Microbiology Final Exam Flashcards

Flashcards for Microbiology Final Exam Review

Describe the cellular morphologies of single-cellular vs multicellular microorganisms.

Yeasts and some fungi are single-celled, while molds, multicellular fungi (like mushrooms), and helminths are multicellular.

Differentiate between prokaryotic and eukaryotic microorganisms.

Bacteria and archaea are prokaryotic, possessing no nucleus. Protists (algae & protozoa), fungi (yeasts & molds), and helminths are eukaryotic, containing a nucleus.

Compare the cell wall composition of bacteria and archaea.

Bacterial cell walls are made of peptidoglycan, while archaeal cell walls contain pseudopeptidoglycan.

List common shapes of bacteria.

Coccus, bacillus, spirochete, and vibrio.

Contrast the peptidoglycan layer thickness in Gram-positive and Gram-negative bacteria.

Gram-positive bacteria: thick peptidoglycan layer (30-100 nm). Gram-negative bacteria: thin peptidoglycan layer (no more than 4 nm).

What is unique about the cell structure of Mycoplasma pneumoniae and how does this affect its antibiotic resistance?

It lacks a cell wall, making it inherently resistant to antibiotics that target cell wall synthesis.

What is unique about the cell walls of Mycobacterium species? How does this affect its resistance against antibiotics?

The thick waxy layer, rich in mycolic acids, makes their cell walls highly hydrophobic and significantly contributes to their resistance against antibiotics by limiting the permeability of drugs into the cell.

Which type of bacteria is pink at the end of Gram staining?

Gram-negative

Which type of bacteria is purple at the end of Gram staining?

Gram-positive

What is the target of Penicillins and Cephalosporins?

Penicillin-binding proteins.

What is the target of Isoniazid?

Mycobacterium (M. tuberculosis).

Describe key characteristics of Diplomonadida species (Giardia).

Have two identical nuclei, lack mitochondria but have mitosomes, are flagellated, form cysts, and exist as trophozoites in the host.

Describe key characteristics of Kinetoplastids (Trypanosoma).

Have single large mitochondria, attached flagella, and include Trypanosoma cruzi, which causes Chagas’ disease.

Describe key characteristics of Ciliates (Balantidium coli).

Have cilia and some have a macronucleus and a micronucleus.

Describe key characteristics of Amoebae (Entamoeba).

Move using pseudopodia, form chitin-shelled cysts, and include Entamoeba, a leading cause of death from parasitic disease.

Describe Cestodes (tapeworms).

Flat, segmented, ribbon-shaped hermaphroditic worms (tapeworms).

Describe Nematodes (roundworms).

Long, thin, unsegmented helminths with a complete digestive system, transmitted through the fecal-oral route.

Describe Trematodes (flukes).

Non-segmented flatworms with at least one sucker, life cycle occurs in at least two different hosts.

Describe Histoplasmosis and its pathology, plus the symptoms.

Includes fever, headache, weakness, and chest discomfort; caused by inhaling spores, transitions from mold to yeast at 37 degrees Celsius.

Describe the relationship between microbiota and candidiasis

Candidiasis is caused by opportunistic yeast infections by Candida albicans.

During which phase of bacterial growth are antibiotics most effective?

Log phase (exponential phase).

During which phase are antibiotics usually produced?

Stationary phase.

During which phase would endospores be produced?

Stationary phase, when nutrients become limited and environmental conditions become less favorable.

Give an example of a disinfectant and an antiseptic.

Bleach is a disinfectant, Betadine is an antiseptic.

Give an example of a use for a halogen.

Chlorination of pools, using Betadine to prepare a patient for surgery, and fluoride in toothpaste.

Give an example of a use for a peroxygen.

Using hydrogen peroxide on a cut.

Give an example of a use for a phenolic compound.

Cleaning your floor with pine oil.

Give an example of a use for a heavy metal.

Applying silver nitrate burn cream.

Give an example of a use for a surfactant.

Washing your hands with soap.

Give an example of a use for an alcohol.

Isopropanol on skin prior to an injection.

Give an example of a use for nonionizing radiation.

UV lights in hospital rooms.

Give an example of a use for ionizing radiation.

Gamma sterilization for strawberries.

Define metabolism.

All of the chemical reactions in the cell is metabolism.

Define catabolism.

Breaking down macromolecules is catabolism.

Define anabolism.

Building new macromolecules is anabolism.

Define oxidation.

Oxidations - electrons are lost from donor molecules.

Define reduction.

Reductions - electrons are gained by acceptor molecules.

Identify the function of an enzyme.

Enzymes reduce activation energy by bringing reactant molecules close together and putting strain on bonds.

Which of the following are products of glycolysis?

2NADH & 2 pyruvate.

Ethanol and CO2 are the end products of which process

alcohol fermentation.

Explain the meaning of the central dogma of molecular biology.

The central dogma states that DNA encodes messenger RNA, which, in turn, encodes a protein.

Which antibiotic inhibits the activity of DNA gyrase & blocks DNA replication, killing the cell?

Fluoroquinolones.

What is the mechanism of action of macrolides?

Bind to the 50s ribosomal subunit, prevent peptide bond formation, & stop protein synthesis.

What is the mechanism of action of aminoglycosides?

Bind to the 30s ribosomal subunit & impair proofreading, resulting in production of faulty proteins.

Which part of the body is affected most by diseases caused by prions?

The brain tissue.

What allows for antibiotic resistance genes to become prevalent in the population?

Natural selection.

Which type of horizontal gene transfer requires cell to cell contact using a pilus?

Conjugation.

What is ID50?

The number of microbes required to cause active infection in 50% of inoculated animals.

What is LD50?

The number of microbes required to kill 50% of infected animals.

Give the names for the two type of adaptive immuntiy

Cell-mediated- T cells: directly attack other cells (cellular immunity). Humoral- B cells which release antibodies (humoral immunity).

Iodophors are an example of which type of disinfectant class?

halogens!!

What is the mode of action of isoniazid?

inhibit the production of mycolic acid!!

Which autoimmune disease results in the overstimulation of the thyroid?

graves disease

How are microbiota and candidiasis connected?

Candidiasis is caused by an opportunistic pathogen when the microbiota is depleted

Which species of which genus causes malaria?

plasmodium

A gram stain works because of differences in which cellular structure?

cell wall