Microbio Exam 1

pathogen

term used to describe a disease-causing microorganism

Archaea differ from bacteria because archaea

have cell walls composed of substances other than peptidoglycan

Who created the 3 domains that classify based on the cellular organization of organisms?

Carl Woese

What are the 3 domains?

archaea, bacteria, and eurkarya

What do protozoan motility structures include?

cilia, flagella, and pseudopods

What does a prokaryotic cell not have?

a nucleus

fungal infections are studied by

mycologists

What did Robert Koch identify the cause of?

anthrax

Determining the cause of a new emerging disease by scientists studying disease transmission is an example of utilizing what theory?

Koch’s postulates

Who disproved the arguments supporting spontaneous generation?

Loius Pasteur

Who is credited for first observing microorganisms?

Anton van Leeuwenhoek

Who is credited with first observing cells?

Robert Hooke

Prokaryotic cells do

reproduce by binary fission, have plasma membrane, have circular chromosome

Prokaryotic cells don’t

have membrane-enclosed organelles, have DNA within an enclosed membrane

Streptococci

Capsule

structure that protects bacteria from being phagocytized

Gram positive cell walls contain

teichoic acids

Gram negative cell walls

are decolorized by a brief exposure to alcohol

What do both gram positive and negative cells have?

a cell wall structure that protects against osmotic lysis

What cell wall possesses lipid A / endotoxin responsible for symptoms associated with infection?

gram negative

Gram negative cells do

have extra outer layer, are toxic to humans, protect cell in hypotonic environment, gram reaction due to outer membrane

Gram negative cells do not

have a sensitivity to penicillin

In bacterial ribosomes, a small 30S subunit and a large 50S subunit come together to produce the functional 70S ribosome. Why isn't it an 80S ribosome?

S stands for Svedberg units, which indicates the relative rate of sedimentation due to size, weight, and shape of a particle. The numbers aren't strictly additive.

DNA found in most bacterial cells

is circular in structure

Where are phospholipids most likely found in a eukaryotic cell?

the plasma membrane and organelles

Where are phospholipids most likely found in a prokaryotic cell?

the plasma membrane

What is the purpose of endospores?

allow a cell to survive environmental changes by producing a dormant period with no growth

What is not a typical characteristic of most bacterial plasma membrane?

contains cholesterol

What is not found in / observed in both mitochondria and prokaryotes?

cell wall

What is found in / observed in both mitochondria and prokaryotes?

binary fission, ATP-generating mechanism, 70S ribosomes, circular chromosomes

You have isolated a motile, gram-positive cell with no visible nucleus. You can safely assume that the cell

has a cell wall

What is true concerning the gram-positive cell wall

it contains teichoic acids, it’s sensitive to lysozyme, penicillin, and maintains the shape of the cell

Do gram-positive cell walls protect cell in a hypertonic environment?

no, the cell wall can’t prevent water from moving outside of it

What is the best reason why oxygen can cross the plasma membrane by simple diffusion, but glucose must be transported across the barrier by facilitated diffusion?

Oxygen is a much smaller molecule, making it easier to pass through the molecules of the plasma membrane

What organelle most closely resembles a prokaryotic cell?

mitochondrion

Into which group would you place a photosynthetic organism that lacks a nucleus and has a thin peptidoglycan wall surrounded by an outer membrane?

proteobacteria (gram-negative bacteria)

Into which group would you place a unicellular organism that has 70S ribosomes and a peptidoglycan cell wall?

bacteria

Into which group would you place a photosynthetic cell that lacks a nucleus?

bacteria

What is the best evidence for a three-domain system?

nucleotide sequences in ribosomal RNA vary between all three domains

What characterizes the domain bacteria?

prokaryotic cells; ester linkages in phospholipids

In the scientific name Enterobacter aerogenes, Enterobacter is the

genus

What are characteristics of algae?

may be unicellular or multicellular, produce harmful toxins, mostly live in aquatic habitats, most are photoautotrophs

Hypotheses can be followed by further

observations without experimentation

Virology is different than the other areas of microbiology because

viruses are not cells

HIV is an exception to Koch’s Postulates because

it does not cause AIDS in an experimental host

Which is not a control in Pasteur’s Disproof of Spontaneous Generation experiment?

Pour meat broth into flask, bend neck, boil and watch

Epulopiscium is an exception to the size rule. It is a very large

bacterium

An average eukaryotic cell is how much bigger than an average virus with respect to volume?

