Microbiology Exam 1

What is microbiology

The study of all organisms too small to be viewed with naked eyes

Name 6 microbes

* Archaea
* Viruses
* fungi
* prions
* protozoa
* algae

Where ever life exists, ____ are present

microbes

Most microbes are %%helpful/harmful%%, only a few are %%helpful/harmful%%

Most microbes are helpful, only a few are harmful

Harmful microbes are called what?

Pathogenic

One meter is equal to how many micrometers?

10^-6 meters

One meter is equal to how many nanometers

10^-9 meters (one billionth of a meter)

Give the general size of bacteria in micrometers

1-5 micrometers

Give the general size of eukaryotic cells

greater than 10 nanometers

Give three examples of akaryotes

* viruses


* prions


* viroids

Define prokaryotes and eukaryotes in terms of nucleus

prokaryotes: Before nucleus

eukaryotes: true nucleus

Tailed viruses that infects bacteria are called what

phages

What kind of microscope must you use to look at viruses?

Electron microscopes

Name the 6 common bacterial shapes

* Coccus
* Bacillus (Rods)
* Vibrio
* Cocobacillus
* sprilium
* spirochete

What is a word for fungal growth

Mycelium

Who’s the father of microbiology, what did he do?

Leeuwenhoek. Made advances in microscopy and was the first to observe microbes

Who made the small pox vaccine and what was it made of?

Dr Jenner from cowpox

What did Pasteur do? (4)

* Developed pasteurization
* Made rabies vaccine
* Made anthrax vaccine
* Disproved spontaneous generation

What did Dr Simmelweis do?

* Developed antiseptics
* Made Handwashing commonplace in medical settings

What is robert Koch known for?

Germ theory of disease

What are the four postulates of germ theory of disease?

1\.) The infectious agent must be present in all diseased animals

2\.) The infectious agent must be grown in a pure culture and characterized

3\.) Re-inoculation of the agent triggers the same symptoms

4\.) The organism must be re-isolated and re-characterized

What are the three main roles of modern microbiology? describe them a little

* Medicine/Public Health
* Immunology, vaccination, epidemiology
* Science
* Molecular biology, genomics, enzymology, diversity & evolution
* Industry/technology
* Fermentation, agriculture, food, drugs

All microbes follow the same binomial naming system except what?

Viruses

Give the rules to naming species.

Genus and species. Genus is capitalized, species is not. Genus can be abbreviated, species cannot. Must underline each separately if handwritten.

Defining species in bacteria is different as interbreeding cannot be used because…?

Prokaryotes are asexual

How do you define bacterial species?

Collection of strains that share many stable properties and differ significantly from other groups of strains. They share the same sequences in their core housekeeping (essential) genes

Strains are descended from what? Are they all the same or different?

Descended from a single, pure microbial culture. They vary from each other in many ways

What are the three types of ways strains can differ? Describe them

* Biovars: Differ biochemically and physiologically (enzymes)
* Morphovars: Differ morphologically (lines on growth media)
* Serovars: Differ in antigenic properties (surface proteins)

What is the definition of a genus?

A well defined group of one or more species

What are the 5 characteristics used in classification? Describe the,

* Morphological: Shape/size/structure/etc.
* Ecological: O2 requirement/Temperature range, etc.
* Physiological/biochemical: fermentation products/enzymes/motility/etc.
* chemistry: Cell wall structure/chemical composition/etc.
* serology: Surface proteins
* genetics/molecular biology: Mode of gene exchange, DNA/RNA sequences

What are the three domains of life?

Bacteria, Archaea, and Eukarya

Eukarya are eukaryotic, bacteria are prokaryotic, what are archaea?

