Microbiology Exam 1- DC quizlet

Differential staining

Staining procedure used to distinguish different types of bacteria

Gram stain

The most common differential stain

Pathogenic

Bacteria with a capsule are ______

Non-pathogenic

Bacteria without a capsule are _________

Capsule

A sticky layer that surrounds the cell walls of some bacteria, protecting the cell surface and sometimes helping to glue the cell to surfaces

Bacterial spore

Bacteria capable of producing a protective coating that allows them to withstand very harsh environments, and shed the coating when conditions become more favorable

Gram positive cell walls contains teichoic acid, and gram negative cell walls do not contain teichoic acid

What is the difference between the cell walls of gram negative and gram positive cells?

Purple

What color do gram positive bacteria stain?

Pink

What color do gram negative bacteria stain?

The phagocytes have a harder time attacking bacteria with capsules because they are slimy

Explain why bacteria with capsules are pathogenic

Streptococcus pneumonia

What is the number one cause of meningitis in the US?

Terminal and central spores

What are the two possible locations of spores?

Resistance

Bacterial spores mean ________

Fungal spores are part of the sexual reproduction of fungi. Bacterial spores are for resistance and survival in harsh environments

Explain the difference between bacterial and fungal spores

Prokaryotic cells

Cells with no true nucleus and no membrane bound organelles

Binary fission

A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size

Nucleoid

A dense region of DNA in a prokaryotic cell

Sex pilus

A thin connection between two bacteria through which genetic material passes during conjugation

Attachment and support

What is a pilus used for in bacteria?

Movement

What are flagellum for in bacterial cell walls?

Flagella

The most common mechanism of motility for bacteria

Cell wall

A strong, rigid structure surrounding bacterial and other prokaryotic cells. Prevents cell lysis

Peptidoglycan

What are bacterial cell walls made of?

Peptidoglycan

Polymer that makes up bacterial cell walls. Alternating series of subunits form glycan chains : N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG)

NAM and NAG

The cell walls of bacteria are a polymer of short peptides and repeating chains of_______ and _____

Thick

The peptidoglycan of the gram positive cell wall is _______

Thin

The peptidoglycan of the gram negative cell wall is _______

Lipopolysaccharide (LPS)

Gram negative cells have an outer membrane made from _________

Endotoxin (LPS)

A toxic component of the outer membrane of certain gram-negative bacteria that is released only when the bacteria die

Blocks passage of many molecules including certain antibiotics

What is the significance of Gram negative outer membranes?

Peritrichous flagella

Flagella that cover the surface of a cell

Polar flagellum

Single flagellum at one end of the cell

Monotrichous

Single polar flagellum

Amphitrichous

Polar flagella on opposite sides

Lophotrichous

Multiple flagella at one end

Fimbriae

Types of pili that allow surface attachment

Plasmids

One way in which antibiotic resistance can spread

Cytoskeleton

Internal protein framework

Metachromatic granules

Phosphate reserves within bacteria. Used for ATP synthesis. Lots of multicolored granules

Corynebacterium

What is the only bacterium with metachromatic granules?

Corynebacterium

Metachromatic granules = ________

Lag phase

Exponential (log) phase

Stationary phase

Death phase

What are the bacterial stages of growth?

Lag phase

A short period of time prior to exponential growth of a bacterial population during which no, or very limited, cell division occurs.

Log phase

The period of exponential growth of bacterial population

Growth rate exceeds the death rate

In the log phase, the _____ rate exceeds the _____ rate

Stationary phase

Period of equilibrium - the growth rate equals the death rate

Death phase

Period in which the death rate exceeds the growth rate

Synthesizing enzymes needed for growth. Delay depends on conditions

If no growth occurs during the lag phase, what is happening?

During the exponential phase

At what phase of the growth curve are bacteria most sensitive to antibiotics?

Exponentially

2 --> 4 --> 8 --> 16 --> 32 --> 64, etc.

How do bacteria grow?

