BIO 2902- BACTERIA Test 1

What is Microbiology?

The study of organisms that are too small to be observed with the un-aided eye

What can be determined by the size of Bacteria?

The diameter of bacteria does NOT change, the LENGTH does. The length of a bacteria can be determined based on the speed of growth. Faster growths means shorter lengths, vice versa.

What is the Nomenclature of Bacteria?

Genus and Species, genus is capitalized and Species is lowercase. Can be abbreviated

What is the Nomenclature of E. Coli

Escherichia coli

What is the Smallest Free-living Bacteria?

Pelagibacter ubique (0.4 um long and 0.12 um diameter)

What is the Smallest Microbe?

Nanaoarchaeum equitans (0.4 um in diameter)

Who is considered to be the founder of microbiology?

Louis Pasteur, he developed vaccines for rabies and anthrax, disproved the idea of spontaneous generation, developed pasteurization, etc.

Who postulated to prove a disease is caused by microorganisms? What were his Postulates?

Robert Koch, his postulates were:

1. Microorganisms must be found in all organisms suffering from the disease but not in healthy organisms

2. The Microorganism must be isolated from a diseased organism and grown in pure culture

3. The cultured microorganism should cause disease when introduced into a healthy organism

4. The microorganism must be re-isolated from inoculated, diseased organism and must be identical to the original microorganism

What’s the main difference between Prokaryotes and Eukaryotes?

Eukaryotes have membrane-bound organelles, and prokaryotes don’t.

What are the three domains in Life?

Eukaryotes, Bacteria and Archaea. Bacteria and Archaea are prokaryotic which is a broad term to say that they have no membrane-bound organelles.

What are the TWO types of Cellular Morphology of Bacteria?

• Bacillus - Rod Shaped (plural bacilli)

• Coccus - Spherical (plural cocci)

If a Bacillus bacteria is Curved into a comma shape, what is it called?

Vibrio

What is a Spirilla or Spirochete bacillus?

A bacillus bacteria that is long and twisted around a central axis

What are short rods/bacilli called?

Coccibacilli

How do Bacteria reproduce?

Prokaryotes in general reproduce by Binary Fission

Explain the binary division or Arrangement of Cocci bacteria dividing in SINGLE, TWO, THREE, or MANY plains

1. Cocci bacteria dividing along a Single plain are called Streptococci

2. Two Plains: tetrads

3. Three plains: Sarcinae (cubes)

4. Many plains: Staphylocci

What are the binary fission or Arrangement of Bacilli?

Bacilli forms chains. Some bacilli form extended or even branched Cells.

• Filamentous Bacteria can differentiate into substrate mycelia and vertical mycelia bearing spores (Actinobacteria Actinomyces)

• Some short Bacilli also form spores (Bacillus, Clostridium).

TRUE or FALSE: Spore bearing bacteria are Gram Positive

True: Almost all spore bearing bacteria are Gram positive.

What is the main function of the Capsule of a Bacteria?

Absorbs a lot of water to prevent desiccation

What structure aids in Bacteria to stick to something?

Fimbriae and Pilus

Which bacterial genome is used to compare others for shape and size?

The E. coli genome, circular and size of 4.5 Mbp

Where is the DNA of Bacteria stored and the size and shape of their DNA

In the Nucleoid, usually 1 circular DNA molecule but can be linear and multiple molecules. The genome size ranges from 0.7Mbp up to 12 Mbp.

What are the sizes of Ribosomes of Bacteria and Eukaryotes?

• Bacteria’s ribosomes come in 70S, 50S, and 30S sub unites

• Eukaryotes ribosomes come in 80S, 60S, and 40S.

What are the main functions of Ribosomes?

Site of protein synthesis and site of action of many antibiotics.

The ribosomes of bacteria have the same size of the Mitochondria of Eukaryotes, what is the size?

Mitochondria have a 70S size

Why doesn’t antibiotics kill us?

Due to selective toxicity, our ribosomes are a different size than bacteria so it kills bacteria more than it does us. Though some may kill the mitochondria of our cells since it’s the same size as bacterial ribosomes.

What are Inclusions and their functions in Bacteria?

usually to store materials like lipids, glycogen, proteins, polyphosphates, etc. There are also gas vacuole types which adjust buoyancy

What bacterial species produces Endospores?

Bacillus and Clostridium species

What are the functions of Endospores?

Structures found inside cells which form in response to nutrient starvation. Their function is to spore into the new vegetative cell. Spores are resistant to heat, radiation, chemicals, heavy metals, and desiccation.

true or false: modes of motility in bacteria is mostly in Bacilli forms

True: Cocci bacteria usually don’t have motility capabilities

What are the MODES of motility in Bacteria?

