Microbiology Exam 2 Review Flashcards

Flashcards covering fungal morphology, pathogenic microbes, viral replication, bacterial growth, and molecular genetics based on lecture review notes.

Mycelium

A tangle of fungal hyphae or a mass of filaments typically found in molds.

Fungal Locomotion

Fungi are generally not capable of locomotion through the use of flagella.

Naegleria fowleri (Water)

Microbe that swims through water as a flagellated form.

Naegleria fowleri (Human)

Once in a human host, this organism assumes an amoeboid form.

Primary amebic meningoencephalitis

A brain-eating disease caused by the microbe Naegleria fowleri.

Naegleria fowleri (Adverse conditions)

Forms a cyst under adverse environmental conditions.

Dimorphism

The ability of pathogenic fungi to grow as either yeast or mold.

Cestodes (Tapeworms)

Multicellular parasites that have a scolex for attaching to the host's intestine.

Fungal Spores

A major cause of asthma in humans.

Hypersensitivity

One of the three ways fungi cause illness, characterized by an allergic reaction to fungal components.

Intoxication

A way fungi cause illness where the fungus produces a toxin that is then ingested.

Mycosis

An infection where fungus grows on the body.

Basidiomycota sexual spores

Referred to as Basidiospores.

Fungal Morphology Terms

The terms yeast, mold, and mushrooms refer to these physical characteristics.

Mucoromycota sexual spores

Referred to as Zygospores.

Fungi Classification

Fungi are categorized according to their method of sexual reproduction.

Fungi Habitats

Found in nearly every habitat on Earth, including environments that are very hot, very cold, or have high salt concentrations.

Protozoan Food Chain Role

They ingest large numbers of bacteria and algae.

Malaria Cause

Caused by a protozoan microbe.

Leishmaniasis Transmission

Transmitted to humans by sandflies.

Toxoplasmosis Prevention

Involves avoiding the consumption of inadequately cooked meat.

Entamoeba histolytica

Microbe that causes amebiasis and produces cysts that survive stomach passage.

Schistosomiasis

A disease caused by the blood fluke.

Chitin

The material found in the cell walls of fungi.

Protozoan Life Stages

Many species have the ability to exist as either a trophozoite or a cyst.

Subcutaneous Fungi

Fungi that specifically infect the deeper layers of the skin.

Intestinal Protozoan spread

Infections are typically spread by the fecal-oral route.

Helminth Modes of Entry

Includes transmission via insect bites, ingestion with food or water, and burrowing through the skin.

Definitive Host

An organism in which sexual reproduction or the adult form of a parasite occurs.

African Sleeping Sickness Vector

Transmitted by tsetse flies.

Toxoplasmosis (Healthy individuals)

In otherwise healthy people, the disease is brought under control by the immune system.

Proglottids

Tapeworm segments that contain either male or female reproductive structures.

Tapeworm Nutrition

They lack a digestive system and absorb nutrients across their body surface from the host.

Tapeworm Definitive Hosts

Include organisms such as cattle, fish, or pigs.

Extracellular Viruses

Outside of living cells, viruses are considered metabolically inert.

Helical, Icosahedral, and Complex

Terms that refer to the various shapes of viruses.

Lytic Phage

A virus that replicates inside the host cell and then lyses its host during its release.

Lysogenic Cell

A cell containing viral DNA (a prophage) integrated into the host chromosome.

Persistent Infection

An infection in which the virus is continually present in the body.

Bacteriophage Attachment (Entry)

The step where only the nucleic acid enters through the host cell wall.

Lytic Replication Sequence

Attachment, Entry, Synthesis, Assembly, and Release.

Capsid

The protein coat of a virus that protects the nucleic acid.

Capsid Recognition function

In non-enveloped viruses, it is involved in the recognition of host cell receptors.

Viral Host Range

Depends on the presence of host receptor molecules on the cell.

Replicase

An RNA-dependent RNA polymerase required for the replication of ($-$)ssRNA and ($+$)ssRNA viruses.

Enveloped Viruses

Viruses that have a lipid bilayer membrane containing various proteins.

Prion Protein Accumulation

Process where abnormal prion proteins change normal prion proteins into the abnormal form.

Phage DNA Integration

Occurs when a phage synthesizes an enzyme that integrates its DNA into the host's chromosome.

Viral Envelope Acquisition

This occurs during the release step of viral replication.

Viroids

Infectious agents that cause disease in plants.

Bacteriophages

Viruses that specifically infect bacteria.

Spikes

Protein projections on the surface of a virus involved in attachment to host cells.

Targeting step (Animal viruses)

A replication step involving the nucleus of a eukaryotic cell.

Prions

Infectious proteins.

Normal Prion Protein

Proteins that are susceptible to protease digestion.

Abnormal Prion Protein

Proteins that are resistant to protease digestion and accumulate in cells.

Segmented Virus

Refers to viruses that may contain several pieces of RNA.

Lag Phase

Growth phase where cells are preparing for, but have not begun, cell division.

Aerotolerant Anaerobes

Organisms that are indifferent to oxygen and do not use it.

Agar

The most successfully used solidifying agent in bacterial nutrient media.

Lag Phase Metabolic Activity

Phase characterized by metabolically active cells preparing for multiplication.

Exponential (Log) Phase

The phase in the growth curve where bacteria are rapidly increasing in number.

Death Phase

Phase of the bacterial growth curve during which the total number of viable cells declines.

Streak-Plate Method Purpose

Used to generate isolated colonies for pure culture.

Logarithmic growth

The manner in which cell numbers increase in a rapidly multiplying bacterial population.

Halophile

An organism that requires high salt concentrations for growth.

Superoxide Dismutase and Catalase

Enzymes that deal with toxic oxygen-containing molecules.

Photoautotroph Energy

Organism that makes use of light for energy purposes.

Bacterial Isolation (Simplest)

The streak-plate method.

Selective Medium

A medium that inhibits the growth of organisms other than the one being sought.

Strict Anaerobes (Superoxide dismutase)

Strictly anaerobic organisms generally lack this enzyme.

MacConkey agar

A medium that is both selective and differential.

DNA hydrogen bonds

The bonding method that holds the two strands of DNA together.

Incorrect DNA pairing

An example pairing of $T:U$.

$3'$ end of DNA

Has a hydroxyl group attached to the number $3$ carbon of deoxyribose.

Leading Strand Synthesis

A feature described as continuous replication.

$$3' AGGCUAAC 5'$$

Sequence that is complementary to $5' TCCGATTG 3'$.

Origin of Replication

The specific site where DNA replication begins.

DNA Nucleotide Addition

Nucleotides are added to the $3'$ end of the growing strand.

Semiconservative replication

Replication where molecules contain one original and one new strand.

Bidirectional replication

Refers to replication starting at an origin and proceeding in two directions.

Antiparallel

Refers to the opposite orientation of the two strands in DNA.

Codon

A sequence of $3$ nucleotides.

tRNA

The molecule that carries an anticodon.

AUG

A codon that codes for methionine and determines the reading frame.

Genetic Code Universality

The genetic code is nearly universal across organisms.

Stop Codon

A codon that codes for no amino acid and stops translation.

Stop Codon Examples

Includes $UAA$, $UAG$, and $UGA$.

Bacterial First Amino Acid

Methionine is the first amino acid placed during translation.

P-site

The peptidyl site on the ribosome.

E-site

The site on the ribosome responsible for the release of tRNA.

Repressible Enzyme

An enzyme that is normally on but can be turned off.

Operon

A group of genes in bacteria controlled in a coordinated manner involving polycistronic mRNA.

tRNA anticodon

The component that determines which amino acid is linked to a specific tRNA.

Ribosome Movement

Ribosomes move along the mRNA in a $5'-3'$ direction.

Adenine and Thymine bonds

Adenine binds to thymine via two hydrogen bonds.

DNA replication direction

DNA replication is usually bidirectional.

Quorum Sensing

The production and monitoring of signaling molecules to sense cell density in a population.

Mutation

The source of variation among microorganisms.

Transposons

Segments of DNA capable of moving from one region in the DNA to another.