a surplus of energy.
Enzyme
Biological catalysts that reduce activation energy so reactions can occur at temperatures compatible with life.
Active Sites
Areas where substrates attach. They are present on all enzymes.
Lock-and-Key Mechanism
Demonstrates how enzymes and substrates must fit together and have complimentary surfaces in order for them to work.
Allosteric Sites
Areas where molecules other than substrates attach and combine. They usually inhibit the enzyme and are often called allosteric inhibitors.
Simple Enzymes
Proteins with catalytic activity.
Conjugated Enzymes
Inactive protein (apoenzyme) plus cofactor.
Cofactor
Foundation for conjugated enzymes. May be a metallic ion or coenzyme.
Coenzyme
Organic cofactors.
Competitive Inhibitors
Chemicals that compete with substrates to bind to an active site. They change the end product that the enzyme produces.
Noncompetitive Inhibitors
Chemicals that bind to allosteric sites or cofactors. Shuts down the enzyme’s processes.
Metabolic Pathway
Normal functioning of an enzyme’s metabolic activity.
Explain how feedback inhibition regulates enzyme activity and synthesis of an end product.
The excess end product combines with allosteric sites of the first enzyme. This will stop the processes of the enzyme. Inhibition stops when the entire excess product is used up.
Identify 2 ways enzymes are named.
a. By the reaction they catalyze. Oxioreductase)
b. By the substrate converted. (Lipase)
Exoenzymes
Enzymes that are secreted into the environment. Most have digestive functioning in which they break down large nutrients so absorption can occur.
Endoenzymes
Function within microbes.
Constitutive Enzymes
Enzymes produced at a constant rate at all times.
Inducible Enzymes
Enzymes produced only when the substrate is present.
What is the common ending for the names of enzymes?
-ase
Identify three external energy sources used by microbes.
a. Oxidation of organic molecules.
b. Oxidation of inorganic molecules.
c. Sunlight.
Substrate Phosphorylation
Removal of high energy bonds directly from substrate to ADP.
Oxidative Phosphorylation
Occurs in the ETC; Chain of oxidation-reduction reactions; Produces 90% of ATP in respiration.
Photophosphorylation
Similar to Oxidative Phosphorylation, but occurs in light reaction of photosynthesis.
Light Reaction
Light is absorbed by pigments in organelles producing ATP and NADPH. Light reactions are dependent upon the sun.
Dark Reaction
Light reaction in photosynthetic organelles that uses the products of the light reactions in the Calvin-Benson cycle to produce organic molecules.
Oxygenic Photosynthesis
Process of photosynthesis in which a cell uses oxygen as a reactor, and thus produces oxygen in the product.
Anoxygenic Photosynthesis
Process of photosynthesis in which a cell does not use Oxygen in its reaction, therefore it does not produce oxygen in the outcome.
Photolysis
Splitting of H2O in noncyclic photophosphorylation. Major source of atmospheric oxygen.
List two different pathways by which microbes oxidize organic molecules to produce ATP.
a. Respiration.
b. Fermentation.
What is the ETS and where is it found in eukaryotes and in prokaryotes?
a. It is a chain of coenzymes that receive H2 from NADH+H+ and FADH2. It transports e- to a terminal acceptor which is then reduced.
b. It is located on the inner plasma membrane of prokaryotes.
c. It is located in the mitochondria in eukaryotes.
Explain the difference between aerobic and anaerobic respiration.
a. Aerobic – Terminal receptor is oxygen.
b. Anaerobic – Terminal receptor is anything other than oxygen.
Glycolysis
Glucose (6 carbon sugar) + 2 ATP  2 Pyruvic Acid (3 carbon sugar) + 2 NADH + H+ + 4 ATP (substrate phosphorylation.) Then, 2 NADH + H+ go into the electron transport chain and produce 6 ATP through oxidative phosphorylation. Net energy gain of 8 ATP.
