#1 BIOL 2051 EXAM 1

what are Koch's Postulates?

1. the microorganisms must be present in every case of the disease but absent from healthy individuals
2. the suspected microorganisms must be isolated and grown in pure culture
3. the same disease must result when the isolated microorganism is inoculated in a healthy host
4. the same microorganism must be isolated again from the diseased host

why was the discovery of phagocytic cells in the blood important?

foundational discovery for CELL-MEDIATED IMMUNITY

why does the field of microbiology include macroscopic organisms like algae and fungi?

their study requires techniques like isolation, sterilization, and culturing

what is scanning electron microscope (SEM) used for?

observing a specimen's three dimensional topography

what limitation does heat fixing a bacterial smear have?

distorts internal stuctures

what is the primary stain used in gram staining procedures?

crystal violet

what is the purpose of applying a counterstain in a differential staining procedure?

adds a visible color to the decolorized cells

what is the purpose of using mordant in flagella staining?

increases the diameter of the flagella to make them visible

what is the term for bending light as it passes from one medium to another?

refraction

what was the feature of Pasteur's swan neck flasks that prevented contamination of the sterile broth?

long curved neck trapped airborne microbes and dust

what microscope has a resolution powerful enough to observe individual atoms?

scanning tunneling electron microscope

which microscope is suited for observing intracellular structures by enhancing contrast in living cells that have slight differences in refractive index?

phase-contrast microscope

which staining technique is used to visualize bacterial capsules?

negative staining

which type of microscope produces a bright image of an object against a dark background and is ideal for observing living unstained specimens?

dark field microscope

which type of microscope uses a beam of electrons passing through a thin section of specimen to create an image of its internal structures?

transmission electron microscope (TEM)

who demonstrated that dust is a carrier of microbes and also provided evidence for heat resistant bacteria?

john tyndall

who developed antiseptic surgical techniques to prevent wound infection and indirect evidence for germ theory of disease?

joseph lister

who was the first person to observe and describe microorganisms using his own microscope?

antony van leeuwenhoek

what type of light does a fluorescence microscope require the specimen be exposed to excite its fluorophores?

ultraviolet, violet, or blue light

what genus of bacteria is identified using acid fast staining as a differential procedure?

mycobacterium

what vaccination did Edward Jenner pioneer that uses material from cowpox lesions?

smallpox

what is the function of iodine in gram staining?

serves as a mordant, forming an insoluble complex with the primary stain

what vaccines did Pasteur develop?

anthrax, rabies, and chicken cholera

what is microscope resolution?

the ability of the microscope lens to distinguish between two small objects that are close together

what is the atomic force microscope used for?

viewing surfaces that do not conduct electricity well

what is the outcome of the gram stain procedure?

the alcohol decolorizer dissolves the gram negative outer membrane and washes the dye complex out through the thin peptidoglycan later

what is a similarity between prokaryotic nucleoid and the eukaryotic nucleus?

the use of DNA as the repository of genetic info

which component is primarily responsible for the pyrogenic activity associated with gram negative sepsis and constitutes a major part of the outer membrane?

lipopolysaccharide (LPS)

what could happen if a virus mutates and prevents the synthesis of its own polysaccharide capsule?

the bacteria will be highly susceptible to phagocytosis by host immune cells

which surface appendage is essential for bacterial conjugated and has the ability to bind to certain bacteriophages?

six pilus

what do bacterial plasma membranes usually lack?

sterols like cholesterols

what two things make bacterial endospores highly heat resistant?

dehydrated state and high concentration of calcium dipicolinate

what is unique about the capsule of Bacillus anthracis?

it is composed of a y-glutamyl polypeptide

why is the periplasmic space of gram negative bacteria a functionally distinct compartment?

it contains hydrolytic enzymes, binding proteins, and chemoreceptors

what energizes the rotational motor of a bacterial flagellum?

transmembrane flow of protons (proton motive force)

at what stage of sporulation does the asymmetric cell division that segregates the chromosome and creates a forespore occur?

stage 2

what primary structural difference in the peptidoglycan of E. coli and Staphylococcus aureus?

the E coli peptidoglycan is thinner and less extensively cross linked

what will happen if a gram positive bacteria is treated with lysozome while suspended in a hypotonic solution?

the cell will undergo osmotic lysis

where does the respiratory chain, ATP synthesis, and biosynthesis of membrane lipids and cell wall polymers take place in bacterial cells?

plasma membrane

which organism would be susceptible to an antibiotic that inhibits transpeptidase enzymes and is responsible for foriming peptide bridges in peptidoglycan?

Stapholococcus aureus

what makes lipoteichoic acids (LTAs) structurally and functionally different from wall teichoic acids (WTAs)?

they are anchored in the cytoplasmic membrane by a lipid moeity

what organism domain does a prokaryote with a cell wall that contains talosaminuronic acid and lack D-amino acids?

archaea domain

what is the role of porin proteins found in the outer membrane of E. coli?

to form non-specific channels for the diffusion of small hydrophilic molcules

if the adhesion of certain strains of E. coli to host cells can be blocked by monosaccharide mannose which is mediated by lectin like proteins, then structure is this mediated on?

common pili (fimbriae)

what is a medium called when all chemical components are precisely known and quantified?

synthetic medium

what type of media would be used to determine if a microbe has the ability to ferment a specific sugar?

carbohydrate fermentation media

what is a culture that consists of a single microbial species without any contaminants?

pure culture

a reducing medium that limits free oxgen is specifically designed for cultivating what type of microorganisms?

anaerobes

which isolation method involves embedding a diluted sample within liquefied agar that is then solidified in a plate?

pour plate

what is the most common solidifying agent used to create microbiological media?

agar