Chapter 1: Introduction to Microbiology

_____ is the system that classifies and groups organisms into taxa (categories).

Taxonomy

Microbial classification is based on similarities and differences in _____ and _____.

genotype; phenotype

Phenotypic classification tests _____ or _____ characteristics and compares them with established databases.

metabolic; molecular

In epidemiology, bacterial species may be further subdivided to help follow the _____ of bacterial infections.

spread

Subdivision of a species based on:

phenotypic differences = ___

serologic (antigenic) differences = ___
biochemical test-result differences = ___

subspecies; serospecies; biovariety

Genotypic classification can use _____ gene sequencing to demonstrate genetic relatedness.

ribosomal RNA (rRNA)

The three cellular domains listed in the objectives are _____, _____, and _____.

Eubacteria, Eukarya, and Archaea

_____ includes the typical bacterial species encountered in clinical settings.

Eubacteria

_____ includes fungi, protozoa, algae, animals, and plants.

Eukarya

_____ includes thermophiles, halophiles, and anaerobic methanogens and is not associated with human disease.

Archaea

Prokaryotes include the domains _____ and _____.

Eubacteria; Archaea

In the taxonomy analogy,
family = _____ name
genus = _____ name
species = _____ name

clan; last; first

A _____ consists of organisms of the same species that have varying characteristics.

Ex. Two S. aureus isolates with different penicillin susceptibilities can represent different strains of the ___ species.

strain; same

In bacterial nomenclature, the first letter of the _____ is capitalized and the species name is _____.

It must also be ___ OR printed and ___. Abbreviations must be formatted as: G. species

genus; lowercase

italicized; underlined

_____ are unicellular organisms that lack a membrane-bound nucleus and membrane-bound organelles.

Prokaryotes

_____ have a membrane-bound nucleus and membrane-bound organelles.

Eukaryotes

The prokaryotic nuclear body is called the _____ and is not membrane-bound. Prokaryotic cells have _____ membrane-bound organelles.

nucleoid; no

Ribosomes are the site of _____ synthesis.

protein

In prokaryotes, ribosomes may be free in the _____ or attached to the cytoplasmic _____.

cytoplasm; membrane

Prokaryotic cytoplasmic granules are _____ deposits that may consist of polysaccharides.

storage

Cytoplasmic granules can be visualized with _____ blue stain.

methylene

Bacterial spores appear as highly _____ bodies and as _____ areas on a Gram stain because of their thick protein coat.

refractile; unstained

_____ ER is covered in ribosomes and is a site of protein synthesis.

Rough

_____ ER synthesizes phospholipids.

Smooth

The _____ apparatus modifies and packages proteins and lipids sent to it by the ER.

Golgi

Mitochondria contain DNA and an electron transport system that produces energy in the form of _____.

ATP

The prokaryotic plasma membrane contains _____ sterols - in contrast to eukaryotes.

no

The prokaryotic plasma membrane acts as an _____ barrier and is the location of the electron transport chain.

osmotic

In prokaryotes, the ___ ___ ___ is where energy is generated in the plasma membrane.

electron transport chain (ETC)

The eukaryotic plasma membrane contains _____, which stabilizes the membrane and helps keep it fluid.

cholesterol

The bacterial cell wall is _____ and maintains cell structure.

rigid

Bacterial cell walls may be classified as Gram-positive, Gram-negative, or ___.

acid-fast

The genera _____ and _____ contain a waxy layer that causes poor Gram staining and makes an acid-fast stain more useful.

Mycobacterium; Nocardia

When present, a eukaryotic cell wall provides _____ and strength.

rigidity

A fungal cell wall may contain _____, which differs from the composition of bacterial cell walls.

chitin

Most eukaryotes ___ ___ have a cell wall; a cell wall is a distinct characteristic of fungi.

do not

A bacterial _____ helps a pathogen evade phagocytosis.

capsule

Prokaryotic cell appendages include _____, _____, and _____.

flagella; pili; fimbriae

Eukaryotic motility structures are _____ and _____.

cilia; flagella

Gram-positive bacteria have a _____ peptidoglycan (murein) layer and stain _____.

thick; purple

Antimicrobial agents such as penicillin can act against Gram-positive organisms by preventing synthesis of _____.

peptidoglycan

Gram-positive cell walls contain _____ acid and _____ acid.

teichoic; lipoteichoic

Gram-negative bacteria have _____ cell-wall layers with an inner _____ peptidoglycan layer.

