Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology > chapter nineteen > Flashcards

chapter nineteen Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

viruses

A

tiny, infectious particles that contain genes packaged in a protein coat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are viruses also known as?

A

obligate intracellular parasites
- can replicated only within host cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how were viruses discovered?

A

TMV (tobacco mosaic virus) in 1930s
- filtrable agents - small enough to pass through filter
- non-cellular
- crystallizable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

structure of virus

A

nucleic acid genome, capsid, sometimes envelope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

nucleic acid genome of virus

A

DNA or RNA, double stranded or single stranded
- 4 to hundreds of genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

capsid

A

protein coat or shell enclosing viral genome
- built from subunits (capsomeres)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

envelope

A

derived from host plasma membrane, contains lots of glycoprotein spikes to bind to receptors on host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

naked virus

A

doesn’t have envelope, just genome and capsid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

for which cells does the host plasma membrane not form the virus envelope?

A

fungal and plant cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

shapes examples

A
  1. spiral - TMV
  2. polyhedron - adenovirus (common cold)
  3. complex - bacteriophages (lunar lander)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

host ranges

A

limited number of host species that each particular virus can infect
- hosts identified by “handshake” between receptor molecules and glycoproteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

broad host examples

A

West Nile virus, influenza, equine encephalitis
- mosquitos, horses, birds, humans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

restricted host examples

A

HIV, smallpox, measles
- humans, particular tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

overview of virus entering host

A
  1. virus enters cell and releases viral DNA/capsid proteins
  2. host enzymes replicate viral genome
  3. host enzymes transcribe viral genome, make virus parts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

lytic cycle

A

virulent, kills host 20-40 min
1. attachment - surface proteins
2. penetration - entry of phage DNA, degradation of host DNA (hydrolyzed)
3. biosynthesis - using host’s cellular machinery to make viral genomes/proteins
4. assembly/maturation of new viruses
5. lysis - lysozymes rupture wall, 100-200 particles released

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how can viruses enter hosts?

A

injection through tail, endocytosis/fusion of envelope with PM

17
Q

lysogenic cycle

A

temperate phages, doesn’t kill host, latent/dormant stage
1. viral DNA inserted into host (provirus/prophage)
2. viral genome copied/divides with host
3. occasionally, prophage exits bacterial chromosome (lytic cycle)

18
Q

lysogenic viruses that affect humans

A
  1. HIV
  2. herpesviruses
    - herpes simplex I and II
    - chicken pox
19
Q

bacterial anti-viral defense

A
  1. restriction modification system - restriction enzymes identify/cut up foreign DNA
  2. CRISPR-Cas9 system - identify/cut DNA
20
Q

what does CRISPR stand for?

A

Clustered Regularly Interspaced Short Palindromic Repeats

21
Q

animal viruses

A
  1. attachment
  2. fusion/endocytosis
  3. uncaring - capsid removed by host
  4. biosynthesis
  5. assembly/maturation
  6. release - budding/rupture
22
Q

how are viruses classified?

A

by nucleic acid type and number of strands

23
Q

herpes viruses

A
  1. herpes simplex I (cold sores) and II (genital sores)
  2. VZV (shingles, chicken pox)
24
Q

full name HIV

A

human immunodeficiency virus

25
Q

full name AIDS

A

acquired immunodeficiency syndrome

26
Q

retroviruses

A

ssRNA to dsDNA using reverse transcriptase
- RNA to DNA to provirus in DNnA
- provirus never leaves
- dormant/inactive = only 1 in 100 HIV + has AIDS
- active = kills T helper cells of immune system

27
Q

how many plant viruses are currently known?

A

over 2,000
- most have RNA genome and helical/icosahedral capsid

28
Q

vector for plant viruses

A

pollinators, humans, insects, herbivores

29
Q

how to plant viruses spread?

A

plasmodesmata

30
Q

symptoms of plant viruses

A

blight, wilt, tumor

31
Q

viroids

A

small, circular, infectious RNA molecules

32
Q

prions

A

infectious proteins, transmitted in food, slow incubation period (10 yrs)
- not destroyed by cooking food or by acidic stomach pH
- able to cross BBB
- Mad Cow disease

33
Q

protein coding RNAs

A

mRNA

34
Q

noncoding RNAs

A

tRNA, rRNA, miRNA, siRNA, piRNA, snRNA, snoRNA and more
- many (except tRNA and rRNA are encoded in introns of protein-coding genes)

35
Q

snRNA

A

small nuclear, helps form spliceosomes and some are catalytic ribozymes

36
Q

snoRNA

A

small nucleolar, especially help assemble ribosomal subunits

Biology (35 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions