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Difficult Topics Covered So Far-Bio Cheat Sheet (DRAFT) by

Bio Lecture 5 Notes

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Viruses

Obligate intrac­ellular parasites: Required to reproduce within a host
- Always requires ribosomes from host cell
Retrov­iru­s-HIV
Antigenic Drift v. Antigenic Shift
relating to Influenza
--->Huge genome section rearranged
---->Changes host range
this is how they think HIV first evolved from monkeys
Influenza is a -ssRNA Virus
Infection Cycle
Does it encode for its own polyme­rase?
- Minus sense RNA cant be read as RNA
- Host cells dont have an RNA dependent polymerase so virus has to bring it in to transform the minus into a plus
1. HIV enters host cell and rleases the capsid and RNA strands
Does it carry its own polyme­rase?
-Minus cant be read as mRNA, so we have to switch to a plus....Minus ssRNA has to bring the protein in to make the other RNA
- Plus ssRNA can be read as mRNA so it encodes instead of carries
2. The viral RNA gets Reverse Transc­riptase attached to it so that it can start to be read as RNA-DNA hybrid, which is the same as the host cell DNA
Antige­netic Drift
- over time the virus genes are going to start to drift and change because it will start to accumulate mutations
NOT DRASTIC
3. New incognedo viral RNA enters the nucleus and gets replicated along with the host cell DNA
Antigenic Shift
- a new virus subtype is created because of a superi­nfe­ction which is viral dna reassortment
-DRASTIC CHANGE
most common in flu
*Retro virus is positive but works different because it carries into the cell reverse transc­riptase which makes RNA go back to DNA
--> Creates undercover spy to get replicated with host DNA
H1N1 and H3N2 both able to penetrate organism. Both at same time so genes will rearrange and mesh/recombine
--> Create virus strain of H1N2
A graduate student in a virology lab sends the genome of a novel virus for sequen­cing. Upon the return of the sequence, the student analyzes the genome and notices there are no polymerase genes. Due to this result, she concludes that it is a: dsDNA virus

Nutrient Aquision

Diverse Group
Energy Source
Photot­rophs
(light)
Chemot­rophs
(chemi­cals)
-->1. Organic (chemo­org­ano­trophs)
-->2. Inorganic (chemo­lit­hot­rophs)
Carbon Source
Autotrophs
Hetero­trophs
(only from organic matter)
Bacteria can be any combin­ation of the above
Humans are Chemoo­rga­noh­ete­rot­rophs
Their metabolic abilities are very different than all other organisms so they can survive in crazy places (bacteria)
Fungi are decomp­osers. They get everything they need from organic matter.
chemoo­rga­noh­ete­rot­rophs
 

Bacteria

 
Biofilms
 
- a group of microo­rga­nisms that stick together to a surface.
 
Biofil­ms/­bac­teria are studied in a controlled lab setting sepera­tely, but they mix together in nature
 
Bacteria live in commun­ities and it is stable
 
The arrang­ement of commun­ities are the biofilm. they attach themselves to a place with nutrients and then secrete jelly matrix and then the others start to join
 
All different kinds of bacteria together!
-->antibi­otics dont function with these structures because they cant penetrate the entire structure.
- biofilm forms holes and uses the pressure for nutrients and dispersion
 
If the mitoch­ondria and chloro­plasts in eukaryotic cells resulted from endosy­mbi­osis, what features might we expect these organelles to contain?
a plasma membrane, DNA, and ribosomes

Fungi

Absorptive Feeding
Life Cycle
1. Hypha secrete digestive enzyme
1. Plasmogamy (fusion of cytoplasm)
2. Break down into organicc compounds
2. Hetero­kar­yotic Stage
-- Cytoplasms fuse together but not the nuclei (not diploid or haploid)
3. Reabsorbed back into hypa
3. Nuclei fuses only diploid part of the lifecycles (2n)
4. Water follows by osmosis
- Pressure increases and pushes molecules through structure to relieve pressure
4. Divide and reproduce by spores get relocated to enviro­nment where they thrive
One of the charac­ter­istics is that they have hypha that grow very quickly (function)
--->form: thin filaments dont need a lot of energy and have lots of surface area to absorb nutrients
5. Grow into mycelium
a. Can either produce spores on its own and reprod­ucing them (asexual)
-Just depending on mutations for gene diversity
b. Can fuse with another one and start cycle over to create genetic diversity
Monoph­yletic: group that contains all descen­dants of a common ancestor

Protists

Diverse evolut­ionary lineage
Giardia
the Creepy Happy Parasite
Contains two nuclei
Same DNA content
- Same time of replication
- Same transc­rip­tional activity
Lacks mitochondria
- Has mitoch­onrial remnanr
- Relies primarily on glucose as energy source
Two forms
- Motile flagellated
- Non-motile cyst
Giardia infection is the most frequently diagnosed intestinal parasitic disease in the United States
The Ciliates
Have two types of vacuoles
-Food Vacuoles
-- Digestion of food{{nl-Contractive Vacuoles
--Regulation of water balance
Amoebas
Tubulinids
Slime Molds