Microbiology Exam 2

Bacteria are __________ meaning they are in water, on land, extreme environments and on/within eukaryotes.

Ubiquitous

Why are bacteria small?

A high surface area to volume ratio favors diffusion

Round shaped bacteria are called _________.

Cocci

Long pill shaped bacteria is called ________.

Bacillus

A chain of cocci are called a ________.

Strep

A cluster of cocci are called a __________.

Staph

A chain of bacillus is called a ___________.

Strep

A cluster of bacillus is called a _________.

Palisades

A comma shaped bacteria is refered to as _________.

Vibrio

A variable shaped bacteria is refered to as _______.

Pleomorphic

(Monomorphic/Pleomorphic) bacteria have one shape

Monomorphic

True or False: Prokaryotes contain a nucleus.

False

The site of all cellular functions and structures in a prokaryote:

Cytoplasm

Localized region of bacterial genome (typically a singular circular DNA chromosome):

Nucleoid

The protein synthesis factories of bacteria. Translates genetic code into amino acids.

Ribosomes

Dense particles of aggregates in the bacteria. These are the surplus storage sites and sites of viral reproduction.

Inclusion bodies

Filamentous protein structures in bacteria that give structure and support to cell shape and functions:

Cytoskeleton

True or False: Bacteria does not contain any membrane bound organelles

True

The plasma membrane of a bacterial cell contains a flexible _____________ containing membrane proteins.

Phospholipid Bilayer

In a selectively permeable plasma membrane, larger substances require _________ to enter or exit a cell.

Protein transporters

(Passive/Active) transport requires energy

Active

H₂O will move across a membrane from _____ to _____ solute concentration.

low, high (water follows salt)

(Passive/Active) transport is faster

Active

During active transport substances move across biological membrane from an area of ____ to _____ concentration:

low, high

During passive transport substances move from a region of _______ to _______ concentration.

high, low

(Passive/Active) transport is bidirectional

Passive

Do other prokaryotes besides bacteria have peptidoglycan cell walls?

No

Peptidoglycan cell walls are made up of _______ and ________.

Sugar, protein

Differential staining technique that classifies bacteria into categories based on differences in chemical and physical cell wall properties:

Gram-stain

Can Gram-staining be used to identify an exact type of bacteria?

No

True or False: Not all bacteria will fall into a Gram-Positive or Gram-Negative category.

True (Spirochetes, Mycoplasmas, Mycobacteria)

(Gram-negative, Gram-positive) bacteria have a 2nd membrane (outer membrane) rich in lipids. They contain a thin layer of peptidoglycan between the cell membrane and the outer membrane.

Gram-negative

(Gram-negative, Gram-positive) bacteria have a single cell membrane and a thick layer of peptidoglycan.

Gram-positive

Does Gram-negative or Gram-positive bacteria have a second membrane called the outer membrane?

Gram-negative

The outer membrane of Gram-negative bacteria is home to _________ and _________.

LPS, Porins

The cell wall of Gram-positive bacteria includes the presence of ________ which stabilize the cell wall and help to maintain the shape and felxibility as well as aid cell division.

teichoic acids (TAs)

If a bacteria can not be determined as Gram-negative or Gram-positive, it is considered ____________.

Gram-intermediate

Only ~___% of all bacteria is harmful.

5

The fluidity of the Fluid-mosaic lipid bilayer is affected by _________ and __________.

Temperature, Composition

Gram-negative bacteria will stain (red/purple).

Red

Gram-positive bacteria will stain (red/purple).

Purple

The Mycoplasma bacteria species lacks a ___________, classifying it as Gram-intermediate

Cell Wall

(Mycoplasma/Mycobacteria) has a thick, mycolic acid rich cell wall.

Mycobacteria

Why is Mycobacteria considered Gram-intermediate?

It’s cell wall is so thick that the dye can fail to penetrate it.

The ______________ is the sticky, carbohydrate-enriched, mucoid layer of bacteria.

Glycocalyx

The (Slime layer/Capsule) is the primary virulence factor of bacteria.

Capsule

Why is the Glycocalyx (Slime and Capsule layers) important to bacteria’s virulence?

It helps the bacteria adhere and protects it from immune response, anibiotics, disinfection, etc.

True or False: A bacteria with no polysaccharide capsule will not cause invasive disease.

True (No resistance to immune response, antibiotics, etc.)

Bacterial protein subunit appendages that extend outward and interact with the environment:

Filamentous Appendages

(Fimbria, Pili/Flagella) functions in attachement in bacteria.

Fimbria/Pili

(Fimbria, Pili/Flagella) functions in motility in bacteria.

