microbiology

Which of the following terms describes "cell drinking"?

pinocytosis

Which of the following is NOT a classification of viruses?

presence of an enzyme are type of nucleic acid capsid symmetry architecture of genome

Which of the following is a function of the eukaryotic glycocalyx?

protect the cell from external stress

_______________ are on by default, meaning they are actively transcribed until they are switched off (repressed).

repressible operons

What intercellular structure builds proteins by linking amino acids together?

ribosomes

Certain bacteria can form endospores in order to

survive harsh conditions

A Gram-positive bacterium contains which of the following?

teichoic acid

What does sensitivity mean?

the diagnostic test detects a very low level of the target to limit false negative results

Which of the following viral infections is cleared out by the host immune system?

acute

Which of the following nitrogenous bases is a purine?

adenine

What characteristic of the eukaryotic glycocalyx distinguishes it from a prokaryotic glycocalyx?

aiding in tissue development

Which of the following produces alcohol, carbon dioxide, and a small amount of energy?

alcoholic fermentation

What happens when an enzyme is above optimal temperature conditions?

alters enzyme structure denatures reduces reaction time

Why do we need new and different flu shots every year?

antigenic drift

What was the Ames test developed for?

to quickly identify mutagens that alter DNA by base substitutions or frameshift mutations

Which type of RNA brings the correct amino acid to a ribosome to build a protein?

transfer RNA

RNA is distinguished from DNA because only RNA:

typically exists as a single-stranded molecule

Which flagella allows spirochetes to move with their distinct corkscrew motion?

periplasmic

Select the best definition of metabolism.

Metabolism refers to all of the chemical reactions in a cell that impact energy use and release.

Choose the true statement(s) about plasmids.

Plasmids tend to exist outside of a cell's chromosome. Plasmid tend to be circular. Plasmids often contain genes that confer a survival advantage to a cell.

Thymine dimers are cause by _____________ which interfere with DNA replication and transcription.

UV radiation

Choose the true statement(s) about stop codons.

Under specific circumstances, stop codons may encode non-standard amino acids. There are several stop codons in the genetic code.

Which test media usually contain a protein, a single carbohydrate, a pH indicator, and sometimes an inverted Durham tube to capture gas?

fermentation tests

Which of the following is NOT a part of the prokaryotic cell structure?

lysosome are ribosome cytoplasm plasma membrane

Azathioprine is a drug that may be prescribed to transplant recipients to reduce the chance of tissue rejection reactions. In its active state, it acts as a purine analogue, inhibiting DNA biosynthesis. This means that 6-mercaptopurine will be inserted in place of a purine containing nucleotides during DNA replication. Given this drug's mode of action, you would expect it to be incorporated into DNA in place of

nucleotides containing adenine or guanine.

Where does transcription occur in an eukaryotic cell?

nucleus

Disease-causing microbes that must invade living cells and hijack their biochemical and cellular tools are called:

obligate intracellular pathogens

An atom or molecule loses electrons in a ________________ reaction.

oxidation

What is the core compound in many fungal cell walls?

chitin

__________ are a collection of tubular structures, either septate or aseptate, which allow for growth in most fungi.

Hyphae

Which of the following observations supports the statement that cytomegalovirus (CMV) has a remarkably broad tropism?

CMV can infect connective tissue cells and parenchymal cells of virtually any organ.

Which of the following is (are) used to classify viruses?

Capsid symmetry Type of nucleic acid present

What are the three main fibers of the eukaryotic cytoskeleton?

microtubules, intermediate filaments, and microfilaments

Which external structure provides some protection against host immune cells from interfering with phagocytosis?

capsule

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

6

Choose the true statement(s) about biochemical tests.

A biochemical test may detect intermediates or end-products in a pathway. A biochemical test can detect what enzymes a bacterium makes.

Compared to eukaryotic genomes, only prokaryotic genomes:

contain usually one, circular chromosome.

In the Spring of 2009, a novel H1N1 virus emerged that had a new combination of genes from pigs, humans, and birds. As a result, the virus spread quickly, resulting in a swine flu pandemic. Which of the following concepts explains why the outbreak occurred?

Antigenic shift

After incubation, you observe that your streak-plate has heavy, uniform growth but no isolated colonies. Which of the following could explain this result?

Area three of the streak plate crossed into area one of the streak plate. The loop was not properly sterilized between plate sections.

Microbes that can live in both aerobic and anaerobic environments are called?

facutative anaerobes

Which of the following is mismatched?

