FINAL EXAM P1

Question 1

virology

Answer 1

not free-living, must be produced inside the host (intracellular)
not cellular
small genome between 4 - 400

Question 2

Baltimore classification scheme

Answer 2

based on the nucleic acid content and metabolism of the virus

Question 3

bacteriophage

Answer 3

viruses that infect bacteria

Question 4

capsid (capsomere proteins)

Answer 4

a protein coat/capsule that protects the genome of the virus
made via capsomeres
recognizes sites for binding to a new host

Question 5

can viruses be seen with a microscope

Answer 5

only with an electron microscope

Question 6

nucleocapsid

Answer 6

a full virus particle

refers to the structure with the nucleic acid and the capsid

Question 7

envelope

Answer 7

the membrane surrounding the nucleocapsid

formed from a small piece of the cytoplasmic membrane of the cell the virus had infected

Question 8

what are the stages of the viral life cycle

Answer 8

attachment, penetration, synthesis, assembly/packaging, and release

Question 9

attachment

Answer 9

aka absorption

the free viral particle attaching to some specific part of the host cell

Question 10

penetration

Answer 10

aka injection
the genomic nucleic acid getting inside of the host cell
in terms of bacteria, the capsid does not enter the host cell, rather the nucleic acid is injected across the cell wall

Question 11

synthesis

Answer 11

the virus starts making the parts needed to assemble more viral particles
needs to synthesize nucleic acid for viral proteins by using cellular machinery and subunits

Question 12

assembly/packaging

Answer 12

putting the nucleic acid inside the capsid

Question 13

release

Answer 13

aka lysis in case of bacteria

breaks open and releases particles

Question 14

how is a phage/virus detected

Answer 14

by its ability to infect and kill the bacteria

Question 15

what is a plaque assay

Answer 15

used for bacteriophage

a plate has host cells forming a lawn. if a bacteriophage is infecting them, plaque will form

Question 16

what are plaque

Answer 16

clear spots on a bacterial lawn indicating a phage is present
used to quantify data and isolate pure viral strains

Question 17

how are viruses classified

Answer 17

based on what type of nucleic acid they carry inside and how they replicate it once inside the host cell

Question 18

double stranded viral DNA

Answer 18

DNA replication works the same way as it does in cells, known as classical semiconservative replication
RNAP makes mRNA to make proteins
dsDNA is fairly simple for viruses

Question 19

single stranded viral DNA

Answer 19

has an extra step

transcription can only be done with the double strand, so the single strand has to be converted to a double

Question 20

how is ssDNA converted to dsDNA

Answer 20

first step is to synthesize the complementary strand
the plus strand is already present, so we need the minus strand, simply DNA synthesis
to get back to the ssDNA, the minus strand is a template to make copies of the plus strand

Question 21

+RNA

Answer 21

same sequence as mRNA
usually ssRNA, as soon as it enters the cell it can start making viral proteins (when used as mRNA)
makes -RNA

Question 22

-RNA

Answer 22

same is the same as the complementary strand
can’t be used as mRNA
must first use RNA replicase to make a plus strand (mRNA), which is then used to make viable proteins and as a template for more -RNA
makes +RNA

Question 23

RNA replicase

Answer 23

needed to take RNA and make an RNA copy

one of the first proteins made by mRNA

Question 24

ssRNA retrovirus

Answer 24

has single stranded +RNA genomes

when entering the host, they’ve brought their own enzyme called reverse transcriptase

Question 25

reverse transcriptase

Answer 25

takes an RNA template and makes a DNA copy

this is the only organism on Earth that does the opposite, using RNA as a template for DNA

Question 26

transcription

Answer 26

the process of taking DNA and making RNA copies