Superantigens produce intense immune responses by stimulating lymphocytes to produce ___.

Superantigens produce intense immune responses by stimulating lymphocytes to produce ___.

A. endotoxins
B. exotoxins
C. cytokines
D. leukocidins
E. interferons


Answer: C. cytokines

Competent cells are cells that _____.

Competent cells are cells that _____.

A. can take up DNA from their surrounding environment and integrate it into their own chromosomes by recombination
B. are killed by heat
C. are also considered "rough-strain" based on colony phenotype
D. have the ability to produce capsules


Answer: A. can take up DNA from their surrounding environment and integrate it into their own chromosomes by recombination

Hfr cells arise when _____.

Hfr cells arise when _____.

A. they have multiple F plasmids
B. a cell's F plasmid has been incorporated into the bacterial chromosome
C. conjugation and transformation happen at the same time
D. bacterial chromosomes do not break during conjugation


Answer: B. a cell's F plasmid has been incorporated into the bacterial chromosome

A gene is best defined as ______.

A gene is best defined as ______.

A. a segment of DNA
B. three nucleotides that code for an amino acid
C. a segment of DNA that codes for a functional product
D. a segment of RNA that codes for a functional product


Answer: C. a segment of DNA that codes for a functional product

tRNA molecules serve as a link between ______.

tRNA molecules serve as a link between ______.

A. DNA and mRNA
B. codons and anticodons
C. codons and amino acids
D. mRNA and rRNA


Answer: C. codons and amino acids

Two daughter cells are most likely to inherit which one of the following from the parent cell?

Two daughter cells are most likely to inherit which one of the following from the parent cell?

A. A change in a nucleotide in mRNA.
B. A change in a nucleotide in tRNA.
C. A change in a nucleotide in rRNA.
D. A change in a nucleotide in DNA.
E. A change in a protein.


Answer: D. A change in a nucleotide in DNA.

Which of these is a mutation?

Which of these is a mutation?

A. A change in the gene that codes for the Lactase enzyme.
B. An error in translation that produces a Lactase enzyme that can also bind to sucrose.
C. Damage to the mRNA molecule that codes for the Lactase enzyme.
D. A transfer of the lactase gene from one cell to another.


Answer: A. A change in the gene that codes for the Lactase enzyme.

A bacterium has received new DNA that does not give it a new ability. Which of the following statements is true?

A bacterium has received new DNA that does not give it a new ability. Which of the following statements is true?

A. There is a change in both the genotype and phenotype.
B. There is a change in the genotype, not the phenotype.
C. There is a change in the phenotype, not the genotype.
D. There is no change in either the genotype or the phenotype.


Answer: B. There is a change in the genotype, not the phenotype.

Which of the following would most likely result in a frameshift mutation?

Which of the following would most likely result in a frameshift mutation?

A. An adenine is inserted into the DNA sequence of an organism
B. A thymine is replaced by a guanine in the DNA sequence of a organism.
C. Three new bases are inserted into the DNA strand
D. Three new bases are deleted from the DNA strand


Answer: A. An adenine is inserted into the DNA sequence of an organism

What is the function of the Parental DNA in replication?

What is the function of the Parental DNA in replication?

A. It is passed into the offspring of the parent.
B. It allows for the DNA to be circular.
C. it gives the cell two complete copies of the DNA.
D. It serves as the template for DNA replication.


Answer: D. It serves as the template for DNA replication.

Which of these is characteristic of nonionizing radiation with respect to the DNA damage?

Which of these is characteristic of nonionizing radiation with respect to the DNA damage?

A. Cause structural damage
B. Causes mismatched base pairing due to structural similarities with nitrogenous bases
C. Causes abnormal base pairing due to thymine dimer formation
D. Causes deletions by breaking covalent bonds in DNA


Answer: C. Causes abnormal base pairing due to thymine dimer formation

Which type of plasmid is most likely to carry the gene for an enzyme that can metabolize the sugar arabinose?

Which type of plasmid is most likely to carry the gene for an enzyme that can metabolize the sugar arabinose?

A. F plasmid
B. R plasmid
C. A dissimulation plasmid
D. An integration plasmid


Answer: C. A dissimulation plasmid

Which of these types of mutations is potentially the least damaging?

Which of these types of mutations is potentially the least damaging?

A. Silent mutations
B. Missense mutations
C.Nonsense mutations


Answer: A. Silent mutations

DNA replication is _____.

DNA replication is _____.

A. Semi conservative
B. Conservative
C. Dispersive
D. Conservative on the lagging strand


Answer: A. Semi conservative

Cells able to accept naked DNA from the surrounding area are said to be ____.

Cells able to accept naked DNA from the surrounding area are said to be ____.

A. Transduction ready
B. Capable
C. Competent
D. Transformable


Answer: C. Competent

Which of the following is not a method of horizontal gene transfer?

Which of the following is not a method of horizontal gene transfer?

A. Binary Fission
B. Conjugation
C. Transfer of DNA via a bacteriophage infection
D. Uptake of DNA from the environment


Answer: A. Binary Fission

Which of the following pairs is mismatched?

Which of the following pairs is mismatched?

A. DNA polymerase-makes a molecule of DNA from a DNA template
B. RNA polymerase-makes a molecule of DNA from an RNA template
C. Helicase-unwinds double stranded DNA
D. Genome-all the DNA in an organism


Answer: B. RNA polymerase-makes a molecule of DNA from an RNA template

During which process do most mutations occur?

During which process do most mutations occur?

A. DNA replication
B. Transcription
C. Translation
D. Transduction


Answer: A. DNA replication

An enzyme that covalently bonds nucleotides together is _____.

An enzyme that covalently bonds nucleotides together is _____.

A. DNA polymerase
B. RNA polymerase
C. The ribosome
D. Both DNA and RNA polymerase


Answer: D. Both DNA and RNA polymerase

When discussing a microbe's ability to resist an antibiotic, you are talking about the organism's ______.