Obligate aerobe

Organism that requires a constant supply of oxygen in order to live

Facultative anaerobes

Organism that grows best if O2 is present, but can also grow without it

Obligate anaerobe

Organism that cannot grow in the presence of O2

Microaerophile

Organism that requires small amounts of O2; too much O2 is inhibitory

Aerotolerant anaerobe

Organisms that do not use oxygen but tolerate it's presence

Neutrophile

Bacteria that grow in the pH range 5-8

Acidophile

Bacteria that grows optimally at a pH below 5.5

Alkalophile

Bacteria that grows at a pH above 8.5

Mesophiles because they grow at human body temperature (37)

Which type of bacterial microbes are human pathogens and why

Virus

A tiny, nonliving particle that invades and then reproduces inside a living cell

Capsid

Outer protein coat of a virus

Virion

A fully formed virus that is able to establish an infection in a host cell

Capsomeres

Protein subunits that make up capsids

Nucleocapsid

Capsid and nucleic acid together

Icosahedral

A virus made up of equilateral triangles fused together in a spherical shape. This is the most optimal way of forming a closed shell using identical protein subunits. The genetic material is fully enclosed inside of the capsid.

Poliovirus

Rhinovirus

Adenovirus

Give 3 examples of viruses with icosahedral structures

Naked virus

A virus with no envelope

Enveloped virus

A virus enclosed within a phospholipid membrane derived from its host cell

Influenza virus

Hepatitis C

HIV

What are the 3 most well known examples of enveloped viruses?

Spikes

Projections that extend from the viral envelope that may aid in attachment to the host cell. Contain enzymes

Hellical virus

This virus structure has a capsid with a central cavity or hollow. Tube that is made by proteins arranged in a circular fashion, creating a disc-like shape

No, one or the other

Can a single virus have both RNA and DNA?

Bacteriophage

Virus structure with a combination of icosahedral and helical shape and may have a complex out wall or head-tail morphology.

Bacteriophages

Head-tail morphology structure is unique to what kind of viruses?

Bacteriophage

A virus that infects bacteria

They attach and inject their nucleic acid into the cell.

How do bacteriophages infect bacteria?

Complex symmetry

Viruses that have both helical and icosahedral symmetry have _______ symmetry

No

Do bacterial viruses enter the cell?

Yes, they have an enzyme that allows them to get into the cell. Once they get in, they uncoat and release their genetic material

Do animal viruses enter the cell?

In host cell DNA

Where are DNA viruses replicated?

At host cell ribosomes

Where are RNA viruses replicated?

Retroviruses

Use reverse transcriptase to copy their RNA genome into DNA

Oncogenic viruses

Viruses capable of inducing tumors

Epstein-Barr virus (Burkitt lymphoma)

Human Papilloma virus (HPV) - cervical cancer

List 2 oncogenic viruses

Rhinoviruses

Responsible for 30-50% of cases of the common cold

Neuraminidase

One of the enzymes found on the surface of the Influenza virus. It promotes the release of progeny viruses from infected cells

Inhibit the release of influenza A and B from the host cell, stopping replication. Blocks Neuraminidase

How does Tamiflu work?

Hemagglutinin

One of the enzymes found on the surface of the Influenza virus. It is responsible for binding the virus to the cell that is being infected

Antigenic drift

A mechanism for variation in viruses that involves the accumulation of mutations within the genes that code for antibody-binding sites.

Mutations that affect the binding sites of the virus or bacteria. Occurs over time

Due to antigenic drift. You have to revaccinate to account for change in the binding site - need new antibodies

Why is it necessary to revaccinate every year for the flu?

Influenza A

Strikes every year and causes most epidemics. Most pronounced antigenic drift

Antigenic shift

Abrupt, major changes to influenza A virus, causing epidemics. Example is a new HN combination. Causes a new subtype of the disease.

Antigenic shift

Swine flu occurred due to _________

A

Influenza type that can undergo both antigenic drift and antigenic shift

B

Influenza type that can only undergo antigenic drift

Antigenic shift

H3N2 and H5N1 combined their antigens to form H5N2. What is this phenomenon called?

Common cold

Rhinovirus and adenoviruses cause _________

Primary infection

Acute infection that causes the initial illness

Secondary infection

Opportunistic infection after a primary (predisposing) infection. Occurs in the compromised individual

Adenovirus

Which virus causes the more severe cold, rhinovirus or adenovirus?