Ascospores; asexual reproduction Correct Basidiospores: sexual spores found in mushroom Sporangiospores: asexual spores Zygospores: sexual reproduction

You are a manufacturer of polypropylene hypodermic syringes. Which of the following methods would be best for ensuring sterility of this heat-sensitive material?

Ionizing radiation

Which of the following names represents a viral order?

Mononegravirales

Which of the following is not a mechanism for horizontal gene transfer?

Binary fission are Transduction Transformation Conjugation

Which of the following is a key distinguishing characteristic between budding and binary fission?

Binary fission results in daughter cells of equal size, whereas budding is an uneven division

The end product of meiosis is

four genetically different haploid cells.

Which organisms can survive in high salt environments?

halophiles

Which of the following is not needed to carry out excision repair in Escherichia coli?

helicase are DNA polymerase I DNA ligase Excision complex

When we say that catabolic and anabolic reactions are coupled, what does that really mean?

Catabolic reactions provide energy and smaller molecules required by anabolic reactions.

Choose the true statement(s) about ATP.

Catabolizing one lipid molecule would produce more ATP for a cell than catabolizing one glucose molecule. ATP is made by phosphorylating ADP.

Choose the true statement(s) about mutations.

Mutations can provide an evolutionary benefit. Mutation leads to genetic and phenotypic variation within a species. In humans, somatic cell mutations are not passed to offspring.

Choose the true statement(s) about conjugation.

Conjugation involves the formation of a pilus for gene transfer. Conjugation is a form of horizontal gene transfer. Conjugation allows for antibiotic resistance traits to be passed from one bacterium to another.

Which of the following is an example of a spontaneous mutation?

DNA polymerase III accidently mismatches a G to a T during Escherichia coli DNA replication, resulting in a silent mutation.

Which of the following contributes to DNA replication accuracy?

DNA replication accuracy is improved thanks to complementary base pairing rules. The capacity to proofread improves DNA replication accuracy.

Choose the true statement(s) about acid-fast bacteria.

Genera Nocardia and Mycobacterium are acid-fast and stain pink during the acid-fast staining procedure. Acid-fast bacteria have a waxy lipid called mycolic acid in their cell walls. Acid-fast staining is important in the diagnosis of leprosy and tuberculosis.

Which of the following strategies can be used to treat drinking water, ensuring that it is not contaminated with protozoans such as Cryptosporidium parvum?

Filtration Exposure to ultraviolet light Ozone treatment

Of the following animal kingdoms listed, which of the following can be unicellular?

Fungi and Protists

In Gram-positive bacteria, ______ rings secure the flagellum, while in Gram-negative bacteria, the flagella are anchored by _____ rings.

2,4

Binary fission occurs in the following 5 steps, arrange the following steps: 1. Daughter cells separate 2. Septum starts to form 3. Cell is partitioned 4. DNA replicates 5. Cell elongates

4, 5, 2, 3, 1

Alanine is a non-essential amino acid in humans. Based on this, select the true statement about alanine.

Alanine is made in human cells as the result of an amination reaction.

Choose the true statement(s) about prokaryotic cells.

All prokaryotes are unicellular organisms. Most of a prokaryote's nutrients are obtained through diffusion. All prokaryotes lack a membrane-bound nucleus and organelles.

Which of the following is the best definition of the term amphibolic pathway?

An amphibolic pathway is one that functions simultaneously in catabolism and anabolism.

Choose the true statement(s) about coenzymes.

An example of a coenzyme is FAD. An example of a coenzyme is NAD+. Coenzymes are often vitamins or are made from vitamins.

Which of the following is an unsuitable culture method for an animal virus?

Direct inoculation of virus onto blood agar

Choose the false statement regarding prokaryotic plasma membranes.

Ions and large polar substances can diffuse through the plasma membrane without assistance. True Gases, water, and small non-charged substances can diffuse through the selectively permeable plasma membrane. The plasma membrane's phospholipid bilayer contains hydrophilic phosphates and hydrophobic fatty acids. The plasma membrane is a phospholipid bilayer that serves as barrier for a cell.

Which of the following is a valid difference between the leading and lagging strands in DNA replication?

On the leading strand, only a single RNA primer is needed to initiate continuous DNA synthesis.

Choose the true statement about the Domain Bacteria.

The Domain Bacteria is made up of prokaryotes and likely originated 3.8 billion years ago.

Which of the following is true regarding the bacterial plasma membrane only, and not the archaeal plasma membrane?