When discussing a microbe's ability to resist an antibiotic, you are talking about the organism's ______.

A. Genotype
B. Phenotype


Answer: B. Phenotype

A sequence of DNA nucleotides which provides genetic information for a functional product is a _____.

A sequence of DNA nucleotides which provides genetic information for a functional product is a _____.

A. Chromosome
B. Plasmid
C. Gene
D. Base pair


Answer: C. Gene

What must occur for bacterial conjugation to take place?

What must occur for bacterial conjugation to take place?

A. Each cell must contain a plasmid.
B. The cells must come into contact with each other.
C. The cells must transfer RNA
D. One of the cells must be E. coli.


Answer: B. The cells must come into contact with each other.

Nucleoside analogs can cause mutations by _____.

Nucleoside analogs can cause mutations by _____.

A. Interfering with normal pairing of bases
B. Causing structural damage to DNA
C. Forming covalent bonds in a DNA molecule
D. Creating deletions in a DNA molecule


Answer: A. Interfering with normal pairing of bases

Which enzyme is responsible for unzipping the double-stranded DNA?

Which enzyme is responsible for unzipping the double-stranded DNA?

A. DNA polymerase
B. DNA helicase
C. DNA ligase
D. DNA zippase
E. DNA unzippase


Answer: B. DNA helicase

The drug chloramphenicol binds to the 50S ribosomal subunit of bacteria. From this information you can conclude that chloramphenicol _____.

The drug chloramphenicol binds to the 50S ribosomal subunit of bacteria. From this information you can conclude that chloramphenicol _____.

A. Prevents transcription
B. Prevents translation
C. Prevents DNA replication
D. Prevents cellular respiration


Answer: B. Prevents translation

An enzyme that copies DNA to make a molecule of RNA is ____.

An enzyme that copies DNA to make a molecule of RNA is ____.

A. RNA polymerase
B. DNA ligase
C. Transposes
D. DNA polymerase


Answer: A. RNA polymerase

A cell that cannot make tRNA _____.

A cell that cannot make tRNA _____.

A. can make proteins if amino acids are provided in the growth medium.
B. can make proteins if mRNA is provided in the growth medium
C. can't make proteins unless lipids are provided in the growth medium
D. can't make proteins
E. can't copy its DNA


Answer: D. can't make proteins

Which of the following statements regarding genomes is true?

Which of the following statements regarding genomes is true?

A. Plasmids are not considered part of the genome because they are not a part of the chromosome.
B. Plasmids are a part of the chromosome, so they are considered a part of the genome.
C. The genome includes all the DNA in a cell, including plasmids.
D. The genome includes all the DNA, including plasmids, and RNA in a cell


Answer: C. The genome includes all the DNA in a cell, including plasmids.

DNA replication is the synthesis of DNA from a _____ template.

DNA replication is the synthesis of DNA from a _____ template.

A. DNA
B. RNA
C. protein


Answer: A. DNA

Which of the following is not true of a bacterium that is R+?

Which of the following is not true of a bacterium that is R+?

A. R+ refers to the possession of a plasmid.
B. R+ can be transferred to a recipient cell.
C. It is resistant to certain drugs.
D. It is F+.


Answer: D. It is F+.

What are the products of semiconservative replication for a double-stranded DNA molecule?

What are the products of semiconservative replication for a double-stranded DNA molecule?

A. Two double-stranded DNA molecules, one consisting of two parental strands and the other consisting of two daughter strands.
B. One double-stranded DNA molecule, consisting of two daughter strands.
C. Two double-stranded DNA molecules, each consisting of one parental strand and one daughter strand.
D. One double-stranded DNA molecule consisting of one parental strand and one daughter strand.


Answer: C. Two double-stranded DNA molecules, each consisting of one parental strand and one daughter strand.

Which of the following properties are exclusive (unique) to tRNA?

Which of the following properties are exclusive (unique) to tRNA?

A. Combines with specific proteins to form ribosomes.
B. carries information from DNA for synthesis of a protein.
C. Molecules contain an anticodon.
D. Contains the nucleotide thymine.


Answer: C. Molecules contain an anticodon.

Which of the following properties are exclusive (unique) to mRNA?

Which of the following properties are exclusive (unique) to mRNA?

A. Combines with specific proteins to form ribosomes.
B. carries information from DNA for synthesis of a protein.
C. Molecules contain an anticodon.
D. Contains the nucleotide thymine.


Answer: B. carries information from DNA for synthesis of a protein.

____ refers to the specific characteristics displayed by an organism.

____ refers to the specific characteristics displayed by an organism.

A. Genotype
B. Mutation
C. Phenotype
D. Genes


Answer: C. Phenotype

Which of the following properties are exclusive (unique) to rRNA?

Which of the following properties are exclusive (unique) to rRNA?

A. Combines with specific proteins to form ribosomes.
B. Carries information from DNA for synthesis of a protein.
C. Molecules contain an anticodon.
D. Contains the nucleotide thymine.


Answer: A. Combines with specific proteins to form ribosomes.

The genetic information needed for a F+ cell to participate in conjugation can be found in the DNA of a cell's ____.

The genetic information needed for a F+ cell to participate in conjugation can be found in the DNA of a cell's ____.

A. chromosome
B. F factor
C. F pilus
D. mitochondria


Answer: B. F factor

A bacterium has received new DNA that allows it to produce a toxin. Which of the following statements is true?

A bacterium has received new DNA that allows it to produce a toxin. Which of the following statements is true?

A. There is a change in both the genotype and phenotype.
B. There is a change in the genotype, not the phenotype.
C. There is a change in the phenotype, not the genotype.
D. There is no change in either the genotype or the phenotype.


Answer: A. There is a change in both the genotype and phenotype.

Bacteria which show a variety of shapes within a single species are said to be ______.

Bacteria which show a variety of shapes within a single species are said to be ______.

A. Pleomorphic
B. Axenic
C. Monomorphic
D. Manymorphic


Answer: A. Pleomorphic

If you isolate LPS from the cell wall of an unknown microbe, you know that _________.

If you isolate LPS from the cell wall of an unknown microbe, you know that _________.

A. You have isolated a virus.
B. You have isolated an archaea.
C. The cell wall is composed of cellulose.
D. You have isolated a gram-negative bacterium.
E. You have found a fungus.


Answer: D. You have isolated a gram-negative bacterium.

Why is no energy required in passive transport?

Why is no energy required in passive transport?

A. The membrane physically moves the molecules.
B. The concentration gradient drives the movement.
C. Transport proteins move the molecules, so no energy is required.


Answer: B. The concentration gradient drives the movement.

How would a cell without flagella be described?

How would a cell without flagella be described?

A. Monotrichous
B. Nontrichous
C. Pseudotrichous
D. Atrichous
E. Peritrichous


Answer: D. Atrichous

Fimbriae and pili differ in that pili ______.

Fimbriae and pili differ in that pili ______.

A. Are used to transfer DNA.
B. Are composed of pilin.
C. Are used for asexual reproduction.
D. Are composed of flagellin.
E. Are used to survive harsh environments.


Answer: A. Are used to transfer DNA.

Which organelle is used to produce sugars from carbon dioxide and sunlight?

Which organelle is used to produce sugars from carbon dioxide and sunlight?

A. Mitochondria
B. Chloroplasts
C. Lysosomes
D. Endoplasmic reticulum
E. Ribosomes


Answer: B. Chloroplasts

Which structure can protect bacteria from being phagocytized?

Which structure can protect bacteria from being phagocytized?

A. Slime layer
B. Fimbriae
C. Capsule
D. Cell membrane
E. Cell wall


Answer: C. Capsule

Cells placed in a hypotonic solution tend to lose water due to osmotic pressure.

Cells placed in a hypotonic solution tend to lose water due to osmotic pressure.

A. True
B. False


Answer: B. False

Which of these organelles are found in algae, but not fungi?

Which of these organelles are found in algae, but not fungi?

A. Mitochondria
B. Chloroplasts
C. Ribosomes
D. ER
E. Lysosomes


Answer: B. Chloroplasts

Even though narrow spectrum antibiotics are only effective against a few species, they are preferred because ______.

Even though narrow spectrum antibiotics are only effective against a few species, they are preferred because ______.

A. They can kill microbes faster.
B. Broad spectrum antibiotics are often toxic to humans.
C. They are never toxic to humans.
D. Broad spectrum antibiotics will kill the normal microbiota as well.
E. The protection they provide lasts longer.


Answer: D. Broad spectrum antibiotics will kill the normal microbiota as well.

Which of the following cell structures has a role in the initiation of disease?

Which of the following cell structures has a role in the initiation of disease?

A. Cell membrane
B. Fimbriae
C. Flagella
D. Gram-positive cell wall
E. Ribosomes


Answer: B. Fimbriae

If a eukaryotic cell lost its peroxisomes, it would _____.

If a eukaryotic cell lost its peroxisomes, it would _____.

A. Lose the ability to generate cell energy.
B. Lose the ability to digest solid waste.
C. Lose the ability to synthesize lipids.
D. Lose the ability to break down alcohol, a toxin.
E. Lose the ability to photosynthesize.


Answer: D. Lose the ability to break down alcohol, a toxin.

If you isolate teichoic acid from the cell wall of an unknown microbe, you know that _________.

If you isolate teichoic acid from the cell wall of an unknown microbe, you know that _________.

A. You have isolated a eukaryotic cell.
B. You have isolated gram-negative bacterium.
C. The cell wall is composed of cellulose.
D. You have isolated a gram-positive bacterium.


Answer: D. You have isolated a gram-positive bacterium.

Which of the following molecules can freely cross the plasma membrane?

Which of the following molecules can freely cross the plasma membrane?

A. H2
B. 1O2-
C. A nucleotide
D. Sucrose



Answer: B. 1O2-

What is the function of the ER?

What is the function of the ER?

A. Synthesize molecules
B. Breakdown toxins
C. Transport molecules
D. Stores excess energy reserves.
E. Generate ATP


Answer: A. Synthesize molecules

In a hypotonic solution, a Gram-positive bacterial cell will typically ______.

In a hypotonic solution, a Gram-positive bacterial cell will typically ______.

A. Shrink
B. Burst
C. Stay the same
D. Plasmolyze
E. Osmolyze


Answer: E. Osmolyze

By which of the following mechanisms can a cell transport a substance from a lower concentration to a higher concentration?

By which of the following mechanisms can a cell transport a substance from a lower concentration to a higher concentration?

A. Simple diffusion
B. Facilitated diffusion
C. Active transport
D. Osmosis
E. Aquaporins


Answer: C. Active transport

Some microbes can cause secondary infections after being killed by antibiotics due to the release of an LPS endotoxin. Which of these microbes could cause such an infection?

Some microbes can cause secondary infections after being killed by antibiotics due to the release of an LPS endotoxin. Which of these microbes could cause such an infection?

A. Staphylococcus aureus, a gram positive microbe found on your skin.
B. Plasmodium vivax, a protozoan parasite that causes malaria.
C. Salmonella typhimurium, a gram negative microbe that can cause severe intestinal disease.
D. Mycoplasma pneumoniae, a microbial cause of pneumonia.

Answer: C. Salmonella typhimurium, a gram negative microbe that can cause severe intestinal disease.

Which of the following statements is true?

Which of the following statements is true?

A. Endospores are for reproduction.
B. Endospores allow a cell to survive environmental changes.
C. A cell produces one endospore and keeps growing.
D. A cell can produce many endospores.


