Chapter 10b

Question 1

protective carrier

Answer 1

the thing that transports dna or rna
often made of protein
there is no cellular activty inside the carrier

Question 2

viruses

Answer 2

simply carriers of genetic material
their only job is to reproduce
nonliving obligate parasites
have togo into a cell to replicate and cannot reproduceoutside of cells
Many viruses are species specific meaning they bind to particular “docking” site on cells

Question 3

viruses with membranes

Answer 3

some viruses have a membrane enclsing dna or rna - most viruses that infect humans have membranes since our cells have membraces

Question 4

how do viruses cause infection?

Answer 4

cannot reproduce on their own; must enter a cell and use the cell’s enzymes and ribosomes to make more viruses

Question 5

viral replication types

Answer 5

lytic cycle
lysogenic cycle
budding

Question 6

lytic cycle

Answer 6

tkaes over the cell and makes mutliple copies; lyses the cell and releases all viruses at once by breaking open the cell

viruses make copies of itself and destroys the cell
(1. injects dna into cell 2. takes over normal cell functions to make copies of itself 3. assembles new viruses 4. lyses the cell; breaks it open to release new virus at once

Question 7

lysogenic cycle

Answer 7

inserts its dna in the dna of cell for a period of time; can go on to lytic cycle

inserts viral DNA in host’s dna and can remain there for a periodof time; viral dna is replicated when bacteria replicates; at some pointthe viral dna can come out which it then moves into the lytic cycle

Question 8

budding

Answer 8

takes over cell and makes copies; new viruses bud off the cell individually (cell continues to be a virus factory)

1. viral membrane fuses to membrane allow rna or dna to enter cell
2. rna uncoated
3. viral rna is sythesized
4. viral proteins made
5. more rna made
6. parts assembled
7. new virus”buds” off cell individually using some of cells membrane for its membrane

Question 9

AIDS

Answer 9

acquired immune deficiency syndrome

Question 10

HIV

Answer 10

human immunodeficiency virus

rna virus that uses revers transcriptase

Question 11

reverse transcriptase (RT)

Answer 11

an enzyme that reverses the transcription process, making dna from rna
instead of (dna>mrna>protein) HIV uses RT to (rna>Dna>mran>protein)

Question 12

retrovirus

Answer 12

name of HIV because it goes backward

Question 13

how HIV infects a cell

Answer 13

HIV binds to and fuses to cell membranes
(1. reverse transcriptase makes HIVdna from HIVrna 2. double stranded HIVdna is made 3. HIVdna is inserted into person’s dna and stays there 4. if HIV expresses itseld, HIVrna is made from HIVdna 5. HIVrna carries code to make and assemble HIVdna 6. HIV buds off cell)

Question 14

why is HIV so dangerous

Answer 14

1. it attacks the white blood cells that protect us against viruses (Helper T cell that directs the immune attack)
2. it can hide in the host cell’s dna for years undetected
3. it mutates rapidly - even within an individual, so it can evade the immune system and become resistant to medicines

Question 15

drug therapies for HIV

Answer 15

nucleotide analogues
reverse transcriptase inhibitors
protease inhibitor

Question 16

nucleotide analogues

Answer 16

adapted nucleotides that block reverse transcriptase from working
ex: AZT

Question 17

side effects of nucleotide analogues

Answer 17

healthy cells also take up AZT by mistake, preventing them fro dividing

Question 18

reverse transcriptase inhibitors

Answer 18

stops HIV enzyme RT from functioning (so no HIVdna is made)

we don’t havethe RT enzyme so these drugs do not effect us, little or no side effects

Question 19

protease inhibitor

Answer 19

prevens the HIV enzyme Protease from functinoing

viral cells treated with protease inhibitors “produce defective HIV, lacking infectious viral core”

Question 20

problems with treatments for HIV

Answer 20

HIV mutates rapidly (have to change medications regularly, most people have gone through most or all of the medications used to treat HIV)

drug cocktails (most people take 3-4 drugs together to attack the virus in a number of ways, expensive, toxic, 10-15 pills a day for the rest of your life)

still a very dangerous virus (we can treat hiv, but we are far from curing it)

avoid it (passes through body fluids (blood, semen, vaginal fluid, breast milk)