The bacterial plasma membrane only occurs as a bilayer.

Select the procedure(s) that would be used to identify an unknown bacterium in a patient sample

The bacterium should be grown in a pure culture and subjected to multiple biochemical tests. The specimen should be observed using microscopy.

Which of the following definitions is correct for catabolic pathways?

break down substances and releases energy

__________________ is when amino acids are broken down and then catabolized in the Krebs cycle?

deamination

All of the following are examples of inclusion bodies in prokaryotic cells except __________.

endospores these are carboxysomes magnetosomes glycogen granules

Viruses are considered nonliving for all of the following reasons EXCEPT:

viruses only have a small number of genes

What is the primary difference between a disinfectant and an antiseptic?

A disinfectant is used to decontaminate lifeless objects, whereas an antiseptic is applied to living tissue.

What is the only ciliated protozoan known to cause human disease?

Balantidium coli

Which of the following could serve as a final electron acceptor in an anaerobic respiratory chain?

Carbonate (CO32-)

Chlamydia trachomatis is an obligate intracellular bacterium that causes the sexually transmitted disease chlamydia. When this bacterium was first discovered, it was classified as a virus. However, it was later re-classified as a bacterium. Which of the following is the most likely reason why C. trachomatis was reclassified as a living bacterial cell as opposed to a nonliving viral particle?

Chlamydia trachomatis is capable of performing metabolic processes.

Choose the true statement about cilia and flagella.

Cilia and flagella are surrounded by a membrane and sprout from centrioles.

Which of the following virus RNA families relate to the common cold?

Coronaviridae

Your patient is receiving a spinal fusion to correct a skeletal defect. Which of the following germicides is recommended to sterilize the bone used for the transplantation?

Ethylene oxide

Choose the true statement about prokaryotic and eukaryotic DNA replication.

Eukaryotic DNA replication begins at multiple origins of replication, while prokaryotic DNA replication begins at a single origin of replication.

Choose the correct pairing.

Eukaryotic flagella: 9 + 2 microtubule arrangement

Choose the true statement(s) about DNA replication.

Every replication fork will have both a leading and a lagging strand.

Which of the following is found in a mature eukaryotic mRNA molecule?

Exons Start codon

Which of the following requires an external source of organic carbon in order to live and grow?

heterotrophs

What organizational protein keeps Eukaryotic chromosomes from getting tangled?

histones

What is another term used to describe the Citric Acid Cycle?

kreb cycle

Which of the following forms phosphodiester bonds by sealing nicks in the DNA sugar phosphate backbone?

ligase

Sickle cell anemia is a genetic disorder that causes red blood cells to take on an abnormal, crescent shape. This inherited disorder is the result of a single base change from A to T. This changes the amino acid glutamic acid to valine at position six of the hemoglobin protein. Based on this information, sickle cell anemia results from a(n) ________ mutation.

substitution mutation

The rabies virus primarily affects the nervous system. The specificity that the rabies virus has for neuronal host cells is primarily dictated by __________________________.

the spikes that protrude from its viral envelope

Chloroflexus aurantiacus is a photoautotrophic bacterium that grows in hot springs. Which of the following serves as an energy source for C. aurantiacus?

the sun

Which of the following are bacteria that initially had a cell wall and lost it either through the course of their life cycle or due to mutation?

L-form bacteria

Lactate dehydrogenase converts lactate to pyruvic acid. In this reaction the enzyme also converts NAD+ to NADH. Choose the statement that best describes lactate dehydrogenase's actions.

Lactate dehydrogenase reduces NAD+ to NADH and oxidizes lactate to pyruvic acid.

Of the following enzymes, which are correctly matched with their function?

Ligase, covalently bonds adjacent Okazaki fragments DNA polymerase III, builds most of the DNA on the leading and lagging strand

CIDEX is an activated glutaraldehyde solution used to kill microbial cells on medical instruments. Which of the following terms best describes CIDEX?

Microbiocidal disinfectant

Oncogenic viruses, such as certain human papillomaviruses (HPVs) cause cancers. What is the most likely mechanism that certain HPVs use to promote cancer?

Oncogenic viruses, such as certain human papillomaviruses (HPVs) cause cancers. What is the most likely mechanism that certain HPVs use to promote cancer?

Which of the following pathways would you expect to be the most active when a cell has an insufficient amount of ATP?

Oxidation of acetyl-coA through the Krebs cycle

Choose the true statement about post-translational modifications.

Post-translational modifications include phosphorylation, trimming, and addition of organic factors.

