Microbiology Review Flashcards

Flashcards generated from lecture notes to review key microbiology concepts.

What is the general definition of a microbe?

A living organism that requires a microscope to be seen, ranging in size from millimeters (mm) to micrometer (um).

Give some examples of exceptions to the general definition of a microbe.

Supersize microbial cells, microbial communities such as pathogens, and viruses.

What is a key characteristic of viruses that makes them an exception to the microbe definition?

They are acellular, nonliving microorganisms.

Who built the first compound microscope and coined the term 'cell'?

Robert Hooke

Who was the first to observe single-celled microbes?

Anton Van Leeuwenhoek

Who introduced smallpox variolation to the American colonies?

Mr. Onesimus

Who introduced smallpox variolation to Europe?

Lady Montagu

Who developed the first vaccine?

Edward Jenner (using cowpox to prevent smallpox)

Who disproved spontaneous generation?

Louis Pasteur

What scientific method of microbiology did Robert Koch found?

The scientific method of microbiology, including Koch's postulates.

What are Koch's postulates used for?

To determine that many diseases are caused by microbes

Who discovered that Penicillium mold inhibited Staphylococcus aureus growth?

Alexander Fleming

Who discovered lithotropes and enrichment cultures?

Sergei Winogradsky

Who proposed the endosymbiotic theory?

Lynn Margulis

Which scientist discovered that prokaryotes can differentiate through their ribosomes and survive in extreme environments and grouped the three domains of life?

Carl Woese

What are the three domains of life?

Bacteria, Archaea, and Eukarya

What is a key component in the cell wall of bacteria?

Peptidoglycan

Do archaea have peptidoglycan in their cell walls?

No

What are the differences between brightfield and darkfield microscopy?

Brightfield microscopy produces a dark image over a light background, while darkfield microscopy produces images of living, unstained cells as halos of light against a dark background.

What is the purpose of phase contrast microscopy?

Used to reveal motility and shape of living cells; refracted and transmitted light shifted out of phase.

What does TEM allow you to see?

INSIDE the specimen as electrons pass through it

What does SEM allow you to see?

Electrons scan the surface of a specimen, generating a 3D image

How do you calculate total magnification in light microscopy?

Ocular lens power x objective lens power

What is the role of oil immersion in microscopy?

To gather as much light as possible when using the 100x objective, creating a clearer image.

What shape are bacilli?

Rods

What shape are cocci?

Spherical/circular

What is the primary stain used in Gram staining?

Crystal Violet

What color do Gram-positive bacteria appear after Gram staining?

Purple

What is the role of Gram's iodine in Gram staining?

To bind the dye to the cell wall of the organisms

What is the purpose of ethanol in Gram staining?

Decolorizer to remove loosely trapped stain (typically from Gram Negative bacteria)

What is the counterstain used in Gram staining?

Safranin

What color do Gram-negative bacteria appear after Gram staining?

Pink

What is the difference between the cell walls of bacteria and archaea?

Bacteria mostly have peptidoglycan in cell walls, while Archaea do not.

What is a unique characteristic of archaeal membrane lipids?

Fatty acids connected by ether bonds, making them harder to break

What are the differences between the cell walls of Gram-positive and Gram-negative bacteria?

Gram-positive bacteria have a thick layer of peptidoglycan in their cell wall, while Gram-negative bacteria have a thin layer.

Why is an acid-fast stain used for Mycobacterium instead of a Gram stain?

Mycobacterium has an acid-fast cell wall rich with mycolic acid.

What is the function of the cell membrane?

Encloses the cytoplasm

What is peptidoglycan made of?

Alternating NAG and NAM

What is found inside the cytoplasm?

Cytosol.

What is the site of protein synthesis

Ribosomes

What is the Nucleoid?

Contains the cells chromosomes; genetic material of the cell

What is an episome?

When Plasmids are integrated into the genome and replicated as part of the chromosomes

What does FtsZ do?

A protein that forms a ring around the equator of the cell, splitting it for cell replication

What are pili used for?

Attachment and twitching motility

What are fimbriae used for?

Attachment and biofilm formation

What does monotrichous mean?

Cells have a single flagella

What does amphitrichous mean?

cells have a single flagella and both ends

What does lophotrichous mean?

cells have several flagella at one or both ends

What does peritrichous mean?

have flagella randomly distributed around the cell

What is binary fission?

