Microbiology Exam 2 (Ch. 4-6)
Pyruvic acid is metabolized in the absence of oxygen during the process of: a) glycolysis b) fermentation c) oxidation d) dark reactions
B
Starch would be broken down to maltose by which of the following exoenzymes? a) gelatinase b) amylase c) caseinase d) lipase
B
A culture that contains only a single species of organism is known as a _____. a) pure culture b) Koch culture c) mixed culture d) contaminated culture
A
A growth medium consisting of only known amounts of water, magnesium, calcium chloride, potassium and glucose would be considered: a) a defined synthetic medium b) a complex medium c) a chemically nondefined medium d) two of the above
A
A surfactant: a) lowers the surface tension at the bacterium's posterior end allowing Myxococcus to glide b) is metabolized to produce phosphoenolpyruvate c) forms channels thorugh the outer membrane d) emits light as it returns to its unexcited state
A
Bacterial growth in colonies on agar plates _____. a) have all phases of growth occurring simultaneously somewhere in the colony b) most growth occurs at the center of the colony c) involves budding of small new colonies from the surface of an existing colony d) have lag phase cells in the center of the colony, surrounded by a ring of cells in exponential phase
A
Bacterial ribosomes: a) have a sedimentation rate of 70S b) are made up of 30S and 40S subunits c) have a sedimentation rate of 80S d) are made up of 50S and 30S subunits
A
Capnophiles grow best under conditions of _____. a) high carbon dioxide b) low carbon dioxide c) high osmotic pressure d) low osmotic pressure
A
Chocolate agar: a) contains blood b) is used exclusively for stock cultures c) is nutrient poor d) is a selective agar plate
A
Competitive inhibition of enzymes occurs when the inhibitor: a) binds to the active site of the enzyme. b) binds to the allosteric site of the enzyme. c) inhibitor changes the shape of the enzyme. d) inhibitor is acted upon by the enzyme.
A
During glycolysis, electrons are initially transferred to: a) NAD+ b) FAD c) NADP d) H2O
A
Osmosis most directly involves: a) water moving down a concentration gradient b) organic molecules crossing a membrane c) energy being expended to import large molecules into the cell d) sugars and salts moving down their concentration gradient
A
Photoautotrophs obtain energy from: a) light and use carbon dioxide as a carbon source b) organic molecules and use carbon dioxide as a carbon source c) inorganic substances and use carbon dioxide as a carbon source d) light and use organic substances as a carbon source
A
Removal of the cell wall of a Gram positive bacteria results in the formation of a _____. a) protoplast b) spheroplast c) periplast d) polyplast
A
Sabourard's agar has a low pH which encourages the growth of molds and discourages the growth of bacteria. Sabourard's agar could best be described as being: a) selective b) differential c) complex d) enriched
A
Some bacteria can transfer DNA to another cell using: a) conjugation pili b) fimbriae c) axial filaments d) lophotrichous flagella
A
Sporulation occurs in: a) Clostridium b) Staphylocoocus c) Klebsiella d) Citrobacter
A
Sporulation usually occurs in response to a/an _____. a) decrease in the level of carbon or nitrogen b) increase in temperature c) decrease in the amount of water d) increase in ultraviolet radiation
A
The green sulfur and purple sulfur bacteria are capable of: a) carrying out photosynthesis b) only obtaining energy from organic molecules c) bypassing glycolysis for the Krebs cycle d) metabolizing without enzymes
A
The initial breakdown of glucose in a eukaryotic cell takes place in the _____. a) cytoplasm b) golgi c) nucleus d) cell membranes
A
The streak plate method produces pure cultures by separating individual bacterial cells from one another by _____. a) dragging them across a solid surface b) dispersing them in liquid media c) killing off those cells that are not able to survive in hot agar d) embedding some cells in the agar so that they are exposed to lower concentrations of oxygen
A
When a bacterial cell divides into two new cells, the new cells are called: a) daughter cells b) sister cells c) son cells d) father cells
A
Which of the following is true about bacteria? a) All bacteria cells are smaller than 100 micrometers in diameter. b) The cell wall controls the movement of small molecules into and out of the cell. c) Gram negative bacteria become protoplasts when their cell wall is digested away. d) Bacterial endospores are reproductive structures.