• Atrichous - no flagella

• Monotrichous - one polar flagella

• Amphitrichous - flagella at each end

• Lophotrichous - many pollar flagella at ONE end

• Peritrichous - Flagella insert over ENTIRE cell

What is the function of a Pili

thin protein tubes that help attach the cell to a surface or to exchange genetic material

What is contained in the membranes of Bacteria?

Bacterial membranes are typical phospholipid bilayers, contain mostly phospholipid unlike eukaryotes where its mostly proteins. The membrane consist of glycerol, a phosphate, and 2 fatty acids.

What are the Fatty Acids that make up the bacterial cell membrane

Fatty acids usually have 14, 16, or 18 carbon atoms

How can you check if a bacterial sample is alive?

you can check if it has phospholipids

How does a Glycerol molecule look like? And locate the ESTER bond?

What species produce Hopinoids?

Only Bacteria produce Hopinoids

What are the functions of Membrane proteins in Bacteria?

Function of membrane proteins include photosynthesis, respiration, ATP generation, movement of solutes, motility, sensing, DNA replication

What are the membrane permeable and impermeable to?

• Permeable: O2, CO2, glycerol, ethanol, fatty acids

• Impermeable: proteins, DNA, Amino Acids, Sugars, metal ions

What is Passive transport?

compounds enter the cell membrane with a concentration gradient. Outside of the cell has greater concentration than inside of the cell, thus molecules enter the cell with less concentration.

what is Active transportation?

moves compounds against a concentration gradient, from low concentration to high concentration. May use ATP or membrane potential (proton motive force)

What is the difference between Symport transporters vs. Antiport Transporters?

Different active transport of bacterial cell membranes.

• Symport: uses proton motive force and move a compound and a proton (H+) into the cell

• Antiport: uses proton motive force and move a compound into the cell and a proton out of the cell

What are the functions of Efflux pumps?

uses ATP to transport toxic compounds out of the cell, such as antibiotics and anti-microbial natural products

What are the Bacterial cell walls like compared to cell walls of plants?

cells walls in bacteria are rigid and strong enough to resist osmotic pressure, and is external to the cytoplasmic membrane. It is composed of a biomaterial found only in Bacteria called Peptidoglycan

What enzyme in our bodies break down the Peptidoglycan membrane of Bacteria?

Lysozyme in our eyes and saliva

What are is the Peptidoglycan composed of?

Composed of long chains of 2 sugars: NAG (N-acetyl glucosamine) and NAM (N-acetyl muramic acid).

Its a repeating dimer of NAG-NAM-NAG-NAM-NAG

Attached to the NAM (n-acetyl muramic acid) is a short peptide composed of?

4 amino acids: L-alanine, D-glutamic Acid, AAx, and D-alanine. From beginning to end.

What is the Glucose molecule look like and its formula?

C6H12O6

Between the NAG and NAM chain of peptidoglycan, what is the bond that holds them together called?

How can you identify a Gram-positive Bacteria?

They have a thick peptidoglycan layer, up to 80nm, and no out membrane. They also contain teichoic acids in the cell wall and very small or absent periplasm

How can you identify a Gram-Negative Bacteria?

They have a thin peptidoglycan layer, 1-3 layers, and possess an outer membrane. Do not contain teichoic acids in their cell wall and have a LARGE periplasm between the inner membrane and outer membrane.

In a Gram-negative bacteria, it contains a membrane that gram-positive bacteria do not have. What is it and its composition?

Gram-negative bacteria contain an Outer membrane composed of mostly asymmetric phospholipid membrane.

The outer leaflet of the outer membrane contains lipopolysaccharide (LPS)

• which is composed of Lipid A, core polysaccharide and the O antigen.

What is a Marker for a Gram-negative bacteria?

within the LPS of the leaflet of the Outer membrane, is Lipid A which is attached to a Core polysaccharide composed of 5-10 sugars including a KDO which is the marker for gram-negative bacteria

What is the Glycocalyx?

In gram-negative bacteria, it is a extracellular polysaccharide or protein which surrounds the cell.

• If loosely attached its called Slime layer

• If firmly attached its called the a Capsule

Function is to prevent phagocytosis by immune system macrophage and aids in attachment or prevention of desiccation.

Differentiate between Archael ether vs. Bacterial ester linkage

What are the parts of Archael Ribsomal RNA?

• 16S small subunit

• 23S and 5Ss large subunit

• (some additional 5.8S large subunit in eukaryotic)

What does Archaea use to replicate DNA and what is it similar to?

Archaeal proteins involved in DNA replication, transcription are more similar to Eukaryotes than Eubacteria

True or FALSE: Archaea have peptidoglycan like Eubacteria?

False: there is no peptidoglycan in Archaeal cell walls, but some Archaea contain pseudomurein in their cell walls

What are the 2 major Phyla of Archaea?

• Crenarchaeota

• Euryarchaeota

Differentiate phyla Crenarchaeota

• Known strains are thermophylic or hyperthermophilic (grows in high temperatures) and usually acidophiles. Very widespread uncultivative representatives.