1,000,000 times

Which is not a domain?

Animalia

In Pasteur’s Disproof of Spontaneous Generation experiment, he was lucky because

his sample didn’t contain endospores

All bacteria have

cell membrane, cytoplasm, nucleoid and ribosomes

Membrane-bound organelles are usually found in

eukarya

The Endosymbiont Theory has to do with the origin of

mitochondria

The nucleoid is

usually single, circular, haploid and double-stranded DNA

A plasmid is always made of

double-stranded DNA

After the Gram stain procedure, Gram positive and Gram negative bacteria should be obvious after the

application of safranin

Peptidoglycan

is found in greater amounts in Gram positive bacteria than Gram negative bacteria

What is not a characteristic of the cell membrane?

maintains cell shape, such as rod or spirillum (fluid flexible layer)

Which type of solution causes a cell’s cytoplasm to shrink?

hypertonic

The structure that is required for disease to occur, specifically pneumonia caused by Streptococcus pneumoniae or dental cavities caused by Streptococcus mutans, is a

capsule

The shape and arrangement of bacteria associated with the normal bacteria growing on human skin and MRSA is

staphylococci

The bacteria that cause syphilis and Lyme Disease are

spirochetes

The fact that prokaryotes have no membrane-bound organelles, in general, means that prokaryotes

have more proteins in their cell membranes than eukaryotes do

the barrier function of the cell membrane is due to its

lipids

the strength of the gram negative bacterial cell wall is due to its

peptidoglycan

The toxic part of a gram negative bacterial envelope is the

lipopolysaccharide

The second deadliest toxin known is

diphtheria toxin

Which resistance factor is the most important to the endospore-forming bacterium in the natural environment?

desiccation

What are obligate intracellular parasites?

rickettsiae and chlamydiae

What are the differences between molds and yeasts?

molds are aerobic while yeasts are facultative anaerobes

How long can endospores survive?

millions of years because they are totally dormant

What organism doesn’t have to be present to cause its specific disease?

clostridium botulinum

Amoebic dysentery is caused by

a protozoan

Cyanobacteria are not algae because

they don’t have chloroplasts

Approximately 500 million people suffer from trachoma. This disease is caused by

chlamydiae

Correct order of the events in the scientific method

hypothesis, experimentation, observation, theory, law

The curved neck on one of Pasteur’s flasks was important because

it allowed free exchange of air while trapping airborne dust and microorganisms in the bend, keeping the sterilized broth free of contamination

Anton van Leeuwenhoek is famous because

he reported his observations to the Royal Society of London

The smallest size that the human eye can resolve is approximately

100 um

The Endosymbiont Theory says that the mitochondria and chloroplasts are derived from prokaryotic organisms. What evidence leads to this theory?

these organelles contain circular DNA and 70S ribosomes

What disease organism cannot be grown in pure culture on artificial media?

treponema pallidum

Ockham’s Razor states that

the theory with the least assumptions is probably the correct one

The most abundant life forms on earth, the archaea

are mostly anaerobic

What is true about cell membranes?

the proteins require the lipids to be in a somewhat fluid state to function properly

You are observing a cell through a microscope and note that it has no nucleus. You can conclude that it

might be a member of the archaea

Movement in most motile prokaryotes is due to

flagella

Gram positive and gram negative bacteria differ in

chemical composition of their cell walls

Bacteria have a greater proportion of

proteins in their cell membranes than eukaryotes

What is required in streptococcus pneumoniae to cause disease?

a bacterial capsule

the cell membranes of bacteria basically carry out the functions of

eukaryotic membrane-bound organelles

The sporulation process in Bacillus and Clostridium is induced by

starvation for certain nutrients

What is the deadliest toxin known?

botulinum toxin

The difference in ribosomes in eukaryotes and prokaryotes is important because

70S ribosomes are targets for many antibiotics

an atypical bacterium that requires a vector (tick) to be transmitted to humans

Rickettsia

What does chlamydia cause?

an STD and trachoma

What do streptomyces produce?

antibiotics

If you removed the cell wall from a bacterium, what type of solution could you put the wall-less bacterial cell in to give it the best chance for survival?

isotonic

What domain of life contain a nucleus?

Eucarya

In 1869, Thomas Welch was given credit for being the first to

develop a method to produce unfermented grape juice

What is the smallest known living organism?

mycoplasma