A
Which of the following statements about outer membranes is true? a) It contains an endotoxin (lipopolysaccharide) which is responsible for fever and potentially serious complications in human infections. b) It prevents the cell from lysing when fluids flow into the cell. c) Treatment with antibiotics which kill the bacteria will reduce the concentration of endotoxin. d) It is a space that is very active in cell metabolism
A
Within a bacterial endospore, the spore is most closely surrounded by the _____. a) spore membrane b) cortex c) cell membrane d) spore coat
A
_____ occurs when bacteria differ widely in form. a) Pleomorphism b) Polymorphism c) Anamorphism d) Telomorphism
A
A bacterial population grows most rapidly during ________ phase. a) lag b) log c) stationary d) death
B
A growth medium consisting of only water, glucose and beef extract would be considered _____. a) a defined synthetic medium b) a complex medium c) a chemically defined medium d) two of the above
B
A living, growing culture whose purpose is to maintain a pure culture of an organism indefinitely is a _____. a) colony b) stock culture c) sporulating culture d) broth culture
B
A media on which Gram positive organism turn green and Gram negative organisms turn blue would be _____. a) selective b) differential c) complex d) enriched
B
A metabolic pathway that is involved in both breakdown and synthetic reactions is properly termed _____. a) catabolic b) amphibolic c) metabolic d) anabolic
B
All of the following are electron acceptors for anaerobic respiration, except: a) carbon dioxide b) oxygen c) nitrate ions d) sulfate ions
B
Bacteria move by means of: a) cilia b) flagella c) fimbriae d) pili
B
Bacteria that ferment lactose grow as red colonies on MacConkey's agar while those that do not ferment lactose are transparent. MacConkey's agar can best be described as being: a) selective b) differential c) complex d) enriched
B
Bacteria with flagella all over their surface are said to be: a) monotrichous b) peritrichous c) amphitrichous d) lophotrichous
B
Degradation reactions where large molecules are broken down into smaller molecule is referred to as: a) metabolism b) catabolism c) biosynthesis d) anabolism
B
During diffusion, molecules _____. a) move from hotter areas to cooler areas b) move from areas of higher concentration to areas of lower concentration c) move from areas of lower concentration to areas of higher concentration d) expend energy to more around
B
During the metabolism of fats, the product of beta-oxidation enters: a) glycolysis b) Krebs cycle c) oxidative phosphorylation d) electron transport chain
B
Endocytosis: a) releases material in the form of phagosomes. b) is the process of taking materials into the cell. c) directs material to the endoplasmic reticulum. d) uses simple diffusion move material across the plasma membrane.
B
Endospores are typically found in the genus: a) Streptococcus b) Clostridium c) Mycobacterium d) Staphylococci
B
Endospores are usually induced to form when: a) temperatures rise b) certain nutrient are depleted c) radiation is detected d) water is lost from the cell
B
Extrachromosomal DNA in prokaryotic cells can be found in the form of _____. a) chromosomes b) plasmids c) mitochondria d) chloroplasts
B
In aerobic respiration, the final electron acceptor is: a) water b) oxygen c) sulfur d) coenzyme Q
B
In glycolysis, each molecule of glucose eventually produces ________ molecules of pyruvic acid. a) one b) two c) three d) four
B
In photosynthesis, chemical energy is used to make organic molecules in the: a) light reaction b) dark reaction c) hydrolytic reaction d) photophosphorylation reaction
B
Microaerophiles: a) grow best when the environment has a small amount of carbon dioxide. b) grow best when the environment has a small amount of free oxygen. c) need a high concentration of carbon dioxide. d) need a high concentration of oxygen.
B
Most bacteria reproduce by: a) sexual reproduction b) binary fission c) budding d) homologous recombination
B
Most human pathogens are _____. a) psychrophiles b) mesophiles c) thermophiles d) acidophiles
B
Nonculturable organisms: a) are rare. b) can be identified based on their DNA. c) can only be seen on selective agar plates. d) have defined generation times.