Transition Reaction
2 Pyruvic Acid (3 carbon sugar) (from Glycolysis)  2 Acetyl – CoA (2 carbon sugar) + 2 NADH + H+ + 2 CO2. Then the 2 NADH + H+ go through the electron transport chain to produce 6 ATP through oxidative phosphorylation. Net energy gain of 6 ATP. Very similar to Glycolysis but with Pyruvic Acid as a reactant.
Kreb's Cycle
1 Acetyl – CoA from the Transition Reaction is transferred into the Krebs or Citric Acid cycle where it is broken down into 2 CO2 + 3 NADH + H+ + 1 FADH2 + 1 ATP through substrate phosphorylation. The 3 NADH + H+ are then transported through the electron transport chain where they produce 9 ATP through oxidative phosphorylation. The 1 FADH2 is also transported through the electron transport chain where it creates 2 ATP through oxidative phosphorylation. Net energy gain per cycle is 12 ATP, with a total energy gain of 24 ATP because the transition reaction creates 2 Acetyl – CoA which is the reactant.
Represent aerobic respiration of glucose with a single balanced equation.
C6H12O6 + 6O2 --------> 6H2O + 6CO2 + 38 ATP + Heat
What percent of the energy in glucose is found in the ATP molecules produced in respiration?
40%
Terminal Electron Receptor
Molecule that accepts electrons from the ETC.
Oxidation-Reduction Reaction
One molecule loses H2 or an electron which another accepts. Also referred to as simply oxidation. OIL RIG: Oxidation is loss of electrons, Reduction is gain of electrons.
Chemiosmosis
The process by which ATP is produced during electron transport while protons move across the plasma membrane through channels.
Fermentation
Oxidation of organic molecules that does not use an ETC.
Calvin-Benson Cycle
The process of breaking down CO2 into glucose and other sugars. This process is the opposite of respiration.
Identify five differences between respiration and fermentation.
-Fermentation-No Electron Transport Chain, Uses Substrate Phosphorylation, Incomplete Oxidation, Organic products as electron receptors, Typically anaerobic.
-Respiration- Electron Transport Chain, Uses Oxidative and Substrate Phosphorylation, Complete Oxidation, Inorganic products as electron receptors, Can be anaerobic or aerobic
What molecule acts as a hub for fermentation?
Pyruvic Acid
Homolactic Fermentation
Process of fermentation that produces only lactic acid.
i. It has a net energy gain of 2 ATP.
ii. Glucose + 2 ATP  2 Pyruvic Acid  2 Lactic Acid + 4 ATP.
iii. Streptococcus & Lactobacillus utilize this method.
Mixed-Acid Fermentation
Process of fermentation that produces products other than lactic acid.
i. It has a net energy gain of 2 ATP.
ii. Glucose + 2 ATP  2 Pyruvic Acid  Variety of products + 4 ATP.
iii. Escherichia coli utilize this method.
Alcoholic Fermentation
Process of fermentation that produces ethyl alcohol and CO2.
i. Glucose + 2 ATP  2 Pyruvic Acid + 4 ATP  2 Ethyl Alcohol + 2 CO2.
ii. Yeasts are an example as they are used in brewing and distilling of certain alcohols. Also used in baking.
Explain how chemoautotrophs produce ATP and synthesize their organic molecules.
Chemoautotrophs are generally aerobes that synthesize organic molecules through the Calvin-Benson cycle. They utilize an ETC to produce ATP and can only produce 1 ATP per electron pair that passes through the chain. Mostly chemoautotrophs oxidize inorganic molecules such as ammonia, nitrite, ferrous ions, hydrogen sulfide, and sulfur compounds.
Describe the differences in photosynthetic organelles and photosynthetic pigments in the following: Algae, Cyanobacteria, and Photosynthetic Sulfur Bacteria
a. Algae – Algae uses chloroplasts as an organelle and chlorophyll a as a pigment.
b. Cyanobacteria – Cyanobacteria uses thylakoids as an organelle and chlorophyll a as a pigment.
c. Photosynthetic Sulfur Bacteria – Photosynthetic Sulfur Bacteria use chlorosomes as an organelle and bacteriochlorophyll as a pigment.
