BIOL 2320 Lecture Test I Review: Wright

300 Q&A flashcards covering key microbiology concepts from the provided notes.

What is the Miasma Hypothesis?

Ancient belief that bad air causes diseases.

Who is considered the father of Western medicine who believed diseases came from the environment?

Hippocrates.

Who first observed microorganisms (bacteria and protist) using lenses to see cells? first microscope

Antonie van Leeuwenhoek.

What did Robert Koch prove?

Specific microbes cause specific infections; he identified bacteria causing anthrax, cholera, and TB; contributed to Germ theory

What did Ignaz Semmelweis demonstrate about childbirth mortality?

Infections and mortality in childbirth were greatly reduced if medical personnel use hand disinfection

Who introduced asepsis to prevent wound infections in surgery?

Joseph Lister.

Who created the first smallpox vaccine using cowpox?

Edward Jenner.

why were women immune to smallpox?

because of exposure of cowpox from milking cows

Who introduced variolation (inoculation) to Boston in the early 1700s and predates Jenner cowpox vaccine by decades?

Onesimus, a West African enslaved person.

What categories of microorganisms can cause infectious diseases?

Bacteria, fungi, protozoa, parasitic worms, and viruses.

Who developed the first taxonomic system for organizing organisms?

Carl Linnaeus.

How many levels are in the standard taxonomic hierarchy?

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species (eight levels).

Dear king phylip came over for good soup

How should a scientific name be written?

Genus capitalized, species lowercase; italicized or underlined.

What are the four methods used to identify microorganisms?

DNA sequencing; autotrophic or heterotrophic classification; presence of nucleus and organelles; biochemical testing/staining.

What is the Cell Theory?

All living things are made of cells; the cell is the basic unit of life; all cells come from pre-existing cells.

What are the three components all cells have

Plasma membrane, Cytoplasm, DNA (genetic material), ribosomes (protein synthesis)

What is the basic unit of life?

The cell.

What are the two main categories of cells?

Prokaryotes and Eukaryotes.

Do prokaryotes have a true nucleus?

No; they have a nucleoid region instead of a membrane-bound nucleus.

Do prokaryotes have membrane-bound organelles?

No.

Do eukaryotes have membrane-bound organelles?

Yes.

What is the size comparison between prokaryotic and eukaryotic cells?

Prokaryotes are typically 1–10 μm; Eukaryotes are typically 10–100 μm.

What type of ribosomes do prokaryotes have?

70S ribosomes.

What type of ribosomes do eukaryotes have?

80S ribosomes.

What is the general chromosome structure in procaryotes vs. eukaryotes?

prokaryotes have circular chromosomes; eukaryotes have linear chromosomes.

Do bacteria commonly have plasmids?

Yes; small circular DNA molecules.

What is a nucleoid?

A region in prokaryotes where DNA is located; not a membrane-bound nucleus.

What are two special bacterial wall components that differ between Gram-positive and Gram-negative bacteria?

Teichoic acids are typical in Gram-positive walls; Gram-negative have an outer membrane with LPS.

define fimbriae

small hairlike projections that surround some gram-negative bacteria. allow the bacteria to stick to other bacteria and to surfaces

What is a capsule in bacteria?

A polysaccharide layer strongly attached to the cell wall that helps prevent white blood cells from destroying (prevent phagocytosis) the bacteria. and aids virulence. capsule is what makes streptococcus pneumonia cause pneumonia

pili define

long bacteiral structure used to exchange DNA (conjugation) between bacterial cells

define flagella

tail like structure used by bacteria and other organisms for movement

What is a slime layer (S layer)?

A loose extracellular material that easily comes from bacterial surface. made by some bacteria when exposed to harsh conditions.

What is a plasmid?

Small circular DNA in bacteria that has antiobiotic resistance genes

What is peptidoglycan?

A bacterial cell wall component made of sugars and small peptides.

What are mycolic acids and which bacteria have them?

Fatty components in the cell walls of Mycobacteria that makes it difficult for immune cells to kill bacteria (acid-fast).

What is LPS and where is it found?

Lipopolysaccharide; outer membrane lipids of Gram-negative bacteria. toxin that can trigger a strong immune response

What is an endospore and which bacteria form them?

A dormant cell, surrounded by thiick protective layer that protects agains UV, dehydration, extreme temp. Bacillus and Clostridium.

What is the structure of the plasma membrane?

phospholipid bilayer with embedded proteins and small carbohydrates

what is the function of the plasma membrane

its a semipermeable barrier, provides protection: basically controls what goes in and out of the cell

What design did Pasteur use to disprove spontaneous generation?

Long-necked swan-flask that allowed air but trapped bacteria. and thus prevented broth from being contaminated. in this way he proved that life only comes living things and not by spontaneous generation

Who first described structure of cells and named cells from describing how cork looks under microscope?

Robert Hooke.

What are the Gram stain results for Gram-positive bacteria?

Purple (violet) due to thick peptidoglycan.

What are the Gram stain results for Gram-negative bacteria?

Pink/red due to thin peptidoglycan and outer membrane.

What is the role of teichoic acids in Gram-positive bacteria?

Contribute to cell wall structure and negative charge.

What is the role of the outer membrane in Gram-negative bacteria?

Barrier that protects against certain antibiotics and contains LPS.

What is a capsule’s role in virulence?

Prevents phagocytosis and helps bacteria evade the immune system.

What is an endospore’s role?

Protection during harsh conditions; enables survival.

Which two genera are known for endospore formation?

Bacillus and Clostridium.

What is the role of LPS in Gram-negative bacteria?

Outer membrane lipids that can trigger a strong immune response (endotoxin).

What is the term for bacterial DNA transfer via a pilus?

Conjugation.

What is transduction in bacterial genetics?

DNA transfer mediated by a bacteriophage/virus.

What is transformation in bacteria?

Uptake of foreign DNA from the environment.

What is an operon in bacteria?

A set of genes with a common function arranged closely together in chromosome and that are transcribed and translated together.

What is a codon?

Three nucleotides in mRNA that specify an amino acid.

What is the start codon and what amino acid does it usually specify?

AUG; Methionine.

What are stop codons?

UAA, UAG, UGA.

What is transcription?

Copying DNA into RNA.

Where does translation occur in a cell?

In the cytoplasm (ribosome-assisted decoding of mRNA).

What is the DNA–RNA–protein flow called?

Central dogma.

What enzymes unzip DNA strands during replication?

Helicase.

What prevents overwinding of the DNA as it opens

Topoisomerase.

What enzyme seals gaps between Okazaki fragments?

Ligase.

What is the proofreadin activity of DNA Polymerace

ability to correct some mutations during DNA replication, ensuring high fidelity in the synthesis process.

What are mutations?

Changes in DNA sequence that can inactivate proteins or confer antibiotic resistance.

What is conjugation?

DNA transfer via a direct cell-to-cell contact through a pilus.

What is the difference between plasmids and chromosomes?

Plasmids are small, extra-chromosomal DNA; chromosomes contain the essential genes.

What is a chromosome’s shape in bacteria?

Circular.

What is a chromosome’s shape in most eukaryotes?

Linear.

Where is DNA located in bacteria?

On the chromosome and plasmids within the nucleoid region.

Where is DNA located in eukaryotes?

In the nucleus (and in mitochondria and chloroplasts in some organisms).

What is the term for a bacterial colony’s arrangement of cocci in clusters?

Staphylococcus.

What is the term for cocci in chains?

Streptococcus.

What is a bacillus?

A rod-shaped bacterium.

What is a coccus?

A spherical bacterium.

What kind of growth does a chemostat maintain?

Exponential growth by continuous nutrient supply and removing waste.

What are the four phases of the microbial growth curve?

Lag, Exponential (Log), Stationary, Death.

What are the three classic modes of bacterial growth in a tube regarding oxygen?

Obligate aerobes (top), Obligate anaerobes (bottom), Facultative anaerobes (throughout, more on top).

What is a microaerophile?

Organism that grows best in a thin band below the surface with low oxygen.

What is an aerotolerant organism?

Tolerates oxygen but does not use it for growth.

What categories describe temperature-based microbial groups?

Psychrophiles, Mesophiles, Thermophiles, Hyperthermophiles.

What temperatures do psychrophiles prefer?

Cold temperatures (typical range for cold-loving microbes).

What temperatures do mesophiles prefer?

Moderate temperatures (roughly 15–45°C, many human pathogens are mesophiles).

What temperatures do thermophiles prefer?

High temperatures (roughly 45–80°C).

What temperatures do hyperthermophiles prefer?

Very high temperatures (up to around 105°C or higher).

What is autotrophs?

Carbon obtained from CO2 (often via photosynthesis).

What is heterotrophy?

Carbon obtained from other organisms.

What is CHNOPS an acronym for?

Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur.

What is a fastidious organism?

An organism with special nutrient requirements for growth. blood. picky

What does ‘obligate’ mean in microbial growth terms?

A strict, non-negotiable requirement for growth.

What does ‘facultative’ mean in microbial growth terms?

An organism that can adapt to a range of environmental conditions.

What is a culture medium?

A nutritional broth that supports growth.

Which nutrients are commonly required by microbes?

CHNOPS(Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur) .

How does high temperature affect microbial proteins?

Denatures proteins and disrupts function. inactivates them. as a result proteins lose their funtion, the cell an no longer do all its metabolic reactioons and will die if temp is too high

How does low temperature affect metabolism?

Slows metabolism and biological reactions; usually reversible.

What is the basic structure of the bacterial plasma membrane?

Phospholipid bilayer with embedded proteins and small carbohydrates.

What does the germ theory relate to?

That microorganisms cause diseases; Koch helped formalize evidence for this with postulates.

THE ENDOSYMBIOTIC THEORY

states that mitochondrian and chloroplasts evolved in eukaryotic cells through an ancient symbiotic relationship between cells, bacteria, and cyanobacteria

What evidence supports the endosymbiotic theory

Mitochondria and chloroplasts divide like bacteria , have their own DNA, and have unique membranes; chloroplasts resemble cyanobacteria.

What organelles in eukaryotic cells are thought to have originated from bacteria via endosymbiosis?

Mitochondria and chloroplasts.