B
Organisms with special nutritional needs are said to be _____. a) barophiles b) fastidious c) aerobes d) none of the above
B
Peptidoglycan makes up more than 50% of a ________ cell wall. a) Gram negative b) Gram positive c) Gram variable d) acid-fast
B
Prokaryotic cells divide by _____. a) mitosis b) binary fission c) meiosis d) mitosis asexually and meiosis sexually
B
Substrate level phosphorylation during glycolysis refers to the transfer of phosphate groups from: a) ATP to glucose b) 1,3 diphosphoglyceric acid to ADP c) phosphoenolpyruvic acid to ADP d) ATP to ADP
B
Sulfa drugs bind to the active site of the enzyme which normally converts para-amino benzoic acid (PABA) to folic acid, preventing the production of folic acid and, eventually purine synthesis. In this case, the sulfa drug is acting as a/an: a) allosteric inhibitor b) competitive inhibitor c) noncompetitive inhibitor d) uncompetitive inhibitor
B
The Fluid-mosaic model describes the structure of _____. a) cell walls b) cell membranes d) capsules d) endosymbiotic relationships
B
The _____ portion of the cell membrane functions as a barrier while the ______ portion provides specific functions, including pumps, receptors, adhesion, etc. a) carbohydrate; nucleic acid b) lipid; protein c) lipid; carbohydrate d) nucleic acid; lipid
B
The charged, phosphate end of a membrane phospholipid is: a) water-fearing b) hydrophilic c) hydrophobic d) none of the above
B
The initial substrate molecule for the Krebs cycle is: a) pyruvic acid b) acetyl-CoA c) acetic acid d) butanediol
B
The shape of a bacterial cell is determined (and maintained) by the _____. a) cell membrane b) cell wall c) capsule d) slime layer
B
The synthesis of DNA, in which small nucleotides are joined together to make a single large molecule would be most correctly described as being a/n ________ reaction. a) metabolic b) anabolic c) catabolic d) cytobolic
B
What is the function of gas-filled vacuoles in aquatic photosynthetic bacteria? a) transducers to detect chemicals and signal the cells to respond b) regulate the depth at which they float by changing amount of gas in vacuoles c) change the handedness of the helix in which the bacteria is moving d) allows the bacteria to respond to magnetic fields
B
Which of the following is responsible for converting sunlight into chemical energy? a) Chromatophores b) Chloroplasts c) Endoplasmic reticulum d) Two of the above
B
Which of the following statements about bacterial growth is false? a) Agar is used as a solidifying agent in some types of media. b) Bacteria growing in a liquid culture will generate colonies. c) A turbid culture is indicative of bacterial growth. d) Each bacterium plated will represent a colony-forming unit.
B
Which type of cell will generally shift to aerobic metabolism when oxygen is available but will carry on fermentation otherwise? a) aerotolerant anaerobes b) facultative anaerobes c) obligate anaerobes d) obligate aerobes
B
A decrease in the amount of nitrogen to a culture of Clostridium botulinum would induce _____. a) activation b) germination c) sporulation d) outgrowth
C
Coccus-shaped cells which divide along two planes will produce cells arranged into _____. a) diplococci b) streptococci c) tetrads d) staphylococci
C
Enzymes work by: a) lowering the energy of the reactants. b) raising the energy of the products. c) decreasing the activation energy of the reaction. d) increasing the activation energy of the reaction.
