Biology 3053 Midterm Review

Microbiology

Study of living organisms that you cannot see with the naked eye.

Opportunistic Infection

Caused by pathogens that take advantage of an opportunity not normally available.

What circumstance would allow for an opportunistic infection to occur?

Host with a weakened immune system.

What are the 3 Domains of Life?

Eukarya, Archaea, Bacteria.

What's the usual size of bacteria?

2-8um x 0.2-2.0um

True or False: Bacteria are eukaryotes.

False

What are the possible shapes of bacteria?

Bacillus, Coccus, Spiral.

Prokaryotes

Genetic material not enclosed in a special nuclear membrane.

What are the cell walls of bacteria composed of?

A carbohydrate & peptidoglycan.

How does bacteria reproduce?

Binary fission

What does Staphylococcus aureus cause?

Foodborne illness (gastroenteritis) and skin/wound infections.

What does Streptococcus pyogenes cause?

Strep throat, scarlet fever & necrotizing fascitis.

True or False: Archaea are prokaryotic.

True

Is peptidoglycan in the cell wall of archaea?

No

Which domain is found in extreme environments?

Archaea

Does archaea cause disease in humans?

No

What are the groups of Archaea?

Mathanogens, Extreme Halophiles, Extreme Thermophiles.

What does the Domain Eukarya consist of?

Protozoa, Fungi, Plants, & Animals.

What is an example of a unicellular fungi?

Yeast

What is an example of a multicellular fungi?

Mushrooms

What is the cell wall in fungi composed of?

Chitin

What are the visible masses that mold form?

Mycelia

What is each filament that forms mycelia called?

Hyphae

What is found in water, moist environments?

Protozoa

How do Amebae move?

By extensions of their cytoplasm known as pseudopods.

Numerous shorter appendages on protozoa are known as ________________.

Cilia

True or False: Parasitic flatworms and roundworms are multicellular.

True

What are the 2 Phyla that Parasitic worms are divided into?

Platyhelminthes (flatworms) and Nematodes (roundworms)

What is the average size of a virus?

20-1000nm in length

True or False: The core of a virus contains both RNA & DNA.

False

Are bacteria cells eukaryotic or prokaryotic?

Prokaryotic

What are human cells?

Eukaryotic

How big are eukaryotic cells?

10-100 micrometres

What is the purpose of histones and what cell are they found in?

In eukaryotic cells they organize and compact the DNA

Sarcinae refers to what?

Cell morphology like a cube

What is the function of a plasmid?

Contain genes that are not required by the cell, however they are beneficial for survival. Antibiotic resistant genes are located here.

When are capsules seen?

In negative staining

What do capsules do?

Firmly adhered to the cell wall, they protect the cell from phagocytosis.

Biofilm

A microbial community that usually forms as a slimy layer on a surface.

Glycocalyx

Thick outer covering of the plasma membrane.

Extracellular polymeric substance (EPS)

A glycocalyx that helps cells in a biofilm attach to target environment and each other.

Virulence

The severity or harmfulness of a disease or poison.

Peritrichous

Flagella all around bacteria.

Monotrichous & polar

One flagella at the end of bacteria.

Lophotrichous & polar

Multiple flagella at the end of bacteria.

Amphitrichous & polar

Multiple flagella at both ends of bacteria.

What protein is the filament made of?

Flagellin

What is the basal body responsible for?

Movement

What is clinically important for identification of different types of gram-negative bacteria?

H Antigen

What does Treponema pallidum cause?

Syphillis

What does Borrelia burgdorferi cause?

Lyme Disease

Fimbriae and pilli are found in what type of bacteria?

Gram-negative

Why are fimbriae important for virulence?

They allow for adherence to each other and other surfaces such as epithelial cells.

What is the major function of a cell wall?

To prevent a cell from lysis in a hypotonic environment.

What is found in bacterial cell walls?

Peptidoglycan

How do tetrapeptides differ in gram-negative and gram-positive bacteria?

In gram-negative they are directly linked to each other, however gram positive they are linked by a peptide cross-bridge.

Why is peptidoglycan important?

Needed for cells to grow and divide.

Periplasm

A gel-like fluid between the outer membrane and the plasma membrane

What does the periplasm contain?

Degradative enzymes & transport proteins

What is the outer membrane of a gram negative cell made of?

LPS (lipopolysaccharide), lipoproteins & phospholipids.

What is the importance of Lipid A?

Endotoxin; embedded in top layer of OM.

What is the importance of the core polysaccharide?

Provides stability

What is the importance of the O polysaccharide?

Used for identification & classification of bacterial species.

What happens when alcohol is applied to a gram-positive stain?

Dehydrates the peptidoglycan and the crystal violet cannot exit.

What happens when alcohol is applied to a gram-negative stain?

Dissolves OM and the crystal violet exits.

What is the smallest known bacteria that can replicate outside living host cells?

Mycoplasma

Sterols

Found in plasma membranes to help prevent them from lysis.

What is mycobacterium stained with?

Carbolfuchsin

Lysozyme

An enzyme found in tears, perspiration, mucus & saliva.

What enzyme is responsible for breaking the bond between NAG & NAM?

Lysozyme

What type of antibiotic interferes with the formation of the peptide cross bridges in peptidoglycan?

B-Lactam

Plasma Membrane

Serves as a selective barrier through which materials enter & exit the cell

What has a phospholipid bilayer?

Plasma Membrane

Plasmids

Small, circular DNA molecules that aid in antibiotic resistance and can be transferred from one bacterium to another.

What is found in certain gram-positives and is very resistant to heating, drying & toxic chemicals?

Endospores

What is responsible for the heat resistance in endospores?

Diplicolinic acid

What do endospores contain?

Diplicolinic acid & Calcium

Vegetative Cell

a cell of a bacterium or unicellular alga that is actively growing rather than forming spores.

How does the cell wall in a eukaryotic cell differ from a prokaryotic cell?

No peptidoglycan.

What are fungal cell walls made of?

Chitin

What do animal cells not have?

A cell wall

Pellicle

Flexible outer covering in protozoa.

What is one way for substances to enter cells in eukaryotics but not in prokaryotics?

Endocytosis

Phagocytosis

Pseudopods engulf particles and bring them in

Pinocytosis

Allows cells to internalize extracellular fluid

Receptor-mediated endocytosis?

Materials are imported using specific receptors

What is the fluid portion of cytoplasm referred to as?

Cytosol

What is the site of protein synthesis?

Ribosomes

What are the two subunits of ribosomes in prokaryotic cells?

50S and 30S

What are the two subunits of ribosomes in eukaryotes?

60S and 40S

Which has larger ribosomes, eukaryotes or prokaryotes?

Eukaryotes

Rough ER

Manufactures proteins for secretion and membrane proteins such as glycoprotein

Smooth ER

Functions in the synthesis of phospholipids, steroids and fats.

Endosymbiosis

The relationship in which one organism lives within another.

Growth in biology refers to __________________.

An increase in the number of bacterial cells

What are the physical requirements for bacterial growth?

Temperature, pH and correct osmotic environment.

Psychrophiles are _____________.

Cold Loving. Grow from -10 to 20 degrees Celsius. Optimal temperature is 15 degrees Celsius.

Psychrotrophs are responsible for what?

Food Spoilage

What temperature do psychrotrophs grow in?

0-30 degrees

Mesophiles optimum temperature is?

25-40 degrees Celsius.