Explain the connection between the light reaction and the dark reaction of photosynthesis.
The light reaction produces NADPH and ATP which are used in the dark reaction through the Calvin-Benson cycle along with CO2 to produce glucose.
Identify the products of the light reaction in the following: Algae, Cyanobacteria, Photosynthetic Sulfur Bacteria, and Photosynthetic Non-Sulfur Bacteria
a. Algae – ATP, NADPH &, Oxygen.
b. Cyanobacteria – ATP, NADPH &, Oxygen.
c. Photosynthetic Sulfur Bacteria – ATP, NADPH, & Sulfur.
d. Photosynthetic Non-Sulfur Bacteria – ATP, NADPH, & Oxygen.
Cyclic Photophosphorylation
Light enters the organelle and excites the electrons. The electrons then pass from the chlorophyll through carriers back to the same chlorophyll to produce ATP.
Noncyclic Photophosphorylation
This process requires 2 systems containing chlorophyll, Photosystems I & II. As light enters the organelle, it excites the electrons in Photosystem I and is released. It passes through carriers to produce NADP which then produces ATP and NADPH. The excited electrons in Photosystem II also move, passing from their own chlorophyll to the chlorophyll in Photosystem I which then neutralizes its charge by chemiosmosis, and is ready to be recharged by the light to continue from the beginning. The empty space in Photosystem II is then filled from an electron given from a reducing agent (H2O, H2S, etc.). When a chloroplast splits a water molecule to place the hydrogen into Photosystem II, this is called photolysis which is a major source of O2 in the atmosphere.
Identify four unique characteristics of the viruses.
a. They are noncellular.
b. They are the smallest microbes.
c. They only have 1 type of nucleic acid.
d. They are obligate intracellular parasites.
Capsid
Protein coat surrounding core made of subunits called capsomeres.
Core
Central area containing nucleic acid
Envelope
Lipoprotein layer around capsid derived from host cell’s plasma membrane and has projections called spikes for attachment.
Nucleocapsid
Also called naked viruses. They contain only a core containing nucleic acids and a capsid.
Phage
A virus that only infects bacteria. Also called bacteriophages.
Virion
A complete virus that can infect a host.
Viral species
Group of viruses sharing the same genetic information and infecting the same hosts.
List the three groups of hosts that are infected by viruses.
a. Animals
b. Plants
c. Bacteria
Explain the difference between naked viruses and enveloped viruses.
a. Naked Viruses – Naked viruses only include a core and a capsid.
b. Enveloped Viruses – Enveloped viruses contain a core and capsid as well as an envelope which can also have spikes attached to it.
What part of some enveloped viruses is derived from their host cell?
Plasma Membrane
Identify the function of the spikes of enveloped viruses.
They are used for attachment.
Describe three morphological groups of viruses.
a. Polyhedral Viruses – Virus that has a many sided capsid. Hepatitis B is an example.
b. Helical Viruses – Virus that has a tubular capsid composed of spirally arranged capsomeres. Influenza is an example.
c. Complex Viruses – Virus that has a capsid with a complex structure. Bacteriophages are an example.
List three characteristics used to classify viruses.
a. Type of nucleic acid.
b. Type of replication.
c. Morphology.
Describe three methods used by viruses to penetrate host cells.
a. Endocytosis – Common method in animal viruses. Produces a pocket to take in the cell.
b. Fusion – Envelope fuses with the plasma membrane.
c. Injection – Viruses inject their DNA into the host cell.
Adsorption
Attachment of virus to host cell, requires complementary receptors on host.
Uncoating
Separation of capsid from viral nucleic acid.
Eclipse Period
The point when there are no complete virions in the host cell, usually after uncoating.