C
Halophiles require an environment with a high concentration of ________ for optimal growth. a) sugar b) alcohol c) salt d) phosphorous
C
In algae, the dark reactions of photosynthesis occur in the: a) cell membrane b) matrix of the mitochondria c) stroma of the chloroplast d) nucleus
C
In bacteria, the cell membrane functions in the all of the following ways except: a) regulate movement of materials into and out of the cell b) synthesizes cell wall components c) serve as the site for protein synthesis d) assists with DNA replication
C
In the electron transport chain, the energy to make ATP comes directly from _____. a) FAD b) NADH c) both FAD and NADH d) neither FAD nor NADH
C
In the stationary phase of bacterial growth: a) the number of newly generated cells is greater than the number of dying cells b) the number of newly generated cells is less than the number of dying cells c) the number of newly generated cells is the same as the number of dying cells d) none of the above
C
Lysozyme, found in human tears, controls the growth of bacteria by _____. a) fusing with vacuoles b) containing multiple kinds of digestive enzymes c) digesting peptidoglycan d) preventing peptidoglycan synthesis
C
Mitochondria: a) are responsible for converting sunlight to chemical energy b) are present only in photosynthetic organisms c) have a double membrane d) are responsible for protein synthesis
C
Most bacteria: a) exhibit synchronous growth under natural conditions b) divide when a small new cell develops from the surface of an existing cell c) do not immediately increase in number when placed in a culture d) immediately begin to divide when placed in a culture
C
Oxidation is defined as the ________ while reduction is the ________ . a) gain of electrons, loss of protons b) loss of electrons, gain of protons c) loss of electrons, gain of electrons d) loss of protons, gain of protons
C
Serial dilutions are used to: a) slow down the growth of microbes b) speed up the growth of microbes c) obtain bacterial cultures at several different concentrations d) form bacterial colonies
C
The cytoskeleton consists of _____. a) microfilaments and sterols b) microtubules and proteins c) microfilaments and microtubules d) sterols and proteins
C
The first step in protein metabolism is the breakdown of proteins into: a) nucleotides b) fatty acids c) amino acids d) coenzymes
C
The most important structural component of bacterial cell walls is _____. a) teichoic acid b) lipotechoic acid c) peptidoglycan d) glutamic acid
C
The outer (cell) membrane component of the cell wall _____. a) is found only in Gram positive bacteria b) is made primarily of peptidoglycan c) contains lipopolysaccharrides d) is primarily a reproductive structure
C
The rough endoplasmic reticulum appears rough because of _____. a) sterols in its membrane b) fats and sugars on its surface c) multiple ribosomes on its surface d) proteins in the lumen of the ER
C
Turbidity in a bacterial culture can be measured using a/an: a) incubator b) colony county c) spectrophotometer d) chemostat
C
Which bacterial genus normally lacks a cell wall? a) Mycobacterium b) Streptococcus c) Mycoplasma d) Bacillus
C
Which of the following statements about enzyme inhibition is true? a) Most noncompetitive inhibitors bind to several different sites on an enzyme. b) Enzymes become less efficient as temperatures drop because they begin to denature. c) Noncompetitive inhibitors bind to a site other than the active site. d) Most human enzymes have an optimum temperature below normal body temperature.
C
Which statement is true about enzymes? a) Enzyme catalyzed reactions would not go forward without their specific enzymes. b) Most enzymes catalyze several different reactions. c) Coenzymes are organic molecules while cofactors are inorganic molecules. d) An apoenzyme is a holoenzyme that is missing its cofactor.
