Medical Microbiology exam 1

Eukaryotic, bacteria, and Archaea

What types of organisms that study by microbiologist?

Bacteria, Archaea, Eukarya

What is on the tree of life and where protozoa fall on it?

it’s where on organism origin from and protozoa fall in the Eukarya

Where microorganisms/infectious agents fall on the tree of fall?

In bacteria and Eukarya

What type of microbes that can cause disease?

• Fungi (yeasts & molds)

• Parasite (Protozoa, Helminths)

• Bacteria

• Viruses

What are structures do eukaryotes cells have?

• Cell membrane

• Golgi Apparatus

• Nucleus

• Ribosomes

What are structures do Prokaryotes cell have?

• Lack a Membrane-bound nucleus

• 70s ribosomes

• Cell wall

• Nucleoid

• Plasmids

• 
  

What are some differences between prokaryotes and eukaryotes?

• Prokaryotes lack cell-bound organelles but eukaryotes do have cell-bound organelles

• Prokaryotes can only be unicellular but eukaryotes can be both

What are some similarities between prokaryotes and eukaryotes?

• Both can cause disease

• have a cell membrane, ribosomes, cytoplasm, and DNA

What is the size of a protozoan parasite?

Skittle ( intracellular)

Red vine (extracellular)

What is the size of a Fungus

M&M

What is the size of a bacteria?

M&M ( large)

Tic-Tac ( small)

What is the size of a virus?

• Sprinkles (large virus)

• Grain of sugar (Small virus)

What kind of cells are protozoa?

Eurkaryotes

What do ALL protozoa have?

• Nucleus

• Mitochronia

• Ribsomes

• Cell membrane

What is a pellicle and what its composition?

Its inside of the plasma membrane that add rigidity

its a band of proteins

How do some protozoan reproduced?

• Sexual ( Gametocyte = sexually reproducing form )

• Asexual

• 1. Binary Fission: grows larger divides in two

• 2. Budding: smaller daughter cell pinches off of larger mother cell

• 3. Schizogony/Multiple fission: nucleus divides mutiple times and

Why do some Protozoa form cysts?

• protect against unfavorable environmental changes

• site of nuclear reorganization or cell division

• allows transfer between hosts

What is the formation of cyst in protozoa?

• Encystment ( forms cyst)

• excystment (occurs when conditions are favorable growth)

What are the three types of motility of protozoa?

• flagella

• Cilia

• pseudopods

What are characteristics of ALL fungi?

• Eukaryotes

• Cell walls (different from plant cell walls, can contain chitin, glucan, mannan)

• Cell membrane (contain ergosterol0

What are characteristics of some fungi?

• Multicellular

• Unicellular ( Yeast)

• Spore formation

• Hyphae

How does yeast reproduce?

Asexually through budding but can sometimes reproduce sexually

What is dimorphism in terms of fungi?

Temperature can affect the form of a fungus ( Two forms)

• In cooler temperatures can appear as mutilcellular while hot temperatures can appear as yeast

How do overall fungi reproduce?

• sexually through spores ( producing genetic identical offspring to be dispersed in new locations) or have two nuclei fusing into one

• asexual through budding

How do fungi get there nutrients?

• through soil

• through break down of carbs ( chemoheteroph)

• dead things ( saprophyte)

What are the composition of the fungi cell wall?

chitin

What are hyphae made of?

• filaments

• multiple hyphae called mycelium

• chitin

How are protozoan cysts, Fungal spores, bacterial endospores similar?

• All are formed when they need to be in different environments

• Cysts and endospores are formed when it needs to be survive (environments are not favorable)

• Spores are used for reproduction/growth

What is Cyclospora?

• Protozoan parasite

• only human host

• causes explosive diarrhea that lasts for 10-12 weeks (untreated)

• testing requires stool samples

What is Yersinia pestis?

• gram-negative bacillus-shaped bacterium

• in domesticated, urban, and wild animals

• when transmitted by flea cause bubonic plague ( swollen hard, red painful lymph nodes)

• transmitted by direct contact with infected animals

• if in airways pneumonic plague

What is Giardia?

• Flagellated protozoan parasite

• habits health GI host

• present soil, water, or food contaminated with feces

• cause severe GI distress

What is Coccidioides immitis or valley Fever?

• soil-dwelling fungus

• transmitted by air borne spores

• experiences headaches, fever cough, SOB, fatigue, muscle aches, rash

• resolves on its own but ppl with HIV, pregrant, diabetic, black or filipino should recevie treatment

What is Plasmodium sp.

• intracellular protozoan parasite (non-motile)

• spread by female mosquitos

• rupture RBCs which cause fever, infects liver cells & infects RBC

• causes malaria

How are archaea similar to bacteria?

• Prokaryotes

• Have cell walls but archaea don’t have peptidoglycan

• highly resistant to their environment

Where do Archaea live?

They live in extreme environments

1. Thermophiles ( hot)

2. Halophiles (salty)

3. Methanogens (produce methane gas)

how does Archaea climate change affect?