Early Proteins
First viral specific proteins produced in the host; they inhibit normal protein synthesis in the host and act as enzymes for replication of viral nucleic acids.
Late Proteins
Proteins made by the host cell infected by the virus that serve as capsomeres for the new viruses to create capsids.
Reverse Transcriptase
Enzyme used by retroviruses to copy RNA to DNA.
Provirus
Double-stranded viral DNA that attached to host chromosomes.
Assembly
The process of putting together new viruses in a host cell.
Explain typical replication of viral nucleic acid and how replication in the retroviruses differs.
a. Viral Replication – DNA viruses replicate DNA & assemble new viruses in nucleus. RNA viruses replicate RNA & assemble new viruses in cytoplasm. Replicated RNA is used to produce more viral RNA.
b. Retroviruses – Carries reverse transcriptase which helps the viral RNA create a single stranded DNA molecule that is complimentary. This complimentary DNA strand then forms another complimentary strand creating a double-stranded DNA molecule. This double-stranded DNA then attached to the host’s chromosome (provirus) and one strand of this attached DNA is used to synthesize a new viral RNA.
About how many new viruses are produced in one cycle of infection by a phage? By an animal virus?
a. Phage – 100 - 200 new viruses.
b. Animal Virus – 3,000 - 100,000 new viruses.
Describe two methods by which new viruses are released from host cells and identify the type of virus that utilized each.
a. Lysis of the host cell is the first method. The cell ruptures when too many new viruses have been produced inside of the host cell and it can no longer house them all. Phages and naked animal viruses are examples.
b. Viruses can be released individually. This process is called budding, and usually occurs when a new naked virus moves to the inner edge of the host cell and begins pushing outward so that eventually the new virus takes along with it part of the host’s cell membrane. This new cell membrane serves as the new virus’s envelope. All enveloped viruses are released by budding.
Interferons
Proteins produced by infected cells that protect other cells from the virus. They stimulate the synthesis of antiviral proteins.
Inclusion Bodies
Granules which are often viral particles found in infected cells.
Congenital Effects
Damage to a developing fetus caused by a virus.
Cell Transformation
Cells lose their normal contact inhibition and do not stop growing when they reach an edge.
Oncogenic Viruses
Viruses that produce malignant and nonmalignant tumors by cell transformation.
Latent Viral Infection
A virus that infects a person and remains dormant in the host until later when it can re-infect them.
Viral Plagues
Clear areas on carpet of host cells due to replication and lysis. These are destroyed host cells.
Lytic Phage
Bacteriophage that injects DNA into a bacterium, replicates, & then causes lysis of the host.
Lysogenic (Temperate) Phage
Bacteriophage that injects DNA into the cell and the DNA attaches to the host’s chromosomes.
Lysogenic Bacterium
A bacterium that has a lysogenic phage’s DNA attached to its chromosome which turns it into a pathogen.
Prophage
The attachment of the phage’s DNA to the host’s chromosome.
Lysogenic Conversion
Prophage DNA produces a new characteristic in the host by changing its genetic makeup.
Describe three methods used for cultivation of animal viruses.
a. Cell Cultures – Viruses multiply within animal cells growing nutrient solution.
b. Duck & Chuck Embryos – Viruses introduced into embryonic membranes and multiply in cells. Used for vaccines, namely influenza.
c. Live Lab Animals – Live animals are required for some viruses because they are needed to study immune responses from live white blood cells.
Explain the structure and diseases caused by the following: Prions and Viroids
a. Prions – Proteinaceous infectious particles. They are proteins that can cause some fatal diseases of the central nervous system. They are transmitted from one infected individual to another. They are the most difficult infectious particles to destroy. Examples are Mad Cow Disease (BSE), Kuru, & Creutzfeldt-Jacob Disease in humans.
b. Viroids – Short pieces of RNA that cause some plant diseases. Examples are Cadang-Cadang viroid of coconut tress & the potato spindle tuber viroid.
What group of viruses is known to cause latent infections?
Herpes Virus