Asexual reproduction by a separation of the body into two new bodies

What is twitching motility?

short intermittent jerky movements

What it bacterial gliding motility?

Creeping along a solid surface

What the difference between heterotroph and autotroph?

Auto makes own carbon source; Hetero breaks down glucose for carbon

What the difference between phototroph and chemotroph?

Photo absorbs light for energy; Chemo gets energy from chemical electron donors

What the difference between lithotroph and organotroph?

Litho gets electrons from inorganic molecules; Organo gets electrons from organic molecules

What pH does acidphiles thrive?

Low pH

What is a neutophile?

Grow at a neutral pH

What is a Alkaliphile?

Loves High pH

What temp do psychrophiles thrive?

Low Temps (0-20 C)

What is the optimal temperature for mesophiles?

Room temperature (20-45 C)

What is the optimal temperature for thermophiles?

Elevated temperature (45-85 C)

What is a obligate aerobe?

Requires oxygen for growth.

What is an obligate anaerobe?

Killed in presence of oxygen

What the grows best in an environment with O2 lower than atmospheric?

Microaerophile

What the difference between barotolerant, barophillic , and barosensitive?

Barotolerant tolerate pressure; Barophillic maximum growth at high pressure; Barosensitive Die when pressure increases.

What happens during the lag phase of growth?

Cells are synthesizing, “gearing up for growth”

What is the Exponential Phase?

Also know as log phase, maximal rate of growth and division, population is uniform in terms of chemical and physical properties

What is the limiting factor in stationary phase?

resources are always the limiting factor for growth, population growth ceases, reproduction and death rate are balances

What is being built up in the death phase that causes exponential cell death?

toxic wasters

What are the end products of glycolysis?

2 pyruvate, 2 ATP, 2 NADH

What are the end products of PP?

Sugars and 2 NADPH

What are the end products of PDC?

NADH, CO2

What are the end products of the TCA cycle?

2 CO2, 3 NADH, 1 FADH, 1 ATP

What does ETS use to transport electrons?

NADH and FADH2

End product difference between aerobic and anerobic respiration

Anaerobic produces less atp compared to aerobic.

What does homolactic fermentation produce?

two molecules of lactic acid

What is the difference between secretion and translocation?

Translocation is movement of proteins from cytoplasm to plasma membrane or periplasmic space; Secretion is movement of proteins from cytoplasm to external environment

What are the stop codons?

UGA, UAG, UAA

What is wobble?

The third codon is typically less important than the first two when encoding for an amino acid

What is inducible transcription regulation?

something is off, turns it on

What is repressible transcription regulation?

smething is on, turns it off

What is Quorum sensing?

Cell to cell communication meditated by AHL

What the difference between point mutations: Missense, Nonsense, Silent

Missense: change in DNA causes a different amino acid;

Silent: change in DNA but not amino acid;

Nonsense: AA is replaced with a stop codon

What does the polymerase chain reation product?

Produces million-fold copies of the same target DNA within a few hours

What is the mechanism of action of penicillins?

Inhibit cell wall synthesis by blocking transpeptidation

What is MIC?

minimal inhibitory concentration- lowest concentration of a drug that prevents growth of the pathogen

What is MLC?

Minimal Leathal Concentration (MLC)- lowest concentration of drug that kills the pathogen

What is bactericidal?

kills the target pathogen

What is bacteriostatic?

inhibits the growth of microbes

How is Kirby-Bauer interpreted?

Tests the sensitivity/ resistance of multiple antibiotics, through measuring the DIAMETER of the zone of inhibition

What does multidrug resistance mean?

Resistant to multiple drugs

What is the job of B- cells?

Produce antibodies for humoral response, destroying pathogens

What is the helper T- cell marker?

CD 4+

What does cytoxic T- cells do?

destroy infected cells

What is Neutralization?

inactivating toxins or blocking pathogen attachment

What is opsonization

coating pathogens to enhance phagocytosis

What does the microbiome aid in?

digestion, modulates the immune system, and prevents pathogen colonization

What is the most common bacteria on skin?

Gram Positive bacteria (Staphylococcus epidermis and Propionibacterium acnes)

What pathogen cause of UTIs?

Enterobacteria

What does Probiotics do?

Living organisms ingested to restore natural microbial balance