Microbiology 150

What are the three domains of life?

Archaea, Bacteria, and Eukarya

Which domains contain prokaryotic organisms?

Archaea and Bacteria

Which domain contains eukaryotic organisms?

Eukarya

What is the main difference between prokaryotic and eukaryotic cells?

Prokaryotic cells lack a nucleus.

What is the standard reference for identifying and classifying prokaryotes?

Bergey’s Manuals.

What is the study of evolutionary relationships called?

Phylogeny.

What are the two names in binomial nomenclature?

Genus and species.

How did Woese and Fox classify organisms?

Using rRNA.

What is the basis of the Baltimore classification system?

Viral genomes (DNA or RNA, single or double-stranded).

What is a phylogenetic tree?

A diagram showing evolutionary relationships.

What is the traditional concept of species not readily applicable to microbes?

Asexual reproduction and horizontal gene transfer.

What is the main component of bacterial cell walls?

Peptidoglycan.

Do all bacteria have cell walls?

Most do, but not all.

What is a structure found in eukaryotic cells but not prokaryotic cells?

Nucleus.

What are plasmids?

Small, circular pieces of DNA in prokaryotes.

What are the functions of the cell membrane?

Barrier and control of transport.

Name one external structure of a prokaryotic cell.

Flagella or pili.

What are the internal structures of eukaryotic cells?

Organelles.

What is the function of a ribosome?

Protein synthesis.

What is the function of the mitochondria?

ATP production.

What is the function of the chloroplast?

Photosynthesis.

What is a capsule?

A structure that aids in immune evasion.

What is the function of fimbriae?

Attachment.

What is the central dogma of molecular biology?

DNA -> RNA -> protein.

What is the process of DNA replication?

Copying DNA.

What is transcription?

Making RNA from DNA.

What is translation?

Making protein from RNA.

What is a mutation?

A change in DNA sequence.

What is an operon?

A cluster of genes regulated together.

What is a plasmid?

A small circular piece of DNA.

What is horizontal gene transfer?

Transfer of genes between cells.

What is a point mutation?

Change in a single base.

What is a frameshift mutation?

Insertion or deletion that changes reading frame.

What is a silent mutation?

Mutation that does not change the amino acid sequence.

What is a missense mutation?

Mutation that changes the amino acid.

What is a nonsense mutation?

Mutation that results in a stop codon.

What enzyme is used to make cDNA?

Reverse transcriptase.

What are viruses composed of?

Proteins and genetic material (DNA or RNA).

What are the basic shapes of viral capsids?

Helical, polyhedral, and complex.

What is a bacteriophage?

A virus that infects bacteria.

What is a virion?

An individual virus particle.

Are viruses cellular or acellular?

Acellular.

What is the lytic cycle?

Viral replication that lyses the host cell.

What is the lysogenic cycle?

Viral replication where the viral DNA is incorporated into the host DNA.

What is reverse transcriptase?

An enzyme used by retroviruses to convert RNA to DNA.

What is a retrovirus?

A virus with an RNA genome that uses reverse transcriptase.

What is a latent viral infection?

A virus remains dormant in the host.

What is an enveloped virus?

A virus with a lipid membrane surrounding the capsid.

What are spikes on viruses?

Proteins that aid in attachment to host cells.

What are the main components of the viral life cycle?

Attachment, penetration, biosynthesis, maturation, and release.

What is transduction?

Transfer of genes by a virus.

What is a plaque?

A clear area on a bacterial lawn caused by viral lysis.

How are viral diseases classified?

Using ICD codes.

What are cytopathic effects?

Cell abnormalities caused by viral infection.

What is a filterable agent?

Viruses were originally described as filterable agents.

What is a common method for cultivating viruses?

Using tissue culture or embryonated eggs.

What is a pure culture?

A culture containing only one species.

What is agar?

A solidifying agent in culture media.

What are the two main types of light microscopes?

Brightfield and electron microscopes.

What is a simple stain?

Using one dye to stain the specimen.

What is a differential stain?

Using more than one dye to stain different structures.

What is the Gram stain?

A differential stain to distinguish between Gram-positive and Gram-negative bacteria.

What color do gram-positive bacteria stain?

Purple.

What color do gram-negative bacteria stain?

Pink.

What is a mordant?

A substance that fixes a stain.

What is a counterstain?

A stain used after the primary stain.

What is fluorescence microscopy?

Using fluorochromes to illuminate specimens.

What is an electron microscope used for?

Observing small objects like viruses.

What is the purpose of a condenser lens?

To focus light on the specimen.

What is the purpose of immersion oil?

To improve resolution at high magnification.

What is a biochemical test?

A test to identify microbes based on their metabolic properties.

What is a serological test?

Test using antibodies to identify a specific microbe.

What is selective media?

Media used to inhibit growth of unwanted microbes.

What is differential media?

Media used to distinguish between microbes.

What is defined media?

Media with a known chemical composition.

What is complex media?

Media with an unknown chemical composition.

What is an inoculation loop?

A tool used to transfer microorganisms.

What is a Bunsen burner?

A tool used to sterilize equipment.

What is a colony?

A visible population of microbes grown from a single cell.

What is a spectrophotometer?

A tool to measure turbidity of microbial growth.

What is binary fission?

How bacteria reproduce by simple cell division.

What is generation time?

Doubling time of a bacterial population.

What is a growth curve?

A graph showing bacterial population growth over time.

What are the phases of a bacterial growth curve?

Lag, log, stationary, and death.

What are biofilms?

Microbial communities encased in a matrix.

What is quorum sensing?

Cell-to-cell communication in bacteria.

What are the different oxygen requirements of microbes?

Aerobes, anaerobes, facultative anaerobes, microaerophiles.

What is an obligate aerobe?

A microbe that requires oxygen.

What is an obligate anaerobe?

A microbe that cannot tolerate oxygen.

What is a facultative anaerobe?

A microbe that can grow with or without oxygen.

What is a microaerophile?

A microbe that requires a small amount of oxygen.

What is the effect of pH on microbial growth?

Influences enzyme activity.

What are psychrophiles?

Microbes that grow best in cold temperatures.

What are mesophiles?

Microbes that grow best in moderate temperatures.

What are thermophiles?

Microbes that grow best in hot temperatures.

What are halophiles?

Microbes that require high salt concentrations.

What are barophiles?

Microbes that grow under high pressure.

What are some methods of sterilization?

Autoclaving, filtration, radiation.

What is disinfection?

Removing pathogens from fomites.

What is degerming?

Removing microbes from a surface by scrubbing.