Microbiology Exam 2
Phenolic compounds are effective against
Most vegetative bacteria, found in detergents, Lysol, work in the presence of organic material, and mycobacterium species
Three main structures targeted by chemicals
Nucleic Acids, Membrane proteins, cytoplasmic membrane
The genus Bdellovibrio
prey on gram negative bacteria by becoming an intracellular parasite
Ethylene oxide is a germicide that kills by reacting with
proteins
Mycoplasmas are
resistant to penicillin. susceptible to lysis by osmotic shock. lacking peptidoglycan
Production of ATP using the energy liberated when electrons from reduced chemical bonds are pass through the electron transport system is generally referred to as
respiration
Endospore-forming gram-positive bacteria are found primarily in __________ habitats.
soil
Competitive inhibition can be overcome by adding excess
substrate
The synthesis of ATP from ADP and Pi, when coupled with an exergonic chemical reaction is called __________ phosphorylation.
substrate-level
Which of the following groups of photosynthetic bacteria are capable of oxygenic photosynthesis?
the cyanobacteria
free energy
the energy released when a chemical bond is broken
Photoautotrophs use light energy directly for
the production of ATP and NADPH.
Cyanobacteria are procaryotes that carry out oxygenic photosynthesis like green plants; this means that
they use water as their electron source. they produce oxygen as a by-product of photosynthesis. they have two distinct photosystems.
EPA regulates chemicals used as
pesticides
A component an organic molecule can be called
Coenzyme
Some enzymes act with the assistance of a nonprotein component known as a
Cofactor
Which of the following is extremely radiation resistant?
Deinococcus
An atom that has a lower affinity(attraction) for electrons than another is described as ______ than another
Less Electronegative
An chemical reaction that requires an input of energy in order to proceed is __________.
endergonic
The major function(s) of the TCA cycle is(are)
energy production and provision of carbon skeletons for biosynthesis of cell components.
The two most important alcohol germicides are __________ and __________.
ethanol; isopropanol
A reaction that releases energy is __________.
exergonic
An agent that specifically kills fungi but not other kinds of microorganisms is also known as a
fungicide
Members of the genus Neisseria cause which of the following human diseases?
gonorrhea
Which of the following are photosynthetic bacteria?
green, blue purple
Members of the genus Rhizobium
grow symbiotically in root nodules of legumes where they fix nitrogen.
Large spherical cells of cyanobacteria that are able to fix atmospheric nitrogen are referred to as
heterocysts
may be used as sources of energy by chemolithotrophs?
hydrogen gas ammonia hydrogen sulfide
Hydrogen peroxide is an effective germicide because
it leaves no residue. it does not damage stainless steel, rubber or glass. it can be used on living tissue.
In aerobic conditions, it takes __________ sugar to produce the same amount of ATP when compared to anaerobic conditions.
less
FDA regulates chemicals used for
medical devices
The disinfectant action of phenol and phenolic derivatives mainly is due to
membrane damage and protein denaturation.
can be used as electron acceptors during anaerobic respiration?
nitrate sulfate carbon dioxide all of the choices
Purines and pyrimidines are precursors for synthesis of
nucleic acids
The chlamydias are
obligate intracellular parasites.
Low temperature storage is bacteriostatic to some bacteria and bactericidal to others. t/f
) True
The pentose phosphate pathway provides
ATP. NADPH. four- and five-carbon sugars for amino acid and nucleic acid synthesis.
Which of the following is a source of carbon skeletons that are used in the synthesis of amino acids?
Acetyl-CoA TCA cycle intermediates glycolysis intermediates Correct Answer all of the choices
What are highly resistant microbes
Bacterial endospores, Protozoan cysts and oocyst, enveloped viruses and naked viruses
The process by which chemolithoautotrophs and photo autotrophs use co2 to synthesis organic compounds is called
Carbon fixation
genera include bacteria with stalks?
Caulobacter
Allosteric regulation
Cells can quickly alter the activity of certain key enzymes, using other molecules that bind reversibly and distort them
Oxidative phosphorylase and
Energy from Exergonic reactions is used to create a proton motive force that drives the addition of P to ADP
Substrate level phosphorylation
Energy released and then Exergonic reaction is used to power the addition of P to ADP
Disinfectants are generally regulated by the
Environmental Protection Agency.
Which of the following is true about enzymes
Enzymes are catalysts that speed up reactions. Most of enzymes are proteins that can be denatured by changes in pH or temperature. Enzymes are highly specific for the substrates they react with and catalyze only one or a limited set of possible reactions with those substrates.
