MODULE 3 MULTI-CHOICE Flashcards
- Which of the following is not an essential macronutrient for the growth of microbes:
(a) Carbon
(b) Nitrogen
(c) Phosphorus
(d) Sulfur
(e) All are essential macronutrients
ALL ARE ESSENTIAL MACRONUTRIENTS
- Cyanobacteria carry out oxygenic photosynthesis producing oxygen as a byproduct
from the oxidation of water, which serves as the electron donor for the light-dependent
reactions. How would cyanobacteria be classified?
(a) chemoorganoautotroph
(b) chemoorganoheterotroph
(c) photolithoheterotroph
(d) photoorganoautotroph
(e) photolithoautotroph
PHOTOLITHOAUTOTROPH
- Which of these is true for a chemolithotroph?
(a) inorganic molecules as energy sources and inorganic carbon as a carbon source
(b) organic molecules as electron sources and inorganic carbon as a carbon source
(c) organic molecules as energy sources and organic carbon as a carbon source
(d) inorganic molecules as electron sources and organic carbon as a carbon source
(e) inorganic molecules as energy sources and organic carbon as a carbon source.
INORGANIC MOLECULES AS ENERGY SOURCES AND INORGANIC CARBON AS A CARBON SOURCE
- For a carbon source, chemoorganotrophs generally use such compounds as
(a) glucose
(b) carbon dioxide
(c) triglycerides
(d) sodium nitrate
(e) hydrogen sulfide
GLUCOSE
- The most important high energy phosphate compound in living organisms is
(a) Glucose
(b) AMP
(c) RNA
(d) ATP
(e) Polyphosphate
ATP
- The enzyme-regulated energy-requiring reactions in a cell are involved mostly in
(a) catabolism
(b) anabolism
(c) photosynthesis
(d) oxidation
(e) reduction
ANABOLISM
- Enzymes increase the speed of a chemical reaction by
(a) lowering the energy of activation
(b) Increasing the energy of activation
(c) Increasing the frequency of collisions of the reactants
(d) Decreasing the frequency of collisions of the reactants
(e) None of the above
LOWERING THE ENERGY OF ACTIVATION
- In aerobic respiration, the terminal electron acceptor is:
(a) Hydrogen
(b) Oxygen
(c) Water
(d) ATP
(e) Sulfur
OXYGEN
- If an oxidation reaction occurs:
(a) Another oxidation reaction will occur for a complete reaction, because one oxidation
event is considered a half reaction
(b) A cell is undergoing aerobic respiration, because oxygen is being used
(c) Simultaneous reduction of a different compound will also occur, because electrons do not generally exist alone in solution
(d) A reduction reaction would not occur, because they are opposite reaction mechanisms
SIMULTANEOUS REDUCTION OF A DIFFERENT COMPOUND WILL ALSO OCCUR, BECAUSE ELECTRONS DO NOT GENERALLY EXIST ALONE IN SOLUTION
- The standard reduction potential of the first electron carrier in the electron transport chain is:
(a) The most positive
(b) The most negative
(c) Zero
(d) None of the above
THE MOST NEGATIVE
- When oxygen reacts with hydrogen gas, water is produced as the product in this
oxidation-reduction reaction. Hydrogen donates electrons to oxygen in the reaction.
Which statement below is true about this reaction?
(a) Oxygen is oxidized to water.
(b) Oxygen is being reduced in the reaction.
(c) Hydrogen is being reduced in the reaction.
(d) The electron donor in this reaction is reduced.
(e) The electron acceptor in this reaction is oxidized.
OXYGEN IS BEING REDUCED IN THE REACTION
- The purpose of the electron transport chain is to:
(a) Accumulate electrons to store energy
(b) Transfer electrons in order to generate ATP
(c) Donate electrons to change membrane potential
(d) Transport electrons to reductive biochemical pathways
(e) All of the above
TRANSFER ELECTRONS IN ORDER TO GENERATE ATP
- Where the electron transport chain is located in bacterial and archaeal cells:
(a) Cytoplasm
(b) Mitochondrial membranes
(c) Outer membrane
(d) Cytoplasmic membrane
CYTOPLASMIC MEMBRANE
- In which of the following is chemical energy used for carbon fixation?