Answer: B. Endospores allow a cell to survive environmental changes.

Positive phototaxis describes ___.

Positive phototaxis describes ___.

A. Movement towards a light source.
B. Movement away from a light source.
C. Rotation nearby a light source.
D. Energy production from a light source.


Answer: A. Movement towards a light source.

Which of the following molecules would be blocked by a cell membrane?

Which of the following molecules would be blocked by a cell membrane?

A. Carbon dioxide
B. Ions
C. Water
D. Oxygen


Answer: B. Ions

Antibiotics that target the cell wall are an effective treatment against pathogenic bacteria.

Antibiotics that target the cell wall are an effective treatment against pathogenic bacteria.

A. True
B. False


Answer: A. True

Which of the following is not a characteristic of the plasma membrane?

Which of the following is not a characteristic of the plasma membrane?

A. Composed of a phospholipid bilayer.
B. Maintains cell shape
C. Selectively permeable
D. Contains proteins


Answer: B. Maintains cell shape.

What is responsible for making proteins?

What is responsible for making proteins?

A. DNA
B. Rough ER
C. ATP
D. mRNA
E. Ribosomes


Answer: E. Ribosomes

Oxygen crosses a plasma membrane ___.

Oxygen crosses a plasma membrane ___.

A. By osmosis
B. Through simple diffusion
C. With the help of a nonspecific transporter.
D. Through facilitated diffusion
E. Through porins.


Answer: B. Through simple diffusion

Which of these is not considered a part of bacterial cytoplasm?

Which of these is not considered a part of bacterial cytoplasm?

A. Nucleoid
B. LPS
C. Endospore
D. An inclusion


Answer: A. Nucleoid

What will happen if a bacterial cell is placed in 10% NaCI (hypertonic)?

What will happen if a bacterial cell is placed in 10% NaCI (hypertonic)?

A. The cell will undergo plasmolysis.
B. The cell will undergo osmotic lysis.
C. Active transport will be activated
D. NaCI will rush into the cell.


Answer: A. The cell will undergo plasmolysis.

Each of following statements concerning the gram-positive cell wall is true except ___.

Each of following statements concerning the gram-positive cell wall is true except ___.

A. It maintain the shape of the cell.
B. It is sensitive to penicillin.
C. It protects the cell in a hypertonic environment.
D. It contains teichoic acids
E. It is made of peptidoglycan.


Answer: C. It protects the cell in a hypertonic environment.

Antibiotics that target cell wall synthesis ultimately cause bacterial cell death as a result of ___.

Antibiotics that target cell wall synthesis ultimately cause bacterial cell death as a result of ___.

A. Lysis
B. Inhibition of molecular transport.
C. Decreased synthesis of peptidoglycan.
D. Plasmolysis
E. Cell shrinkage.


Answer: A. Lysis

Which of the following statements is correct about simple diffusion?

Which of the following statements is correct about simple diffusion?

A. It requires an expenditure of energy by the cell.
B. Is is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
C. Is is an active process in which molecules move from a region of lower concentration to on of higher concentration.
D. It may require a transport protein.
E. It involves movement of molecules down a concentration gradient and may require a transport protein.


Answer: B. Is is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.

Which of the following organelles are responsible for generating ATP?

Which of the following organelles are responsible for generating ATP?

A. Ribosomes
B. Golgi complex
C. Lysosome
D. Mitochondria
E. Chloroplasts


Answer: D. Mitochondria

What of these processes requires energy?

What of these processes requires energy?

A. Simple diffusion
B. Facilitated diffusin
C. Active transport


Answer: C. Active transport

Which bacterial genus does not have a cell wall?

Which bacterial genus does not have a cell wall?

A. Mycobacterium
B. Streptococcus
C. Mycoplasma
D. Bacillus
E. Staphylococcus


Answer: C. Mycoplasma

The shape of a bacterial cell is determined primarily by the ___.

The shape of a bacterial cell is determined primarily by the ___.

A. Cell membrane
B. Cell wall
C. Capsule
D. Slime layer
E. Flagella


Answer: B. Cell wall

What would likely occur to a halophile (salt-loving bacteria) that's placed into high salt environment?

What would likely occur to a halophile (salt-loving bacteria) that's placed into high salt environment?

A. The cell would plasmolyse.
B. The cell would osmolyse.
C. No major effect.


Answer: C. No major effect.

Small hydrophobic molecules would likely enter a cell ___.

Small hydrophobic molecules would likely enter a cell ___.

A. By active transport directly across the membrane.
B.Through integral transport proteins.
C. By passive transport directly across the membrane.
D. With the requirement of energy.


Answer: C. By passive transport directly across the membrane.

What makes phospholipid membranes good at keeping some molecules out, and allowing others to freely pass?

What makes phospholipid membranes good at keeping some molecules out, and allowing others to freely pass? 

A. They are positive charged.
B. They have both hydrophilic and hydrophobic regions.
C. They are completely hydrophilic.
D. They are completely hydrophobic.


Answer: B. They have both hydrophilic and hydrophobic regions.

Penicillins show great selective toxicity because ____.

Penicillins show great selective toxicity because ____.

A. They are very simple to create.
B. They are enzymes.
C. Peptidoglycan is not found in human cells.
D. Bacterial plasma membranes are different from eukaryotic membranes.
E. They are too large to affect eukaryotic cells.


Answer: C. Peptidoglycan is not found in human cells.

What is the similarity between facilitated diffusion and active transport?

What is the similarity between facilitated diffusion and active transport?

A. Both require energy.
B. Both require transport proteins.
C. Both move molecules down the concentration gradient.
D. Both move molecules up the concentration gradient.
E. Both involve the flow of water.


Answer: B. Both require transport proteins.

Where are phospholipids most likely found in a eukaryotic cell?

Where are phospholipids most likely found in a eukaryotic cell? 