Prokaryotic

Name three structures present on the outside of a prokaryotic cell

* fimbriae
* pilus
* flagellum

Name three structures present In the envelope of a prokaryotic cell

* Capsule
* Cell Wall
* Plasma Membrane

Name five structures present on the inside of a prokaryotic cell

* 1 chromosome (DNA)
* Plasmid (DNA)
* Ribosomes
* inclusion bodies
* spores

Name the five common arrangements of prokaryotic cells and describe them

* Coccus: Single coccus
* Diplococcus: Pair of 2 cocci
* Tetrad: 4 (square) cocci
* Streptococcus: Chain cocci
* Staphylococcus: Cluster cocci
* Bacillus: Single rod
* Strepto-bacillus: Chain of rods

What form is prokaryotes genetic information in? (Single stranded, double stranded, DNA, RNA, etc?) Where in the cell is it found and whats it’s shape?

Double stranded DNA in a circular chromosome. It is found free floating the cytoplasm in the nucleoid region as it has no nucleus.

Additional bacterial DNA is found in what?

Plasmids

Give an example of a gene that could be found in a plasmid

Antibiotic resistance genes, toxin genes, etc.

What are inclusion bodies in prokaryotes? What can they prevent?

Storage compartments for nutrients in unstable environments. Prevent starvation

What stage is special for bacterial endospores? What can it be used against?

It is a small, dormant, resistance stages. Protect against Heat, uv, acids, etc.

Why do spores form?

They form during stress, like starvation.

How long can spores keep DNA alive?

Thousands of years

Describe the 6 steps of sporulation

1\.) DNA replicates

2\.) Membranes form around DNA

3\.) Forespore forms addition membranes

4\.) Protective cortex forms around spore

5\.) Protein coat form around coretex

6\.) Spore is released, cell breaks down

The preferred stage of sporulation is cellular growth, or _____. This is when spores form during good growth conditions.

Germination

The bacterial plasma cell membrane is what kind of model?

Fluid mosaid model

What are the two main roles of the bacterial plasma cell membrane

1\.) Respiration (Site of electron transport chain)

2\.) Uptake of nutrients (Simple/passive diffusion gives gasses/h2O, facilliated diffusion,active trasport)

Facilitated diffusion and active transport are ways a bacteria gets nutrients. One requires ATP and another doesn’t, which is which?

Active transport requires ATP as it goes across a concentration gradient, Facilitated diffusion does not.

The bacterial cell wall is made of what?

Peptidoglycan layers

What do gram positive bacteria have in their cell wall that gram negative do not? Is it the thick or thin wall? Is is the rigid wall?

Gram positive bacteria have Teichoic acid. It is thick and rigid.

What do gram negative bacteria have in their cell wall that gram positive do not? Is it the thick or thin wall? Is is the rigid wall?

Gram negative bacteria have LPS (lipopolysaccharide molecules) endotoxins embedded in the outer membrane. It is a thin wall. It is NOT rigid.

What kind of bacteria produce waxy, mycolic acid on the exterior of the peptidoglycan layer.

Some gram positive mycobacteria

Which kind of bacteria (Gram positive or gram negative) give a blue gram stain? Which give red?

* Blue gram stain: Gram positive
* Red gram stain: Gram negative

Which kind of bacteria (Gram positive or gram negative) have an outermembrane?

Gram negative have an outer membrane

Which kind of bacteria (Gram positive or gram negative) are more resistant to penicillin and lysosomes?

Gram negative bacteria

Which kind of bacteria (Gram positive or gram negative) are more resistant to osmotic pressure?

Gram positive bacteria

What are the two main roles of capsules?

1\.) Protection against phagocytes/phagocytosis

2\.) Adhesion to tissues

Capsules are very common in what kind of pathogen?

Bacteria

%%Fimbrae/Pilli%% are typically numerous and short.

%%Fimbrae/Pilli%% are typically longer and less in number.

* Fimbrae are typically numerous and short.
* Pilli are typically longer and less in number.

What two things can pili do?

1\.) Attach to other bacteria

2\.) Can allow for conjugation

Fimbrae can do what two things? What can it not do that pili can?

