Week 1: acellular microbes

Question 1

capsids

Answer 1

large macromolecular structure which protect genetic material and aids transfer between host cells

Question 2

helical capsids

Answer 2

shaped like hollow tubes with protein walls, promoters self assemble

Question 3

Entry to host cell for enveloped viruses

Answer 3

membrane fusion at cell surface or receptor mediated endocytosis followed by membrane fusion

Question 4

Entry to host cell for non enveloped viruses

Answer 4

receptor mediated endocytosis or direct injection of nucleic acid

Question 5

replication in DsDNA virus

Answer 5

in host cell nucleus using host cell DNA polymerase (not poxviruses and bacteriophage)

Question 6

replication in SsDNA viruses

Answer 6

must convert ssDNA to dsDNA

Question 7

Replication in RNA viruses

Answer 7

must use virally encoded enzymes to replicate genome

Question 8

which viruses carry RNA dependent RNA polymerase

Answer 8

dsRNA and -ssRNA

Question 9

role of envelope proteins

Answer 9

involved in viral attachment to host cell

Question 10

virophage

Answer 10

viruses that infect other viruses

Question 11

satellites

Answer 11

nucleic acid enclosed in a protein shell, lack genes that code encode for functions needed for replication, requires a helper virus for replication

Question 12

Viroids

Answer 12

Composed of closed circular ssRNAs, do not encode gene products, replication requires host cell, cause plant disease

Question 13

Prions

Answer 13

infectious proteins, abnormally folded version of normal proteins which cause normal proteins to change conformation causing a loss of neurons in brain

Question 14

LUCA

Answer 14

last univeral common ancestor
was likely an anaerobe
lipid membrane surrounding nucleic acid genome
endosymbiotic event between archael cell and a bacterium led to evolution of eukaroyotes

Question 15

endosymbiotic event mitochondria

Answer 15

from proteobacteria

Question 16

endosymbiotic event chloroplast

Answer 16

cyanobacteria

Question 17

lytic cycle

Answer 17

virus introduces its genome into host cell by hijacking its machinery to make new copies and released through lysis

Question 18

lysogenic cycle

Answer 18

viral DNA gets inserted into host cells DNA, and replicates and cell divides causing no harm to cell

Question 19

describe common steps of viral attack

Answer 19

1. attachment with specific host receptor
2. penetration (uncoat of nucleocapsid)
3. protein synthesis of viral proteins
4. replication
5. assembly of viral progeny
6. release

Question 20

where does bacteriophage assembly occur

Answer 20

cytoplasm

Question 21

how are non enveloped viruses released from host cell

Answer 21

by lysis of cell (attack peptidoglycan or membrane)

Question 22

how are enveloped viruses released from host cell

Answer 22

budding - viral proteins placed into hosts membrane then deform membrane and pinch off via membrane fusion

Question 23

how are pox viruses released from host cell

Answer 23

use host actin tails to propel through host membrane

Question 24

tropism

Answer 24

will bind to specific tissue receptors

Question 25

viruses

Answer 25

protein and nucleic acid (DNA/RNA), only replicate in host cells, nucleocapsid, 10-400nm