(a) Chemosynthesis
(b) Krebs or TCA cycle
(c) Fermentation
(d) Glycolysis
(e) None of the above
CHEMOSYNTHESIS
- Oxidative phosphorylation uses all of the following for energy production except:
(a) electrons from NADH
(b) membrane-associated electron transport chain
(c) an ATP synthase
(d) Phosphoenolpyruvate
(e) a proton motive force
PHOSPHOENOLPYRUVATE
- Theoretically, the net gain of ATP per molecule of glucose metabolized in aerobic
respiration by bacteria is:
(a) 2
(b) 4
(c) 36
(d) 38
(e) none of the above
38
- Fermentation uses which of the following mechanisms for energy generation:
(a) Photophosphorylation
(b) Oxidative phosphorylation
(c) Substrate level phosphorylation
(d) Electron transport by the electron transport chain
(e) Chemiosmosis
SUBSTRATE LEVEL PHOSPHORYLATION
- Lactic acid is a common fermentation product. It is produced when ___________ is
reduced by electrons received from NADH.
(a) ethanol
(b) glucose
(c) pyruvate
(d) acetyl-CoA
(e) 3-phosphoglyceraldehyde
PYRUVATE
- A metabolic pathway that can completely catabolize an organic energy source to CO2
using the glycolytic pathways and TCA cycle with O2 as the terminal electron acceptor
for an ETC is called:
(a) Fermentation
(b) Chemolithotrophy
(c) Aerobic respiration
(d) Anaerobic respiration
(e) All of the above
AEROBIC RESPIRATION
- In cyclic photophosphorylation, the electrons:
(a) return to chlorophyll
(b) are incorporated in NADPH
(c) are converted to ATP
(d) are converted to glucose
(e) are taken up by oxygen
RETURN TO CHLOROPHYLL
- Which of the following can be used as terminal electron acceptors by chemolithotrophs?
(a) Oxygen
(b) Nitrate
(c) Ferric iron
(d) Sulfate
(e) All of the above
ALL OF THE ABOVE
- A fundamental difference between fermentation and respiration is:
(a) fermentation starts with sucrose and respiration starts with glucose.
(b) fermentation never uses oxygen as a terminal electron acceptor and respiration always
uses oxygen as a terminal electron acceptor.
(c) Fermentation bypasses the tca cycle and electron transport system and respiration includes the tca cycle and electron transport system.
(d) All of the above
FERMENTATION BYPASSES THE TCA CYCLE AND ELECTRON TRANSPORT SYSTEM AND RESPIRATION INCLUDES THE TCA CYCLE AND ELECTRON TRANSPORT SYSTEM
- Which of the following is a final product of a fermentative pathway?
(a) Propionate
(b) Pyruvate
(c) Glucose
(d) NADH
(e) Water
PROPIONATE
- For which group of microorganisms do many organic compounds serve as both a
source of energy and as a source of carbon building blocks of cellular material:
(a) Chemolithotrophs
(b) Chemoautotrophs
(c) Chemoheterotrophs
(d) Photoautotrophs
(e) Photoheterotrophs
CHEMOHETEROTROPHS
- Aerobic respiration differs from anaerobic respiration in all the following ways except:
(a) each pathway uses different electron acceptors
(b) each pathway uses different sources of electrons
(c) each pathway uses different electron carriers
(d) each pathway generates different amounts of ATP
EACH PATHWAY USES DIFFERENT ELECTRON ACCEPTORS
- The β-oxidation pathway is characterized by the:
(a) oxidation of polysaccharides joined by β linkages
(b) oxidation of proteins with a high percentage of β-pleated sheet secondary structure
(c) oxidation of amino acids to pyruvate to link with the TCA cycle
(d) Oxidation of highly reduced fatty acids
(e) None of the above
OXIDATION OF HIGHLY REDUCED FATTY ACIDS
- In ______________________ molecules other than water are used as an electron
source and no oxygen is produced
(a) Oxygenic photosynthesis
(b) Anoxygenic photosynthesis
(c) Aerobic respiration
(d) Oxidative phosphorylation
ANOXYGENIC PHOTOSYNTHESIS
- Many metabolic reactions in anaerobic environments are driven by methanogens
because of the rapid utilization of this material during methanogenesis.