1\.) Attachment to other bacteria

2\.) Adhesion to tissue

can NOT do conjugation

What is flagellum made of?

Basal body, hook, and filament

What does flagellum allow?

motility

Both gram positive and gram negative bacteria have flagellum, but they differ. Explain how?

Gram positive have 2 rings, gram negative have 4 rings

What protein does flagellum use?

Flagellin

How does flagellum move?

It rotates clockwise/counterclockwise by rings of the basal body

Define chemotaxis

Overall directional movement toward/or away higher concentration of attachment

Explain the run and tumble of flagellum? What’s their speed?

They '“run” in a straight line, in a counterclockwise movement. They then ‘tumble’ clockwise and sense the environment. Can reach 10-50 micrometers a second

Eukaryotic cells can be described as highly _______.

organized

Eukaryotic cells have a great variety of what two things?

Cell size and shape

Do eukaryotic cells or prokaryotic cells have a greater surface area to volume ratio? Why is this beneficial?

Prokaryotic.

* more efficient (better active transport)
* greater respiration rate and energy
* Have more growth
* Greater metabolism

Define Mutualism

Both benefit

Define amensalism

One harmed, one unaffected

Define commensalism

One benefited, one unaffected

Define Neutralism

Neither are affected

Define parasitism

One benefits, the other is harmed

Name 6 different groups of bacteria

* Proteobacteria
* Non-proteobacteria
* phototropic bacteria
* Spirochites
* Thermophiles
* Gram positive bacteria
* Deeply branching bacteria

Give an example of mutualism with plants

Nitrogen fixing bacteria live on root nodules of plants. Bacteria give some sugar, plants get more NH3

Define the normal microbiota of the human body

the microorganisms that coexist with humans in/on the body

What kind of relationships do microbiomes and humans have?

mostly mutual and commensalism. Can lead to parasitism

When does the microbiome begin to develop?

Birth

What are the 9 sites the human microbiome is found?

* Skin
* Scalp/outer-ear canals
* GI tract
* Nasopharynx
* Genitourinary tract
* Stomach
* Colon
* Jejunum
* Ileum

Where are the four main sterile zones of the human body?

* Trachea, alveola, bronchia tubes, lungs, sinuses
* Internal organs, Kidneys, bladder, Brain/neurons/cerebrospinal fluid
* reproductive (internal) organs
* Bones, muscle, blod

What are the advantages of microbiome?

* Protects against pathogens
* participates in metabolism
* trigger for immune system

What are the disadvantages of microbiome?

* Can be opportunistic pathogens
* Disturbed by antibiotics (superinfection), especially broad spectrum antibiotics

Viruses are not prokaryotes or eukaryotes, they are what?

Akaryotes

Viruses are obligate ____ parasites

intracellular

What are the 3 ways viruses can be transmitted?

* Bodily fluid
* Mechanical vectors
* Biological vectors

Describe how a viruses genome can be?

* DNA or RNA (can be single or double stranded)
* Linear or circular

What is the protein layer called?

Capsid

What is the cytoplasmic or nuclear membrane called?

Envelope

A naked virus doesn’t have what?

An envelope

Define spikes

Adhesion/enzymatic activities. Help with binding to membrane

What is a virion

A complete virus particle

Give the reproduction cycle of viruses

* Attachement (Grab)
* Penetration (Attack)
* Uncoating (open up)
* Biosynthesis (copy)
* Assembly (create)
* Release (Exit)

What are virus early phase proteins?

Regulation proteins

What are structural proteins?

Late phase proteins

What is endocytosis? Does it require an envelope?

Endocytic vesicle, propel virus in the cell. Does not require an envelope

What is fusion? Does it require an envelope

Spikes attach and fuse with plasma membrane. Causes cell membrane to present viral proteins/spikes. Induces an immune response. It requires an envelope.

Define budding

Capsid pushes out through exocytosis, taking part of the membrane. It can use the ER membrane or nuclear membrane. Can be via (ESCRT) or independent