A. Ribosomes
B. Around organelles
C. Flagella
D. Plasma membrane
E. Both the plasma membrane and organelles.


Answer: E. Both the plasma membrane and organelles.

In a Gram-negative, the peptidoglycan layer exists ____.

In a Gram-negative, the peptidoglycan layer exists ____.

A. In the periplasm.
B. Underneath the plasma membrane, inside the cell.
C. On top of the outer membrane, outside of the cell.
D. Anchored by teichoic acid.


Answer: A. In the periplasm.

Which of the following is not a common bacterial shape?

Which of the following is not a common bacterial shape? 

A. Spirochete
B. Coccus
C. Square
D. Bacillus


Answer: C. Square

A sodium ion can pass through the plasma membrane because the positive charge allows it to bind to the negative phospholipid.

A sodium ion can pass through the plasma membrane because the positive charge allows it to bind to the negative phospholipid.

A. True
B. False


Answer: B. False

Which of the following is an example of a metabolic activity that could be used to measure microbial growth?

Which of the following is an example of a metabolic activity that could be used to measure microbial growth? 

A. Standard plate count
B. Glucose consumption
C. Direct microscopic count
D. Turbidity
E. MPN


Answer: B. Glucose consumption

Which of these quantification methods would be most accurate when quantifying a filamentous mold culture?

Which of these quantification methods would be most accurate when quantifying a filamentous mold culture?

A. Plate count
B. Filtration
C. Turbidity
D. Dry weight
E. MPN


Answer: D. Dry weight

Which nutritional requirement is iron (Fe2+) considered to be a part of?

Which nutritional requirement is iron (Fe2+) considered to be a part of?

A. The major nutritional elements
B. Trace elements
C. Organic growth factors
D. Vitamins
E. A physical requirement


Answer: B. Trace elements

During which phases of the bacterial growth curve are there no changes in the number of living cells?

During which phases of the bacterial growth curve are there no changes in the number of living cells? 

A. Stationary and death phase
B. Lag phase and log phase
C. Log phase and stationary phase
D. Lag phase and stationary phase
E. Lag phase


Answer: D. Lag phase and stationary phase

At which stage of bacterial growth is cell division the most rapid?

At which stage of bacterial growth is cell division the most rapid? 

A. Lag
B. Log
C. Stationary
D. Death


Answer: B. Log

Cells that live in high salt environments are called ________.

Cells that live in high salt environments are called ________. 

A. plasmophiles
B. saltophiles
C. tonophiles
D. halophiles


Answer: D. halophiles

Which of these does not contain nitrogen?

Which of these does not contain nitrogen?

A. Carbohydrates
B. Proteins
C. DNA
D. RNA


Answer: A. Carbohydrates

Which of these microbes would not contain superoxide dismutase?

Which of these microbes would not contain superoxide dismutase?

A. Obligate aerobe
B. Facultative aerobe
C. Obligate anaerobe
D. Aerotolerant anaerobe


Answer: C. Obligate anaerobe

All of the following are true about agar except ______.

All of the following are true about agar except ______.

A. it is a source of nutrients in culture media
B. it is a polysaccharide
C. it solidifies below 40'C
D. it is used to harden liquids


Answer: A. it is a source of nutrients in culture media

The large intestine is an environment that lacks any oxygen. Which of the following types of organisms would most likely be found there?

The large intestine is an environment that lacks any oxygen. Which of the following types of organisms would most likely be found there? 

A. Obligate aerobe
B. Obligate anaerobe
C. Microaerophile
D. Aerotolerant anaerobe


Answer: B. Obligate anaerobe

What toxic oxygen form of oxygen does the enzyme catalase detoxify?

What toxic oxygen form of oxygen does the enzyme catalase detoxify? 

A. Superoxide free radical
B. Singlet oxygen
C. Peroxide anion
D. Hydroxyl radical


Answer: C. Peroxide anion

While ____ is able to detoxify a reactive oxygen species, it also produces one, hydrogen peroxide.

While ____ is able to detoxify a reactive oxygen species, it also produces one, hydrogen peroxide.

A. Superoxide dismutase
B. Catalase
C. Peroxidase
D. Oxygenase


Answer: A. Superoxide dismutase

At which stage of bacterial growth does cell division NOT occur?

At which stage of bacterial growth does cell division NOT occur? 

A. Lag
B. Log
C. Stationary
D. Death


Answer: A. Lag

Lactic acid bacteria, the bacteria involved in making kimchi and yogurt, are strict fermenters. What can you say about their requirements for oxygen?

Lactic acid bacteria, the bacteria involved in making kimchi and yogurt, are strict fermenters. What can you say about their requirements for oxygen? 

A. Obligate Aerobe
B. Obligate Anaerobe
C. Facultative Anaerobe
D. Aerotolerant Anaerobes
E. Microaerophiles


Answer: D. Aerotolerant Anaerobes

Penicillin functions by inhibiting the formation of new cell walls. At what stage of bacterial growth is penicillin most effective? Hint - when do you think cells are making new cell walls?

Penicillin functions by inhibiting the formation of new cell walls. At what stage of bacterial growth is penicillin most effective? Hint - when do you think cells are making new cell walls? 

A. Lag
B. Log
C. Stationary
D. Phase


Answer: B. Log

You want to quantify a culture of motile bacteria. Which method of quantifying would you use if you needed the most accurate information as soon as possible?

You want to quantify a culture of motile bacteria. Which method of quantifying would you use if you needed the most accurate information as soon as possible?

A. Plate count
B. MPN
C. Turbidity
D. Microscopic count
E. Dry weight


Answer: C. Turbidity

Salts and sugars work to preserve foods by creating a ____.

Salts and sugars work to preserve foods by creating a ____. 

A. lower osmotic pressure
B. hypotonic environment
C. lower pH
D. hypertonic environment


Answer: D. hypertonic environment

Which of the following is the best definition of generation time?

