kingdoms, viruses, pathogens

Question 1

do bacteria have chloroplasts

Answer 1

no

Question 2

Transcription/translation occurs in same compartment of ___ everyone else does it in diffferent compartmetns

Answer 2

bacteria. note that even protists do transcription and translation in diff compartments

Question 3

what component is in cell walls

Answer 3

peptidoglycan

Question 4

flagella in eukaryotes vs bacteria

Answer 4

9+2 for cilia /flagella in eukaryotes, protists, plantae. Bacteria have their own special flagella- rotary motor

Question 5

three domains of living things

Answer 5

bacteria, archae, eukarya

Question 6

Pathogen

Answer 6

something that causes a disease

Question 7

Archaea

Answer 7

primitive type cells. Different enough that they are NOT closely related to other bacteria- but they ARE prokaryotes. No nucleus. Also called ‘extremophiles’ because they like to live in hot springs, glaciers, etc. no effect on health/disease. Own kingdom.

Question 8

explain how ancestral eukaryotes evolved

Answer 8

an archae type picked up a mitochondria . Gives rise to fungi, animalia, etc. the archae that picked up photosynthetic bacteria became chloroplasts-> plants, protists

Question 9

how many kingdoms are there

Answer 9

6

Question 10

why are viruses not living?

Answer 10

They MUST be inside of a host cell to replicate- cannot do it on their own.

• Have no metabolism
• No oxygen consumed, no ATP used, etc

Question 11

lifecycle of a phage- lytic vs lysogenic?

Answer 11

• Once DNA has been injected, could go a couple of ways
• Lytic cycle: take over cell right then and immediately start transcribing/translating viral genes. breaks open host cells
• Lysogenic cycle: turn off repressor proteins, repressor protein says ‘don’t break open!’- has potential to be converted back into viral factory stage. Has potential to break open and produce new virus.

Question 12

replication cycle DNA virus

Answer 12

1) Attachment (Adsorption)
2) Penetration
3) Uncoating
4) Targeting
5) Gene expression.
- synthesis of viral mRNA (transcription)
- synthesis of viral proteins (translation)
6) Genome replication
7) Virion assembly/maturation
8) Release of new infectious virus
- lysis : breakdown of cell membrane and release of virus
- budding: viruses “bud” through cell membrane and are released without necessarily killing the cell. Viruses acquire envelopes (membranes) during this process.

Question 13

Replication cycle for RNA virus

Answer 13

• Carries its own reverse transcriptase- so it can copy its own RNA and animal cells do not have any reverse transcriptase in them
• Note: reverse transcriptase critically important in cloning as it creates cDNA. It’s the only enzyme that will use RNA as a template. Howard Temin + David Baltimore Nobel prize for this.
• Binds 2 cell. HIV viruses only attack T-cells. Have marker on surface called CD4. It’s the surface marker that hiv viruses recognize in order to bind to target cells.
• Copy RNA into double stranded dna. Why? Much more stable
• Double stranded dna inserts itself DIRECTLY INTO GENOME OF HOST CELL.

Once in host genome; transcription of DNA produces RNA’s that are the genome for an RNA virus. Same RNA gets translated by ribosomes and makes viral proteins, assemble new viruses, and then bud out.

Question 14

difference between DNA virus vs RNA virus replication: genome

Answer 14

DNA virus not incorporating itself into genome

Question 15

why do RNA viruses carry their own reverse transcriptase with them?

Answer 15

so it can copy its own RNA- animal cells do not have any reverse transcriptase in them

Question 16

what marker would you use to test for HIV?

Answer 16

CD4

Question 17

mutation in CCR5 protein- what is it and what does it lead to?

Answer 17

no functioning CD4 receptor for the virus to hook onto- totally HIV resistant (if homozygous)

Question 18

common tests for HIV

Answer 18

• t-cell count
• virus titer (count # viruses)
• western blot (southern blot with proteins) use anti HIV antibiotics to detect gp120 (envelope protein) sits on surface. Direct test for nucleic acid.
• Can also detect patient antibody against gp120: if they’re making antibody, it means they have been exposed

Question 19

treatment for HIV

Answer 19

• AZT- azidothymadine- form of nucleotide that is dideoxy- has an amino group instead of 3’ OH group. Synthesis of DNA will STOP at dideoxy. Just like it did in some sort of sequencing reaction we were discussing.
• The reason it is so efficient at interrupting the RNA virus is that Reverse transcriptase has a higher affinity for AZT (as opposed to normal thymine) azt is just a mutated form of thymine.

Question 20

what is combination therapy for HIV?

Answer 20

AZT + protease inhibitors (prevent resistance to AZT) . inhibits manufacture of new HIV viruses

Question 21

three types of bacteriophages

Answer 21

Lamba phage , T2, T4

Question 22

list out some common manifestations of the herpes virus (DNA) group

Answer 22

herpes, cold sores, chicken pox, epstein barr,

Question 23

cancer causing (DNA) viruses?

Answer 23

HHV, karposi’s sarcoma. Also cervical cancer comes from papilloma virus.

Question 24

give some examples of RNA retroviruses

Answer 24

HIV, polio, yellow fever

Question 25

rabies/mumps/measles/flu/ebola/hep C- all what type of virus?

Answer 25

RNA virus

Question 26

herpes: RNA or DNA virus?

Answer 26

DNA

Question 27

influenza: DNA or RNA virus?

Answer 27

RNA

Question 28

prion diseases

Answer 28

brain issues- proteins fold into the wrong shape- due to infection via prion, which is NOT a virus but behaves like one