two; thin

Gram-negative bacteria stain _____ on a Gram stain.

pink

The outer membrane of Gram-negative bacteria contains proteins, phospholipids, and _____.

lipopolysaccharides (LPS)

LPS is very _____; if it is present in blood, the immune system will be triggered.

immunogenic

The _____ stain is the most common stain and differentiates Gram-positive from Gram-negative bacteria.

gram

The primary stain in the Gram-stain procedure is _____ violet.

crystal

The Gram-stain mordant/fixative is _____.

iodine

The Gram-stain decolorizer is _____.

acid-alcohol

The Gram-stain counterstain is _____.

safranin

The Gram-stain timing in the objectives is crystal violet _____, iodine _____, acid-alcohol a quick rinse, and safranin _____. (Rinse with water between each step)

1 min; 1 min; 30 secs

Acid-fast stains are used for bacteria whose cell walls contain high amounts of _____ and _____.

lipid; wax

The primary stain used in an acid-fast stain is _____.

carbolfuchsin

In the _____ method, heat is used to allow dye penetration into acid-fast cell walls.

Ziehl-Neelsen

In the _____ method, a detergent is used to allow dye penetration into acid-fast cell walls.

Kinyoun

The acid-fast decolorizer listed in the objectives is _____ and the counterstain is ___ ___.

alcohol; methylene blue

Acid-fast bacteria retain the primary stain and appear _____.

pink

_____ orange is a fluorochrome dye that stains both Gram-positive and Gram-negative bacteria, living or dead.

Acridine

_____ white is a fluorochrome that binds to chitin in the fungal cell wall.

Calcofluor

_____ blue is used to visualize metachromatic granules in C. diphtheriae.

Methylene

_____ cotton blue is used to visualize the cell walls of medically important fungi.

Lactophenol

___ ink is used to visualize capsules around yeast.

India

The three major nutritional requirements for bacterial growth are a _____ source, a _____ source, and an _____ source.

carbon; nitrogen; energy

A carbon source is needed for bacterial ___ ___

cellular constituents

A nitrogen source is needed to make _____ and _____ acids.

proteins; nucleic

The bacterial energy source is _____ and is used for cellular functions.

ATP

_____ use carbon dioxide as their carbon source and obtain energy through photosynthesis or oxidation of inorganic compounds.

Autotrophs

_____ require an organic carbon source such as glucose and obtain energy by oxidizing or fermenting organic substances. All ___ that inhabit the human body are these!

Heterotrophs; bacteria

The three environmental factors that influence bacterial growth rate are _____, _____, and the gaseous composition of the atmosphere.

pH; temperature

Most pathogenic bacteria grow best at a _____ pH.

Bacterial media are usually adjusted to a final pH of approximately _____ to _____.

neutral

7; 7.5

_____ grow best in cold temperatures of about 10–20°C.

_____ grow best at moderate temperatures of about 20–40°C.

_____ grow best in hot temperatures of about 50–60°C.

Psychrophiles; Mesophiles; Thermophiles

_____ (nutritive) media contain nutrients that support the growth of most nonfastidious organisms.

Nonselective

_____ media contain added growth factors such as blood, vitamins, or yeast extract and allow fastidious organisms to grow.

Enriched

_____ media inhibit the growth of some bacteria but allow others to grow.

Selective

_____ media allow visualization of metabolic differences between groups or species of bacteria.

Differential

_____ media are used when there is a delay between specimen collection and culturing.

Transport media are designed to preserve microorganism _____ without allowing _____.

Transport

viability; multiplication

A fastidious organism can be thought of as a _____ organism with special growth requirement.

picky

Obligate ___ requires oxygen for growth; While ___ cannot grow in the presence of oxygen.

Aerobes; anaerobes

_____ anaerobes can grow with or without oxygen. But they grow ___ in presence of oxygen than without it.

Facultative; faster

_____ bacteria grow best when enriched with extra carbon dioxide, about 5%–10%.

Capnophilic

_____ organisms require a reduced level of oxygen for growth.

Microaerophilic

Optimizing atmospheric growth requirements helps ensure recovery and _____ of pathogenic organisms from clinical samples.

isolation

Bacteria replicate by _____ fission, in which one cell divides into two.

binary

Generation or doubling time is the time required for one bacterial cell to _____.

Bacterial generation time may range from about _____ minutes to _____ hours or more.

divide
20; 24