Flagella

Motile response towards or away from an environmental stimulus such as temperature, light, chemicals, etc.:

Taxis

_________ allow for corkscrew-like movements in spirochetes.

Endoflagella

_____________ are dormant, tough, and highly resistant survival structures produced by certain Gram-positive bacteria during times of environmental stress like nutrient starvation. These can be very dangerous expecially in food preparation and healthcare facilities.

Endospores

What are the five steps to infection?

1.) Enter host

2.) Adhere to host tissues

3.) Invade tissues and/or obtain nutrients

4.) Replicate while warding off immune defenses

5.) Transmit to new host

Specificity for adhesin attatchment to a particular host cell surface marker is due to ____________.

Tropism

Preference of a pathogen for a specific host and/or a specific cell or tissue within the host ___________.

Tropism

Cooperatively functioning microbial communities encased in a self-secreted sticky substance that forms a protextive surrounding matrix:

Biofilm

Comprised of biopolymers of microbial origin in which biofilm microorganisms are embedded (a sticky mix of macromolecules that form the structural matrix of a microbial biofilm):

EPS

Cell-to-cell chemical communication system allowing microbes within the biofilm to coordinate activities/alter gene expression to benefit the community:

Quorum sensing

__________ formation is linked to persistant, recurrent, and often treatment-refractory infections

Biofilm

Membrane associated or secreted virulence factors that function to assist microbial invasion. These act locally to damage host cells and/or have immediate effect of facillitating the growth and spread of the pathogen.

Invasins

__________ break down nutrients in the local environment or facilitate spread of bacteria.

Exoenzymes

Exoenzymes end with the suffix _________.

-ase

Soluble proteins produced and actively secreted or released in both Gram+ and Gram- bacteria with adverse host effects (toxic and active in low concentrations)

Exotoxins

Lipid A portion of LPS within Gram- bacterial outer membrane. Released upon cell lysis (inflammitory)

Endotoxins

True or False: Gram+ bacteria can release endotoxins

False (only Gram-)

Toxin deactivated by heat or chemical treatment have been used to produce successful _______ vaccines.

Toxoid

True or False: Infection is required to be affected by a toxin

False (Food poisoning, botox, etc.)

In sufficient quantaties endotoxins can result in _____________.

septic shock

(Endotoxins/Exotoxins) can be deactivated and made into vaccines.

Exotoxins

Pathogen covers itself in host factors to avoid immune detection:

Antigen masking

Pathogen’s antigens resemble host molecules, helping it evade immune detection:

Antigen mimicry

Pathogen switches its antigens. thwarting the mounting immune response.

Antigen variation

Ability of a pathogen to remain dormant, then cause persistant or reccurent disease

Latency

Number of pathogens needed to establish an infection in 50% of exposed hosts:

Infectious Dose 50 (ID50)

More infectious pathogens have a (higher/lower) ID50

lower

Does highly infectous = dangerous?

No

Amount of pathogen/toxin needed to kill 50% of affected hosts that are not treated:

Lethal dose 50 (LD50)

A (higher/lower) LD50 means higher virulence

lower

Bacteria reproduces (sexually/asexually) through _________.

asexually, binary fission

During binary fission there (is/is not) an exchange of genetic information

is not

True or False: Bacteria double through binary fission up to 3 times a day.

False (Rates vary enormously)

In what stage of bacterial growth do the number of living bacterial cells plateu (the rate of cell division and death are roughly equal)?

Stationary

During which phase of bacterial growth are endospores made?

Stationary

During which phase of bacterial growth are endospores released?

Death/decline phase

Most bacteria can survive (freezing/heat) and are killed by (freezing/heat).

freezing, heat

(Acidophiles/Neutrophiles/Alkaliphiles) grow at <pH 1-4

Acidophiles

(Acidophiles/Neutrophiles/Alkaliphiles) grow in the pH range of 5-8

Neutrophiles

(Acidophiles/Neutrophiles/Alkaliphiles) grow at the pH range of 9-11

Alkaliphiles

(Acidophiles/Neutrophiles/Alkaliphiles) make up the majority of microorganisms

Neutrophiles

Most cells undergo ____________ in high-salt

Plasmolysis

True or False: Facultative halophiles (halotolerant) organisms do not require salt for growth, but can survive and divide in it’s presence

True

_____________ have an absolute dependence on O2 for growth

Obligate aerobes

__________ do not use O2 and may die in it’s presence.

Obligate anaerobes

__________ thrive in O2, but neither need it or use it.

Aerotolerant anaerobes

__________ live in low O2 environments and need/use small amounts.

Microaerophiles

Aerobic organisms must be able to detoxify ______________ to prevent damage to DNA, proteins, lipids, etc. and prevent cell death.

ROS (Reactive Oxygen Species)

What are the three main enxymes that break down toxic byproducts from aerobic respiration?

SOD, peroxidases, catalase

Anaerobes have (SOD/Peroxidases/Catalase/All/None)

None