C
A candle jar would be used for growing: a) Gram negative organisms b) fastidious organisms c) thermophiles d) microaerophiles
D
A charged molecule which moves down its concentration gradient and across a pore in a cell membrane without energy being expended by the cell is experiencing _____. a) simple diffusion b) osmosis c) active transport d) facilitated diffusion
D
A holoenzyme consists of: a) an apoenzyme plus a cofactor b) an apoenzyme plus a coenzyme c) an protein and non-protein component d) all of the above
D
An enzyme-substrate complex forms when substrate binds to an enzyme at the enzyme's ______ site. a) catalytic b) allosteric c) operative d) active
D
Animals (humans for example) are: a) photoautotrophs b) photheterotrophs c) chemoautotrophs d) chemoheterotrophs
D
Attachment pili do all of the following except, a) help bacteria adhere to surfaces b) allow bacteria to form a pellicle at the air-water interface of a broth culture c) clump blood cells in a process called hemagglutination d) prevent the pathogenicity of certain bacteria
D
Bacilli produce fewer arrangements than cocci because _____. a) cocci are smaller than bacilli b) bacilli only reproduce asexually c) bacilli divide along several different planes while cocci divide along a single plane d) cocci divide along several different planes while bacilli divide along a single plane
D
Chemiosmosis: a) forms ATP b) occurs in the cell membrane of prokaryotes c) uses a proton gradient to activate ATP synthase d) all the above
D
Chemoautotrophic bacteria obtain the energy they need from: a) the reactions of photosynthesis b) sunlight c) carbon dioxide in the atmosphere d) chemical reactions in their cytoplasm centered around the use of inorganic substances
D
Endospores are: a) metabolically active b) reproductive structures c) found mostly in Gram negative organisms d) protective structures
D
Eukaryotic cells add rigidity to their plasma membrane by including what component in the membrane? a) Protein b) Lipids c) Sugars d) Sterols
D
Factors that affect the rate of enzyme catalyzed reactions include: a) temperature b) pH c) concentration of enzyme d) all of the above
D
Genetic information in bacteria is: a) found in the nucleus b) found only in RNA c) found in DNA condensed by histones d) sometimes found in the form of plasmids
D
In fermentation reactions occurring in yeast to produce wine, two products of the reaction are __________ and _________. a) acid; hydrogen gas b) hydrogen gas; propionic acid c) ethyl alcohol; methane d) carbon dioxide; ethyl alcohol
D
Microbial growth: a) refers to the increase in the size of a microbial cell b) refers to the increase in the frequency of cell division c) in a single generation time leads to double the cell size d) in a single generation time leads to double the number of microbes.
D
Mycolic acid would be found primarily in the cell wall of: a) Gram positive bacteria b) Gram negative bacteria c) Gram variable bacteria d) acid-fast bacteria
D
Organisms that can use oxygen for metabolic reactions but can also function in an environment devoid of oxygen are termed _____. a) aerobes b) anaerobes c) aerophiles d) facultative anaerobes
D
Organisms which get their carbon from other organisms are: a) autotrophs b) chemotrophs c) phototrophs d) heterotrophs
D
Penicillin controls the growth of bacteria by _____. a) destroying cell membranes b) preventing protein synthesis c) removing cell walls d) preventing peptidoglycan synthesis
D
The electrons transferred from acetyl groups in the Krebs cycle are transferred to: a) NAD+ only b) FAD only c) neither NAD+ and FAD d) both NAD+ and FAD
D
The end product of glycolysis is: a) fructose-1,6-diphosphate b) 1,3 diphosphoglyceric acid c) phosphoenolpyruvic acid d) pyruvic acid
D
The periplasmic space is found _____. a) only in Gram positive organisms b) between the nuclear area and the cell membrane c) primarily in acid fast bacteria d) between the innercell membrane and outer cell wall membrane
D
The pour plate method of isolating pure cultures _____. a) relies on the fact that liquid agar will solidify as it cools b) is useful for growing microaerophiles c) results in some organisms growing embedded in the agar d) all of the above
D
The type of cell reproduction in which a small, new cell develops from the surface of an existing cell and then separates from the parent cell is known as ________ and is the normal mode of replication in _____ . a) binary fission, bacteria b) binary fission, yeast c) budding, bacteria d) budding, yeast
D
When cells are placed in a hypertonic environment they will undergo ________ . a) lysis b) no change in size c) swelling of the cell which is contained by the cell wall d) plasmolysis
D
When the fluid within a cell has a higher concentration of dissolved substances than the fluid surrounding the cell, we say the fluid surrounding the cell is _____. a) hypertonic b) isotonic c) superhypertonic d) hypotonic
D
Which of the following is not found in bacterial cells? a) A cell membrane, usually surrounded by a cell wall b) An internal cytoplasm with ribosomes, a nuclear region and in some cases granules c) A variety of external structures, such as capsules, flagella and pili d) Respiratory enzymes contained in an internal structure surrounded by membranes
D
_____ techniques must be strictly adhered to prevent the accidental contamination of stock cultures. a) Germination b) Selective c) Differential d) Aseptic
D