In terms of energy, the series of catabolic reactions by which a cell breaks down glucose are (blank). The energy released is then used to drive anabolic reactions in the cell that are (blank)
Exergonic; Endergonic
Antiseptics are generally regulated by the
FDA
In blank, cells breakdown glucose via glycolysis and then use pyruvate or a derivative as a terminal electron acceptor
Fermentation
Photosynthetic organisms use the light dependent reactions to accomplish to task
Generate ATP via photophosphorylation and generate reducing power
The three central metabolic pathways that gradually oxidize glucose to CO2 are
Glycolysis, the pentose phosphate pathway, the TCA cycle
Competitive inhibition
Inhibitor binds to the active site of the enzyme, blocking access of the substrate to that site. Competitive inhibitors such as sulfa drugs are used as antibacterial medications.
Noncompetitive inhibition (by regulatory molecules)
Inhibitor changes the shape of the enzyme, so that the substrate can no longer behind the active site. This is a reversible action that cells use to control the activity of allosteric enzymes.
Noncompetitive inhibition by enzyme poisons
Inhibitor permanently changes the shape of the enzyme, making the enzyme nonfunctional. & Poisons such as Mercury are used in certain antimicrobial compounds.
Gamma radiation
Is used to sterilize some food products.
Until the optimal temperature is reached, each 10°C rise in temperature has what approximate affect on the speed of enzymatic reactions?
It doubles the rate of the reaction
The TCA cycle completes the (blank) of glucose
Oxidation
In aerobic respiration, what serves as the terminal electronic acceptor
Oxygen
A brief heat treatment that reduces the number of spoilage bacteria and kills pathogens is
Pasteruization
A high solute or hypertonic solution, damages microbial cells causing
Plasmolysis
Some members of this group can use inorganic chemicals such as hydrogen sulfide and ammonia for energy
Prokaryotes only
Coxiella burnetii is responsible for
Q-fever.
Which of the following genera grow symbiotically within root nodules of legumes as nitrogen-fixing bacteroids?
Rhizobium
Precursor metabolites
Serve as carbon skeletons from which subunits of macromolecules can be made
The destruction or removal of all viable organisms is called
Sterilization
What part of the cell is changed by propionic, sorbic and benzoic aids affect?
The cell membrane function
Oxidative phosphorylation
The mechanism by which cellular respiration uses the reducing power generated in glycolysis, the transition step and the TCA cycle to synthesize ATP
Glycolosis
The pathway splits glucose and oxidizes it to form two molecules of pyruvate. Provides the cell with a small amount of ATP, some reducing power and six precursor metabolites.
Photophosphorylation
The suns radiant energy and any electron transport chain create a proton motive force that drives the addition of P to ADP
Ultraviolet radiation is an effective means of sterilizing surfaces (T/F)
True
Unlike the electrons carried by NADP H, the electrons carried by NADH and FADA
Used to generate proton motive force, transferred to the electron transport chain, used to produce ATP by oxidative phosphorylation
Unlike the electrons carried by NADH AND FADH, The electrons carried by NADP H are
Used to reduce compounds during biosynthetic reactions
Triclosan
a Phenolic, widely used in deodorant, soaps, lotions and toothpaste
The energy required to bring the substrates of a reaction together in the correct way to reach the transition state is called
activation energy
The substrate of an enzyme binds at the
active site
The synthesis of complex molecules from simpler ones with the input of energy is called
anabolism
The prevention of infection caused by microorganisms is called
antisepsis.
Members of the genus Pseudomonas
are aerobes that mineralize a wide variety of organic compounds.
Most myxobacteria
are micropredators because they secrete digestive enzymes that lyse bacteria and yeasts. have the ability to aggregate and form a fruiting body under conditions of nutrient limitation. produce desiccation resistant dormant myxospores.
Members of the genus Lactobacillus
are normal flora of the human body in mouth, intestinal tract and vagina.
You are working in a government laboratory in charge of destroying bioterrorism materials. An envelope containing the spore-forming bacterium that causes anthrax must be safely destroyed. What would be the best method for ensuring that the organism is killed?
autoclave
In the TCA cycle, two carbons are removed from citric acid in the form of __________, thereby regenerating oxaloacetate to complete the cycle.
carbon dioxide
Ionizing radiation kills microorganisms by
damaging DNA cytoplasmic membranes. producing reactive oxygen species.
Enzymes catalyze a reaction by
decreasing the activation energy of the reaction.
Although similar to eucaryotic photosynthetic organisms, cyanobacteria are different because they
do not have chloroplasts.
The infectious stage of chlamydiae is called a(n) _________ body
elementary
Mitochondrial electron transport takes place
on the inner mitochondrial membrane