Which of the following is the best definition of generation time? 

A. The length of time needed for lag phase
B. The length of time needed for a cell to divide
C. The minimum rate of doubling
D. The duration of log phase
E. The time needed for nuclear division


Answer: B. The length of time needed for a cell to divide

What is the difference between peroxidase and catalase?

What is the difference between peroxidase and catalase? 

A. Peroxidase detoxifies hydrogen peroxide, catalase detoxifies hydroxyl radicals.
B. Catalase produces oxygen, peroxidase does not.
C. Aerotolerant anaerobes use catalase, facultative anaerobes use peroxidase
D. Obligate aerobes use both peroxidase and catalase


Answer: B. Catalase produces oxygen, peroxidase does not.

Most human pathogens are _________.

Most human pathogens are _________.

A. psychrophiles
B. mesophiles
C. thermophiles
D. psychrotrophs


Answer: B. Mesophiles

Which method of quantifying bacterial numbers would be most effective for measuring the numbers of bacteria in drinking water, when you expect the numbers to be relatively low?

Which method of quantifying bacterial numbers would be most effective for measuring the numbers of bacteria in drinking water, when you expect the numbers to be relatively low?

A. Filtration
B. Plate count
C. Direct microscopic count
D. Turbidity


Answer: A. Filtration

Which pH is considered alkaline?

Which pH is considered alkaline?

A. 4
B. 2
C. 7
D. 10


Answer: D. 10

The term aerotolerant anaerobe refers to an organism that ______.

The term aerotolerant anaerobe refers to an organism that ______.

A. does not use oxygen but tolerates it
B. is killed by oxygen
C. uses oxygen or grows without oxygen
D. requires less oxygen than is present in air
E. requires more oxygen than is present in air


Answer: A. does not use oxygen but tolerates it

In which phase is the rate of cell death equal to the rate of cell growth?

In which phase is the rate of cell death equal to the rate of cell growth? 

A. Log phase
B. Death phase
C. Log and death phase
D. Stationary phase
E. Log and stationary phase


Answer: D. Stationary phase

Luria Broth (LB) is a medium containing Tryptone, yeast extract, and sodium chloride.

Luria Broth (LB) is a medium containing Tryptone, yeast extract, and sodium chloride. 

A. LB is a chemically defined medium.
B. LB is a complex medium.
C. There is not enough information presented.
D. Depends if agar is present or not.


Answer: B. LB is a complex medium.

Coffee has a pH of approximately 5. What type of microbe can grow in your coffee?

Coffee has a pH of approximately 5. What type of microbe can grow in your coffee? 

A. acidophile
B. alkalinophile
C. halophile
D. extreme halophile


Answer: A. acidophile

Why might cells begin to die at a faster rate than new cells are made?

Why might cells begin to die at a faster rate than new cells are made?

A. Original cells get too old.
B. Increase in cellular waste products.
C. Lack of nutrients and an increase in cellular waste products.
D. Cells can only divide a certain number of times before they die.
E. Lack of nutrients.


Answer: C. Lack of nutrients and an increase in cellular waste products.

Most bacteria reproduce by ______.

Most bacteria reproduce by ______.

A. sexual reproduction
B. binary fission
C. budding
D. mitosis


Answer: B. binary fission

Which of these microbes is most problematic to human health?

Which of these microbes is most problematic to human health? 

A. Psychrophiles
B. Psychrotrophs
C. Mesophiles
D. Thermophiles
E. Hyperthermophiles


Answer: C. Mesophiles

Bacterial growth is defined as _____.

Bacterial growth is defined as _____.

A. increase in bacterial cell population
B. increase in cell length
C. increase in cellular proteins
D. increase in cell metabolic processes


Answer: A. increase in bacterial cell population

Aerobic bacteria that have developed (or retain) the ability to continue growing in the absence of oxygen are called _____.

Aerobic bacteria that have developed (or retain) the ability to continue growing in the absence of oxygen are called _____. 

A. obligate anaerobes
B. obligate aerobes
C. facultative anaerobes
D. aerotolerant anaerobes


Answer: C. facultative anaerobes

Which of the following organisms most likely does not have catalase?

Which of the following organisms most likely does not have catalase?

A. An aerotolerant anaerobe.
B. An obligate anaerobe.
C. A facultative anaerobe.
D. An obligate aerobe


Answer: B. An obligate anaerobe.

Which of the following is an advantage of the standard plate count?

Which of the following is an advantage of the standard plate count? 

A. Can readily count cells that form aggregates.
B. Determines the number of live cells within a population.
C. Can be performed on very dilute samples, such as lake water
D. Provides immediate results
E. Can be used to count heat-sensitive bacteria


Answer: B. Determines the number of live cells within a population.

Protein synthesis during lag phase is not occurring because cells are not actively dividing.

Protein synthesis during lag phase is not occurring because cells are not actively dividing.

A. True
B. False


Answer: B. False

Thirty-six colonies grew on nutrient agar from 1.0 ml of undiluted sample in a standard plate count. How many cells were in the original sample?

Thirty-six colonies grew on nutrient agar from 1.0 ml of undiluted sample in a standard plate count. How many cells were in the original sample?

A. 4
B. 9
C. 18
D. 36
E. 72


Answer: D. 36

Which of the following is an advantage of the direct microscopic count?

Which of the following is an advantage of the direct microscopic count?

A. Can readily count organisms that are motile.
B. Can easily distinguish live from dead cells.
C. Requires no incubation time.
D. Sample volume is unknown.
E. Requires a large number of cells.


Answer: C. Requires no incubation time.

Which of these organisms would not be able to grow in water that has oxygen pumped into it (aerated)?

Which of these organisms would not be able to grow in water that has oxygen pumped into it (aerated)?