Which of the following is NOT one of the domains of life?

Prokaryote are Bacteria Archaea Eukarya

Select the false statement about the differences between eukaryotes and prokaryotes.

Prokaryotic cells can exhibit both asexual and sexual reproduction, whereas eukaryotes only carry out asexual reproduction. True Eukaryotes have a defined nucleus and other membrane bound organelles, while prokaryotes lack a nucleus. Prokaryotes only include unicellular archaea and bacteria. Most prokaryotes have a single circular chromosome, as compared to a eukaryote's larger genome spread across multiple linear chromosomes.

Choose the true statement(s) about protists.

Protists can be photosynthetic or heterotrophic. The term protozoan describes animal-like protists but is not a true taxonomic ranking.

Which of the following microbial temperature classifications is improperly matched with its potential growth environment?

Psychrotroph - arctic lake sediment

Choose the true statement(s) regarding quorum sensing.

Quorum sensing is an example of pre-transcriptional gene regulation. Quorum sensing is a population-based form of gene expression regulation. Quorum sensing relies on the production of autoinducers.

Choose the correct statement about viral evolution.

RNA viruses mutate faster than DNA viruses due to a lack of proofreading replicative enzymes.

Retroviruses, such as human immunodeficiency virus, rely on reverse transcriptase to multiply inside a cell. However, HIV also requires host ribosomes to build new viral particles. Based on your knowledge of the central dogma, order the flow of genetic information from left-to-right, from the first step (left) to the last step (right), for retroviruses.

RNA, DNA, RNA, Protein

How do retrotransposons differ from DNA transposons?

Retrotransposons rely on reverse transcriptase for transposition, while DNA transposons do not.

How are ribozymes different from enzymes?

Ribozymes are made of ribonucleic acid, whereas enzymes are made of protein.

You suspect that your patient has a urinary tract infection caused by Proteus vulgaris, a motile bacterium with peritrichous flagella. Which of the following physical states of media is best for observing motility of this pathogen once isolated?

Semisolid deep

Choose the true statement about the Krebs cycle.

The major energy benefit of the Krebs cycle is the mass production of reduced cofactors, such as NADH and FADH2.

Which of the following are ways that viruses differ from prokaryotes and eukaryotes?

Unlike prokaryotes and eukaryotes, viruses are incapable of replicating independently from a host cell. Unlike prokaryotes and eukaryotes, viruses are classified as acellular particles. Unlike prokaryotes and eukaryotes, viruses are not considered alive.

Which of the following is a protein shell that packages and protects the genome and accounts for the bulk of a virion mass?

capsid

Which intracellular structure is responsible for forming the fibrous proteins that build one part of the cytoskeleton?

centrosome

Cells that can be transformed are known as

competent

What are the components of a nucleotide?

A sugar Phosphate Nitrogen base

Which of the following is one way that enzymes decrease activation energy?

Enzymes stabilize the reaction's transition state.

Choose the true statement about the genetic code.

The genetic code is redundant, with multiple codons specifying a single amino acid.

What observations could you make in the case of a positive catalase test?

You may see bubbles develop upon adding hydrogen peroxide to the sample.

What organisms like to live inside the human body?

mesophiles

Which grouping of parasitic helminths includes hookworms?

roundworms

Choose the true statement about pre-transcriptional regulation.

This form of regulation controls when and how often RNA is produced from a DNA template.

Which of the following is an example of a post-transcriptional regulation mechanism?

riboswitches

Which phase of bacterial growth is often used to produce useful substances for humans?

stationary phase

Which genome characteristic is NOT one of prokaryotic cells?

DNA is located in the nucleus are histone-like proteins one chromosome binary fission plasmids can be taken in from the surrounding environment

Choose the true statement about anabolic reactions.

Anabolic reactions tend to be endergonic

Choose the false statement about cellular transport mechanisms.

Diffusion is the passive movement of substances from areas of low concentration to areas of high concentration. True Facilitated diffusion does not require energy and uses membrane proteins to move substances down their concentration gradient. Active transport requires energy and uses carrier proteins to move substances against their concentration gradient. Osmosis is the passive movement of water from a low-solute concentration to a high-solute concentration.

Fluoride and triclosan are compounds that inhibit the oral pathogen Streptococcus mutans, which can cause dental caries (cavities). These compounds inhibit pyruvate kinase, an enzyme that uses substrate level phosphorylation to convert phosphoenolpyruvate to pyruvic acid and ATP. Based on your knowledge of cellular respiration, fluoride and triclosan specifically prevent the final step in which metabolic pathway?

