MODULE 5

Question 1

TF Bacteria and archaea have ribsosomal binding sites

Answer 1

F

Question 2

what is folding in translation dictated by

Answer 2

○ pH
○ Metals
○ AA property and position
○ Conformational entropy (spontaneous)
○ Chaperones guide process

Question 3

what is a virus

Answer 3

• Genetic element encapsulated in a protein shell (capsid)

Question 4

TF a virus can be either DNA or RNA never both

Answer 4

T

Question 5

what is segmented vs non segmented DNA

Answer 5

○ Segmented = multiple fragments
○ Non segmented = 1 strand

Question 6

what are 2 type of virus (membrane related)

Answer 6

naked vs encapsulated

Question 7

what is an extracellular virus called

Answer 7

a virion

Question 8

TF Viruses are very small and can usually only be seen with electron microscopy

Answer 8

T

Question 9

how many base pair and proteins do viruses usually have

Answer 9

• Around 1000 base pairs
• Around 7-1000 proteins

Question 10

what is the structure of a capsid

Answer 10

○ made of protein subunits called capsomeres
○ 1 or more diff protein
○ Self assembly or requires a host

Question 11

what are the 2 primary shapes of a virion

Answer 11

rods- helical symmetry
spherical - icosahedral symmetry

Question 12

why is spherical - icosahedral symmetry the best arranegement

Answer 12

• Simplest and most effective
• Fewest capsomeres needed
• Req less energy but more proteins
• has 20 triangular faces and 12 corners

Question 13

what is the complex shape of a virion

Answer 13

Icosahedral heal + helical tail
- head (capsid) holds the viral genome
- tail contains sheath and tail fibers

Question 14

what are the tail fibers made of on a virion

Answer 14

peptidoglycan-like polymer on amoeba viruses

Question 15

what does the naked virus vs the enveloped virus have

Answer 15

• Naked virus: capsid + nucleic acid
• Enveloped virus: membrane + capsid
  + nucleic acid

Question 16

what is the spike protein and what does it do

Answer 16

Protein at the surface of viruses
- Attach and enter host cells
- Detach from host cell surface

Question 17

what are 3 different viruses and what enzymesdo they carry

Answer 17

• Bacteriophage – lysozyme-like enzyme
• RNA viruses – RNA replicase
• Retroviruses (special) – Reverse transcriptase

Question 18

if a virus has lipids what can you deduce about it

Answer 18

Its classified as an enveloped virus
○ Bc it most likely has a lipid membrane

Question 19

what are the categories we classify viruses by

Answer 19

• nucleic acid type (DNA,RNA,segmented or not)
• Naked or enveloped
• Morphology
• Baltimore Classification

Question 20

what is BC1

Answer 20

double stranded DNA

Question 21

what is the BC2

Answer 21

single stranded DNA

Question 22

what is BC3

Answer 22

double stranded RNA

Question 23

what is BC4

Answer 23

+ve sense RNA

Question 24

what is BC5

Answer 24

-ve sense RNA

Question 25

what is BC6

Answer 25

reverse transcribing RNA

Question 26

what is BC7

Answer 26

reverse transcribing double stranded DNA

Question 27

viruses infecting their host depends on

Answer 27

the host Baltimore Classification Naked or enveloped

Question 28

what are the steps to phages infecting bacteria (5)

Answer 28

attachment to the cell penetration of DNA biosynthesis(DNA replicates) Maturation of bacteriophages Lysis of new cells

Question 29

whats the virion growth curve steps

Answer 29

-Innoculation (virus binds cells) - Eclipse: virions penetrate cells - Burst: viral particles released - burst size: # virions released

Question 30

how do temperate phages infect bacteria

Answer 30

- phage infects a cell - phage DNA incorporates into host genome - cell divides, DNA passes to daughters - prophage DNA excised and enters lytic lifecycle bc of stressful conditions - phage proteins made - particles assemble + lysis

Question 31

what is a lysogen

Answer 31

a bacterium that has a “resident” phage integrated in the bacterial genome or as a plasmid

Question 32

what is Lysogenic or phage conversion

Answer 32

the “resident” phage changes the phenotype of the lysogen

Question 33

how does viral infection work in eukaryotes

Answer 33

- attaches to a cell (attachment) - cell engulfs virus(penetration) - viral contents released in cell(uncoating) - viral RNA enters nucleus and is replicated(biosynthesis) - new phages assemble(assembly) - viral particles released, cell continues to make more(release)

Question 34

what the difference in release in naked vs enveloped viruses

Answer 34

naked = lysis due to accumulation, host doesnt survive enveloped = buds” out through host membrane, host cell can survive, continued slow release

Question 35

what do phages attack on the surfaces

Answer 35

capsules and slime layer flagellum CW LPS

Question 36

TF a universal phage exists

Answer 36

F

Question 37

what are the outcomes of a persistent viral infection

Answer 37

- Latent: virus is dormant and reactivates § Infected for life in nervous system, reactivates and goes dormant - Chronic: never eliminated, always production, never

Question 38

what is the outcome of viral infection of cancer

Answer 38

Modification and overproduction of cells from viruses can cause cancer

Question 39

how can eukaryotes be chronically infected by viruses

Answer 39

everse transcribed ○ RNA --> DNA ○ Then inserted into ur genome Genetically modified to produce the virus

Question 40

explain why a lytic and a lysogenic (temperate) bacteriophage would not yield the same number of plaque forming units (PFUs) despite infecting the cells with the same number of infectious viral particle

Answer 40

Plaques are formed during lysis and lysogenic infection don’t always result in lysis

Question 41

how do we quantify the virus

Answer 41

in PFUs

Question 41

whats needed in order to grow viruses

Answer 41

- Needs living host cells - Needs the host cell type to support viral infection

Question 42

in baltimore classification, what are the +ve and -ve DNA sequences +ve and -ve RNA sequences for

Answer 42

+ve strand DNA sequence = mRNA sequence (template for translation) -ve strand DNA sequence = use as a template for mRNA sequence +ve strand RNA = used as a template for translation -ve strand RNA = cannot be used as a template for translation

Question 43

TF To create mRNA, you need a negative strand DNA

Answer 43

T

Question 44

TF To create a protein, you need a positive strand RNA

Answer 44

T