A. Obligate aerobe
B. Facultative aerobe
C. Obligate anaerobe
D. Aerotolerant anaerobe


Answer: C. Obligate anaerobe

Which of these microbes is most likely to grow at room temperature (25 C)?

Which of these microbes is most likely to grow at room temperature (25 C)?

A. Psychrophile
B. Psychrotroph
C. Thermophile
D. Hyperthermophile


Answer: B. Psychrotroph

Shoyu is highly salty (often higher than 28%). What type of microbe can grow in shoyu?

Shoyu is highly salty (often higher than 28%). What type of microbe can grow in shoyu?

A. acidophile
B. alkalinophile
C. halophile
D. extreme thermophile


Answer: C. halophile

Organisms that grow near deep‐sea volcanic vents are likely to be

Organisms that grow near deep‐sea volcanic vents are likely to be

A) psychrophilic.
B) psychrotrophic.
C) mesophilic.
D) thermophilic.


Answer: D) thermophile

When a microorganism is placed in a(n) __________ solution, water will enter into the cell and cause it to burst unless something is done to prevent this.

When a microorganism is placed in a(n) __________ solution, water will enter into the cell and cause it to burst unless something is done to prevent this.

A) hypotonic
B) isotonic
C) hypertonic
D. osmotonic


Answer: A) Hypotonic

Organisms that are damaged by the normal atmospheric levels of oxygen (20%) but require oxygen at levels of 2-10% for growth are called

Organisms that are damaged by the normal atmospheric levels of oxygen (20%) but require oxygen at levels of 2-10% for growth are called

A) facultative anaerobes.
B) microaerophiles.
C) aerotolerant.
D) anoxygenic.


Answer: B) microaerophiles

Organisms that do not require oxygen for growth but grow better in its presence are called

Organisms that do not require oxygen for growth but grow better in its presence are called

A) facultative anaerobes.
B) microaerophiles.
C) aerotolerant.
D) anoxygenic.


Answer: A) Facultative anaerobes

Which of the following is considered a cardinal growth temperature?

Which of the following is considered a cardinal growth temperature?

A) the minimum temperature
B) the maximum temperature
C) the optimum temperature
D) All of these are considered cardinal growth temperatures.


Answer: D)

Which of the following can be used to estimate the number of microorganisms in a culture?

Which of the following can be used to estimate the number of microorganisms in a culture?

A) direct counts of microbial cells
B) counts of viable cells using colony growth procedures
C) measurements of microbial biomass
D) all of the choices


Answer: D)

The length of the bacterial lag phase of growth can vary depending on

The length of the bacterial lag phase of growth can vary depending on

A) the condition of the microorganisms.
B) the nature of the growth medium.
C) the temperature.
D) all of the choices



Answer: D)

All of the choices ( condition of the microorganisms, the nature of the growth medium, temperature)

A culture in a closed vessel to which no additional medium is added and from which no waste products are removed is called a __________ culture.

A culture in a closed vessel to which no additional medium is added and from which no waste products are removed is called a __________ culture.

A) continuous
B) batch
C) fed‐batch
D) semicontinuous


Answer: B) Batch

Most bacterial and archaeal cells divide by

Most bacterial and archaeal cells divide by

A) mitosis
B) meiosis
C) binary fission
D) all of the above


Answer: C) Binary Fission

Differential media make it easier to distinguish colonies of different microbes

Differential media make it easier to distinguish colonies of different microbes

A) True
B) False


Answer: A) True

Microbes that require higher CO2 levels that are found in air are called

Microbes that require higher CO2 levels that are found in air are called

A) facultative anaerobes
B) microaerophiles
C) capnophiles
D) aerobes
E) fastidious


Answer: C) Capnophiles

Which of the following is not generally true about biofilms?

Which of the following is not generally true about biofilms?

A) They may be considered microbial communities
B) The organisms in them do not share nutrients
C) They are much more resistant to drugs, in particular microbicides
D) They usually begin when a free‐swimming bacterium attaches to a surface
E) The CDC estimates that 70% of human bacterial infections involve biofilms


Answer: B) The organisms in them do not share nutrients

Which of the following uses inorganic molecules such as H2S as an energy source?

Which of the following uses inorganic molecules such as H2S as an energy source?

A) lithotrophs
B) chemotrophs
C) photoptrophs
D) aerobes?


Answer: B) Chemotrophs

An organic compound such as an amino acid or vitamin that cannot be synthesized by an organism and must be provided as a nutrient is called a

An organic compound such as an amino acid or vitamin that cannot be synthesized by an organism and must be provided as a nutrient is called a

A) key compound
B) growth factor
C) cofactor
D) coenzyme
E) complex nutrient


Answer: D) Coenzyme

Organisms that must obtain their carbon in organic form are called

Organisms that must obtain their carbon in organic form are called

A) parasites
B) photosynthesizers
C) heterotrophs
D) autotrophs


Answer: C) Heterotrophs <-- cannot fix N2, need plants

Some microbes can transform N2 into usable compounds; this is achieved by the process of

Some microbes can transform N2 into usable compounds; this is achieved by the process of

A) Photosynthesis
B) Nitrogen fixation
C) Nitrogen reduction
D) Anabolism
E) Fermentation


Answer: B) Nitrogen fixation

Which of the following is an organic growth factor?

Which of the following is an organic growth factor?

A) glucose
B) vitamin B
C) peptone
D) Na2HPO4
E) H2O


Answer: B) Vitamin B

A sample of milk is tested for its bacterial content in a plate count assay. A one-milliliter sample of the milk is diluted in a 1:10 dilution series. One milliliter of the third dilution tube is plated in a pour plate. After incubation, the plate has 54 colonies, indicating that the original milk sample contained

A sample of milk is tested for its bacterial content in a plate count assay. A one-milliliter sample of the milk is diluted in a 1:10 dilution series. One milliliter of the third dilution tube is plated in a pour plate. After incubation, the plate has 54 colonies, indicating that the original milk sample contained

a. 540,000 cells.
b. 540 cells.
c. 54,000 cells.
d. 54 cells.
e. 5,400 cells. c. 54,000 cells.