Since some live in GI system the can produce methane which producing greenhouse gases

what are the shapes of Bacteria

1. Coccus

2. Coccobacillus

3. Vibrio (bent rod)

4. Bacillus

5. Spirillum ( zig-zag)

6. Spirochete ( crowscrew)

Strepto = multiple/Chain

Staphyl = cluster

What is the function of the bacterial cell wall?

• maintains shape and rigidity

• protects form cell osmotic lysis ( taking in too much water)

• can contribute to pathogenicity

What is the composition of a bacterial cell wall?

• Peptidoglycan (PGN)

• LIpoteichoic acids

• Lipopolysaccharides (LPS)

What is PGN made out of?

• NAG( N-acetylglucosamine)

• NAM ( N-acetylmuramic acid)

• tetrapeptide side chains

What are three types of cell walls?

• Gram-positive ( purple, thick layer of PGN 60-90%)

• Gran-negative ( pink, thin layer of PGN 10-20%)

• Acid Fast

• No cell wall

What is the outer membrane called of a gram-negative cell wall?

lipopolysaccharides (LPS) (made out of carbohydrate: head and lipid: tails)

• relatively impermeable

What bonds the PGN to cell membrane in gram-positive?

lipoteichoic acids

What are the difference between cell walls and cell membranes?

1. Composition

• Membrane made out of phoslipid bilayer

• Wall made out of PGN

2. Function

• Membrane: controls what goes in and out

• Cell wall: protects cell

3. Location

• Membrane on the outside

• Wall is outside of membrane

How does the cell wall protect the cell from lysis?

when water flows in it limits the cells flexibility

What are acid-fast bacteria cell wall made out of?

• considered gram-positive but poorly stained

• made out of 60% of lipid (mycolic acid) which makes it waxy

• ex: mycobacterium

What is the example of bacteria without cell walls?

Mycoplasma

• have sterols in cell membrane for stability

What are L-forms?

bacteria that normally have a cell wall can lose their ability to form it

• can be cause but chronic/recurrent infections that are difficult to treat

• ex: mycobacterium

Why is it hard to treat bacteria without cell walls?

certain antibiotics target the making of PGN or cell wall

What is the difference between the Mycobacterium and Mycoplasma?

Bacterium: acid-fast cell wall but can lose its ability to form it

Plasma: no cell wall ever

What is so special about the horseshoe crab?

The injection of the blue blood the horseshoe crab (Limulus test) which helps endotoxin which is produced they presents of Lipopolysaccharides (LPS).

What is endotoxin shock?

• septic shock

• Blood vessel vasodilate causing blood pressure to drop, poor circulation, poor oxygen delivery, shutting organs down, death

What is a Glycocalyx

slime layer (thin more secrete stops from drying out) or capsule (more tight provides protection from) of bacteria

What is composition of Fimbriae and pili?

proteins

• help attach to surfaces

What types of flagella placement?

1. amphitrichous (both send ends)

2. Peritrichous (all over)

3. monotrichous ( one end)

4. lophotrichous ( lump one end)

Why causes run & tumble in bacteria?

• Chemotaxis

• Phototaxis

• Thermotaxis

• Aerotaxis

• Osomtaxis

What is Axial Filaments in Spirochete?

• found in cell wall in periplasmic space

• help do the crowscrew motion

What is bacteria chromosomes vs. plasmids?

• Chromosomes circular single DNA

• Plasmids circular, replicate independently carries non essential information

What is difference bacterial ribosomes and Eurkarytoe ribosomes?

Bacteria: 70s

Eukaryote: 80s

What the two bacteria that endospores that are medically important?

• Clostridium

• Bacillus

Tetaus is examlpe

What five things that bacteria cause disease?

1. Get in host

2. stay in host

3. grow in host

4. avoid immune response

5. Damage/disrupt toxin & enzymes

What are the structures help bacteria cause disease?

cell wall

What are secrete mocules bacteria to cause disease?

• enzymes

• Toxin

What is a A -B toxin?

B binds to target cell

A component agitates or disrupts the function of target cell

What are factors of virulence?

toxin & enzymes

What is the genome location & what is its composition?

• Nucleic Acid

• found in core of virus

• May be DNA or RNA

  
  

What is the capsid and its composition?

• made out of capsomeres which made out of proteins

• surrounds the genome

What is a envelope?

• lipid bilayer from the host cell in which the virus produced

What do spikes and what’s its composition?

They help attachment to host cells and made out of protein

What are the shapes of viruses?

helical, polyhedral, complex

Why viruses are not considered to be alive?

to be alive they have to growth, self-replication, responsiveness

They CANT replicate independently, carry out metabolism or make ATP

What are the five steps in viral replication that are common to ALL viruses?

1. Attachment

2. Entry/penetration & uncoating

3. Synthesis

4. Assembly

5. Release

What is attachment in viral replication?

virus attach to host cell using capsid proteins ( naked virus) or spikes (enveloped)

What is entry/penetration of viral replication?

• naked virus insert genome into host cell

• enveloped viruses fusing their envelope into host cell’s membrane

What is synthesis in viral replication?

They need ribosomes to make and nucleic acids make DNA & RNA

What is assembly in viral replication?

DNA might get packaged into the viral capsids and then be delivered to a new host cell (transduction)

What is release in viral replication?

• release viruses from host cell by budding

• this can kill a host cell