Exam 2- PP 1 Nonliving Infectious Particles

nonliving infectious particles

characterizing and classifying viruses, virophages, viroids, prions

viruses do not have _, which make them unable to make proteins or ATP.

ribosomes

viruses have no _ generating mechanism.

ATP

viruses ARE _ which makes them medically important.

infectious

most viruses are _.

bacteria = friends and viruses = not!

pathogens!

DNA viruses are mostly _ stranded.

double

RNA viruses are mostly _ stranded.

single

herpes and hpv are a

huge family of viruses!

problem with chicken pox, herpes, and hpv is the fact that they can be

dormant in the body and then come back later.

hpv causes

warts on the hands + feet and cervical cancer

hpv and herpes eventually will _ from body

clear; ex- removing wart will result in a 70% chance of it not reappearing.

all viruses have

capsids.

what are capsids?

protein coats that enclose and protect their nucleic acid.

capsids are constructed from identical protein subunits called _

capsomers.

the capsid together with the nucleic acid form the _

nucleocapsid.

the nucleocapsid is composed of

capsid + nucleic acid (genome)

capsids are basically _ and _ .

protein; nucleic acids. (just missing lipids and carbs)

describe the two capsid types—

helical— continuous helix of capsomers forming a cylindrical nucleocapsid

polyhedral (Icosahedral)— vary in the number of capsomers; each capsomer may be made up of 1 or several proteins; some are enveloped meaning the membrane is outside of capsid

rabies virus is shaped like a

bullet

what are the 4 virus shapes

helical, icosahedral, enveloped, head and tail (complex)

explain helical—

• stiff or flexible

• rigid example: tubulovirus (looks like a tube)

• flexible example: ebola..why do we see the same picture over and over again? if exposed, you would catch. not many people want to catch.

the protein that makes up a capsid in a virus are called which of the following?

capsomere

explain icosahedral (polyhedral)—

• looks like a soccer ball (capsomeres)

• spike protein: peplomere

• example: adenovirus

explain head and tail (complex)—

• example: T4 phages (virus that infects bacteria)

• they can harm or help us in our gut

• can influence our health

explain enveloped viruses—

• example: herpes virus

• steals the envelope from host cell membrane

• covid = RNA enveloped virus

A

Helical virus

B

Icosahedral virus

C

Enveloped

D

(Head and tail) complex virus

what is A

phage DNA (double stranded)

what is B

bacterial chromosome

what is C

prophage

1

phage attaches to host cell and injects DNA.

2

phage DNA circularizes and enters the lytic cycle OR lysogenic cycle.

3A

new phage DNA and proteins are synthesized and assembled into virions.

3B

phage DNA integrates within the bacterial chromosome by recombination, becoming a prophage. (happens when conditions are great)

4B

lysogenic bacterium reproduces normally.

4A

cell lyses, releasing phage virions.

5

occasionally, the prophage may excise from the bacterial chromosome by another recombination event, initiating a lytic cylce.

why is resistance to environmental conditions important for an enveloped virus?

viruses with a damaged or destroyed cell envelope cannot react with the host cell receptor. anything that damages a cell membrane will damage the viral envelope. damaged = no infectivity.

viruses must be grown inside …

living cells!

compare sizes of viruses, viroids, prions, and bacteria from largest to smallest

Eukaryotes, yeast, bacteria, virus, prions, viroid

genetic drift

slowly acquire mutations so that there are different strains. ( get a booster )

genetic shift

when type of virus infects more than 1 species (flu and swine flu= genetic recombination)

DNA viruses use _____ for replication.

host enzymes.

transcription

host RNA polymerase located in nucleus

translation

DNA > RNA > Protein. uses the host ribosome!!

dna viruses steal

your stuff to do their stuff!

only DNA viruses can insert into

DNA.

____ cannot crossover with DNA.

RNA viruses. (so doesn’t affect our genomes!)

We’re constantly mutating but our body is working

against that.