Answer: C) ,

3RD DILUTION PLATE, 10^-3, 54=54000

Patients with indwelling catheters are susceptible to infections because

Patients with indwelling catheters are susceptible to infections because

A) Injected solutions are contaminated.
B) Their immune systems are weakened.
C) Infections can be transmitted from other people.
D) Biofilms develop on catheters.
E) Bacteria cause infections.


Answer: D) BIOFILMS! develop on catheters

Three cells with generation times of 30 minutes are inoculated into a culture medium. How many cells are there after 5 hours?

Three cells with generation times of 30 minutes are inoculated into a culture medium. How many cells are there after 5 hours?

A) 3072
B) 1024
C) 243
D) 48


Answer: A) =10 generations, 3-6-12-24-48-96-192-384-768-1536-3072 therefore answer is 3072

An experiment began with 4 cells and ended with 128 cells. How many generations did the cells go through?

An experiment began with 4 cells and ended with 128 cells. How many generations did the cells go through?

A) 64
B) 32
C) 6
D) 5
E) 4


Answer: D) 4-8-16-32-64-128, each - equal 1 generation, therefore the answer is 5

Which of the following is an example of a metabolic activity that could be used to measure microbial growth?

Which of the following is an example of a metabolic activity that could be used to measure microbial growth?

A) Standard plate count
B) Glucose consumption
C) Direct microscopic count
D) MPN


Answer: B) Glucose consumption

Which group of microorganisms is most likely to spoil a freshwater trout preserved with salt?

Which group of microorganisms is most likely to spoil a freshwater trout preserved with salt?

A) Psychrophiles
B) Facultative halophiles
C) Anaerobes
D) Thermophiles
E) Hyperthermophiles


Answer: B) Facultative Halophiles -Have the ability to grow at high salt concentrations

Which of the following is NOT a direct method to measure microbial growth?

Which of the following is NOT a direct method to measure microbial growth?

A) Direct microscopic count
B) Standard plate count
C) Filtration
D) Metabolic activity


Answer: D) Metabolic activity

Which of the following is the best definition of generation time?

Which of the following is the best definition of generation time?

A) The length of time needed for lag phase
B) The length of time needed for a cell to divide
C) The minimum rate of doubling
D) The duration of log phase
E) The time needed for nuclear division


Answer: B) The length of time needed for a cell to divide

During which growth phase will gram‐positive bacteria be most susceptible to penicillin?

During which growth phase will gram‐positive bacteria be most susceptible to penicillin?

A) Lag phase
B) Log phase
C) Death phase
D) Stationary phase
E) The culture is equally susceptible during all phases.


Answer: B) Log phase

Which of the following pairs is mismatched?

Which of the following pairs is mismatched?

A) Psychrotroph - growth at 37°C
B) Thermophile - growth at 60°C
C) Mesophile - growth at 25°C
D) Psychrophile - growth at 15°C


Answer: A) Psychrotroph - growth at 37 C

A culture medium consisting of agar, human blood, and beef heart is a

A culture medium consisting of agar, human blood, and beef heart is a

A) Chemically defined medium.
B) Complex medium.
C) Selective defined medium.
D) Differential defined medium.


Answer: B) Complex medium

Most bacteria grow best at pH

Most bacteria grow best at pH

A) 1.
B) 5.
C) 7.
D) 9.


Answer: C) 7, neutral

In Figure 2, which sections of the graph illustrate a logarithmic change in cell numbers?

In Figure 2, which sections of the graph illustrate a logarithmic change in cell numbers?

A) a and c
B) b and d
C) a and b
D) c and d


Answer: B) b&d Lag and Death phase

In Figure 2, which sections show a phase where the number of cells dying equals the number of new cells being produced?

In Figure 2, which sections show a phase where the number of cells dying equals the number of new cells being produced?

A) a and c
B) b and d
C) a and b
D) c and d


Answer: A) a&c Lag and Stationary phase

Thirty‐six colonies grew in nutrient agar from 1.0 ml of undiluted sample in a standard plate count. How many cells were in the original sample?

Thirty‐six colonies grew in nutrient agar from 1.0 ml of undiluted sample in a standard plate count. How many cells were in the original sample?

A) 4
B) 9
C) 18
D) 36


Answer: D) 36

Which of the following is an advantage of the standard plate count?

Which of the following is an advantage of the standard plate count?

A) Can readily count cells that form aggregates
B) determines the number of viable cells
C) can be performed on very dilute samples, such as lake water
D) provides immediate results
E) Can be used to count heat‐sensitive bacteria


Answer: B) Determines # of viable cells

Which of the following is an advantage of the direct microscopic count?

Which of the following is an advantage of the direct microscopic count?

A) Can readily count organisms that are motile
B) Easily counts dead cells
C) Requires no incubation time
D) Requires a large number of cells


Answer: C) Requires no incubation time

The term facultative anaerobe refers to an organism that

The term facultative anaerobe refers to an organism that

A) Doesn't use oxygen but tolerates it.
B) Is killed by oxygen.
C) Uses oxygen or grows without oxygen.
D) Requires less oxygen than is present in air.


Answer: C) Uses oxygen or grows without oxygen

Salts and sugars work to preserve foods by creating a

Salts and sugars work to preserve foods by creating a

A) Depletion of nutrients.
B) Hypotonic environment.
C) Lower osmotic pressure.
D) Hypertonic environment.


Answer: D) HYPERtonic environment. Water moves out of the cell.

The addition of which of the following to a culture medium will neutralize acids?

The addition of which of the following to a culture medium will neutralize acids?

A) Buffers
B) Sugars
C) pH
D) Carbon


Answer: A) Buffers!