(a) carbon dioxide
(b) sulfate
(c) formate
(d) hydrogen
(e) nitrogen
HYDROGEN
- Bacterial growth is defined as an increase in the:
(a) Size of individual cells
(b) Number of colonies present in a culture
(c) Number of individual cells
(d) Life span of the individual cells
(e) Diversity of cells
NUMBER OF INDIVIDUAL CELLS
- Most prokaryotic cellular reproduction is the result of:
(a) Conjugation
(b) Meiosis
(c) Mitosis
(d) Binary Fission
(e) Budding
BINARY FISSION
- When the population doubles during each given unit of time, the growth is said to be
(a) linear
(b) semilogarithmic
(c) exponential
(d) Cartesian
(e) turbid
EXPONENTIAL
- The time between inoculation and the beginning of growth is usually called the
(a) lag phase
(b) log phase
(c) dormant phase
(d) death phase
(e) growth phase
LAG PHASE
- In the death phase:
(a) The number of living cells declines exponentially
(b) Cells become viable but non-culturable (VBNC)
(c) Cells enter into a survival state
(d) Undergo programmed cell death
(e) All of the above can happen
THE NUMBER OF LIVING CELLS DECLINES EXPONENTIALLY
- An experiment began with 10 cells and ended with 160 cells. How many generations
did the cells go through?
(a) 16
(b) 8
(c) 5
(d) 4
(e) 3
4
- Generation time can best be defined as the
(a) length of time it takes for lag phase
(b) duration of log phase
(c) length of time it takes for a cell to divide
(d) minimum rate of doubling
LENGTH OF TIME IT TAKES FOR A CELL TO DIVIDE
- Bacteria grow in log phase for 12 generations in 4 hours. What is the generation time?
(a) 10 minutes
(b) 20 minutes
(c) 30 minutes
(d) 1 hour
(e) 4 hours
20 MINUTES
- Divisomes are responsible for:
(a) psychrotolerant growth
(b) osmotolerant growth
(c) thermostability at high temperatures
(d) septum formation in binary fission
(e) None of the above
SEPTUM FORAMTION IN BINARY FISSION
- Microorganisms that are sometimes found growing in brines, and salted foods like ham and
salted fish are known as what?
(a) Acidophiles
(b) Halophiles
(c) Neutrophiles
(d) Psychrophiles
(e) Barophiles
HALOPHILES
- Aseptic technique refers to the
(a) microbial inoculum placed into a test tube or onto a Petri plate
(b) autoclave and other sterilizing procedures
(c) prevention of contamination and spread of unwanted microbes
(d) cleanliness in the laboratory
(e) all of the above
PREVENTION OF CONTAMINATION AND SPREAD OF UNWANTED MICROBES
- A medium that inhibits growth of gram-positive bacteria is called:
(a) Defined
(b) Selective
(c) Complex
(d) Differential
(e) Selective and differential
SELECTIVE
- A laboratory protocol lists the following ingredients for growing heterotrophic bacteria:
5 g yeast extract, 10 g tryptone, 10 g NaCl, deionized water to 1 liter and autoclave.
This recipe is for a ________ medium.
(a) Defined agar
(b) Complex agar
(c) Defined broth
(d) Complex broth
(e) Enrichment broth
COMPLEX BROTH
- A microbe capable of growing in the presence of high concentrations of sugar is:
(a) Mesophilic
(b) Halophilic
(c) Psychrophilic
(d) Osmophilic
(e) Xerophilic
OSMOPHILIC
- A psychrophile is likely to grow best at
(a) 37°C
(b) 8°C
(c) 22°C
(d) 18°C
(e) 65°C
8°C
- A viable count:
(a) Is also called a direct count
(b) Is where all cells are counted
(c) Is where only living cells are counted
(d) Can only be done using agar plates
(e) Uses turbidity of a culture to estimate cell numbers
IS WHERE ONLY LIVING CELLS ARE COUNTED
- Choose the true statement. Bacterial colony counting is
(a) useful for enumerating bacteria found in clumps
(b) done by direct microscopic counts
(c) comprised of sample serial dilution and pour or spread agar plates
(d) done by determining turbidity measurements
(e) comprised of sample filtration and pour or spread agar plates
COMPRISED OF SAMPLE SERIAL DILUTION AND POUR OR SPREAD AGAR PLATES
- Blood agar is often used to differentiate between:
(a) salt sensitive and non-salt sensitive microbes
(b) bacteria that absorb oxygen and those that do not
(c) types of haemolysis the bacteria may produce
(d) all of the above
TYPES OF HAEMOLYSIS THE BACTERIA MAY PRODUCE
- The majority of medically significant microorganisms are
(a) thermophiles
(b) mesophiles
(c) psychrophiles
(d) halophiles
(e) xerophiles
MESOPHILES