Differentiate Phyla Euryarchaeota

• Widespread and diverse phyla that are Methanogens (strict anaerobes that convert CO2 and H2 or C1 compounds such as formate and methanol into Methane CH4)

• They are also extreme halophiles and Thermophiles

What species of Archaea is thought to where Eukaryotes originated from?

Heimdallarchaeota

What are Viruses?

obligate intracellular parasites that require a host to reproduce by using proteins and energy. Usually very small from 28nm to 200nm.

What’s the Largest known virus?

Mimivirus 750nm

True or False: All viruses contain genetic material DNA and RNA

FALSE: All viruses do have genetic material but EITHER DNA OR RNA, never both

Where is the genetic material contained in Viruses?

Their genome is enclosed in a protein shell called the CAPSID. The genome plus the capsid is called Nucleocapsid.

What are Enveloped Viruses?

Some viruses have a host-derived membrane enclosing the nucleocapsid (enveloped viruses)

If viruses that do not contain a host-derived membrane, what are they called?

Naked Viruses

EXAM QUESTION: How many sdides does an icosahedron have?

20 sides

Explain the geometry of Capsids of Viruses

composed of multiple copies of one or more capsid proteins (capsomers) that form a geometric arrangements such as icosahedron, helix, combinations of the two.

What is Host or Tissue trophism?

When the protein of the capsid of viruses binds to a protein or glycoprotein on the host cell and allows the virus to recognize and bind to the host. This explains why you can get sick but your dog can’t catch the same sickness.

Explain Uncoating in Viruses

the genome leaves the capsid and enters the cytoplasm or moves to the nucleus of the host cell

Explain Transcription of Viruses?

The genome of the viruses is transcribed into the genome of the host cell for replication. It is easy for dsDNA or dsRNA or positive strand ssRNA. But for negative strand ssRNA, they must convert to positive strand RNA

What are the two ways viruses do to their host after replication?

1. Lyses cell

2. Integrate genome into the cell

What are Temperate Bacteriophage?

Genome of phage integrates (cuts and inserts into) the bacteria’s own genome.

• No production of viral mRNA or proteins, no virions.

If a virus detects that the host cell is compromised, what does it do?

If detected, it reproduces phage genome and capsid proteins. Also assembles virions. Then lysis of host cell

What is a virion?

a complete, infectious virus particle that exists outside of a host cell

What are the Composition of Bacteria based on Polymers?

E. coli is used for major comparison: based on percentage%

Differentiate the different energy sources of Bacteria

• Phototrophs: utilizes sunlight

• Chemotrophs: bacteria that oxidise organic or inorganic compounds

What are Nutritional Types?

defined by energy, carbon, and hydrogen/electron (H/e-) source of energy.

What are the Nutritional types of Bacteria?

Most bacteria fall into One of 4 Classes:

• Chemolithotrophic autotrophs

• Photoorganotrophic heterotrophs

• Photolithotrophic autotrophs

• Chemoorganic heterotrophs

What is the Carbon Source?

when autotrophic fixation of CO2 is an energy consuming process which is mostly restricted to photosynthetic bacteria. The process is called Calvin Cycle

What species can Fix atmospheric nitrogen for it to be used?

• Free-living bacteria (Cyanobacteria, Klebsiella)

• Symbiotic Bacteria (Rhizobium)

How is Atmospheric Nitrogen fixed?

In Nitrogen Source. NO3 or NO2 is reduced to NH3 by many bacteria where it is then assimilated into cellular material. Example: NH3 → Glutamate → Glutamine

What are some Growth factors needed by Bacteria?

Growth Factors: preformed organic compounds which are required by the cell for growth but which cannot be synthesized by the cell.

example: Vitamins, Amino acids, Purines/Pyrimidines, sometimes specific fatty acids

What does Fastidious mean?

If a bacterium requires many growth factors. Example: many lactic acid bacteria and streptococci are very fastidious.

They may require many or all the vitamins and many amino acids

What metal element is needed for Bacteria to grow?

Bacteria require large amounts of iron in the form of Fe+2 (ferrous) to grow.

What are Culture Media used for?

it gives us the ability to culture or grow bacteria. Many functions such as to isolate pathogens, material for research, or industrial microbiology.

What is a Defined Media?

It is a culture where all the ingredients are known, such as the chemicals defined. Must know the entire and precise nutritional requirements of the bacteria to grow.

What is a Complex Media?

The ingredients are not known in a precise, chemically defined way. It provides all nutritional requirements even if the bacteria don’t need them. It’s useful for fastidious bacteria

What is Glycolysis?

An almost universal pathway for utilizing carbohydrates, conversion of glucose to pyruvate. Energy is released by the oxidation of glucose conserved by substrate level phosphorylation and by the production of reduced NAD (NADH).