Glycolysis

The _______ resembles a series of flat sacs called cisternae. This organelle modifies, builds, sorts, and distributes products to the cell membrane to be secreted.

Golgi apparatus

While hiking, your patient was bitten by a rabid raccoon. Your patient denies having any previous rabies vaccinations. Which of the following antiviral medications should be administered to your patient to prevent viral attachment to host cells?

HRIG

Your elderly patient is affected by shingles. After careful observation, you note that the virus responsible for the infection has an icosahedral capsid, is enveloped, and has double-stranded linear DNA as its genetic material. Based on this information, in which of the following viral families would you group this viral pathogen?

Herpesviridae

Choose the true statement about Hfr strains.

Hfr strains result when the fertility plasmid integrates into the host chromosome.

Choose the true statement about housekeeping genes in Escherichia coli.

Housekeeping genes are constitutively expressed.

Your patient has purple, red, and brown lesions on the legs, indicative of Kaposi sarcoma. Given this observation, which of the following oncogenic viruses is most likely present in your patient?

Human herpes virus-8

A young patient who underwent surgical placement of depth electrodes for epilepsy treatment contracted a prion disease. Cortical electrode probes are known to be reused in patients. Based on this information, which of the following prion diseases did the young patient most likely contract?

Iatrogenic Creutzfeldt-Jakob Disease

Which of the following is an example of phage conversion?

Infection of Streptococcus pyogenes with T12 phage enables the bacteria to produce erythrogenic toxins, allowing it to cause scarlet fever.

You wish to culture and quantify T4 bacteriophages. Which of the following techniques would be the most relevant?

Perform a plaque assay using the bacterium Escherichia coli.

Choose the true statement(s) regarding phosphodiester bonds.

Phosphodiester bonds are what hold the "sugar-phosphate" backbone of DNA together Phosphodiester bonds are created by linking the 3' hydroxyl group to the 5' phosphate of an adjacent nucleotide.

Choose the true statement(s) about prokaryotic external appendages. To be marked correct, you'll need to select all true statements, as there may be more than one correct answer.

Pili allow for adhesion, movement, and aid in gene transfer through conjugation. Flagella allow for motility. The glycocalyx promotes adhesion and interferes with phagocytosis.

Select the true statement regarding the Entner-Doudoroff Pathway.

The Entner-Doudoroff pathway produces NADPH, an important reducing agent in anabolic reactions.

Your patient has a suspected case of gas gangrene, which is caused by the obligate anaerobe Clostridium perfringens. Which of the following considerations should be made when culturing this organism?

The clinical specimen should be placed inside a small anaerobic jar or chamber during incubation. The clinical specimen should be quickly deposited and capped in a vial with a reducing agent.

The generation time for Escherichia coli inside of the human intestinal tract has been estimated at 12 hours. However, when grown in Luria Bertani medium as a pure culture under standard laboratory conditions, the generation time for E. coli is 20 minutes. Which of the following accounts for this discrepancy in generation time?

The human intestinal tract contains other microbes, which compete for limited nutrients.

Choose the true statement about protein synthesis.

The first amino acid in a eukaryotic protein sequence is methionine, whereas the first amino acid in a prokaryotic protein sequence is formyl methionine.

Choose the true statement(s).

The four kingdoms of eukaryotes include Animalia, Plantae, Fungi, and Protista. The four kingdoms of eukaryotes each include members that may conduct sexual and/or asexual reproduction. Kingdom Fungi includes unicellular and multicellular organisms.

Choose the false statement about the cell's nucleus.

The nucleus contains a region called the nucleolus, where DNA is copied. True Unless the cell is dividing, the DNA of the nucleus is loosely organized as chromatin. The nucleus is typically visible with a light microscope. The nucleus has a membrane that gives rise to the endoplasmic reticulum.

You need to collect a specimen from a patient who you suspect has strep throat. Which of the following considerations should be made when collecting this clinical specimen?

The specimen should be quickly transported to the laboratory. The specimen should be collected using aseptic techniques.

What are inclusion bodies?

They're distinct collections of substanced inside prokaryotic cells.

Which protozoans contain pseudopods?

amoeboid protozoans

Cells can only make ____________ amino acids on their own.

nonessential

Prokaryotic cells house a single circular chromosome in their __________.

nucleoid region

_____________________ is a process that uses energy from nutrients to fuel an electron transport chain to make ATP.

oxidative phosphorylation