Block II - Microbial Genetics and Virology I/II

Question 1

Nucleotides

Answer 1

composed of nitrogenous base, a 5-carbon sugar (can be ribose [RNA] or deoxyribose [DNA]), and up to 3-phosphate groups

Question 2

Purines

Answer 2

Six carbon rings - Adenine (A) and Guanine (G)

Question 3

Pyrimidines

Answer 3

two joined carbon rings - Cytosine (C) and Thymine (T) OR Uracil (U)

Question 4

How are elements in a nitrogenous ring labelled?

Answer 4

Numerically;

1-6 in pyrimidines
1-9 in purines

Question 5

How are elements in sugar labelled?

Answer 5

Numerically with a ` denotation;

3 --> 5

Question 6

Induced mutations

Answer 6

Mutations that are brought about by mutagens

Question 7

Spontaneous mutations

Answer 7

Mutations that occur randomly

Question 8

Silent mutations

Answer 8

Mutations that result in a base change but no change in function (no change in expressed product)

Question 9

Missense mutation

Answer 9

Mutation that results in a change in codons thus a change in product expression

Question 10

Nonsense mutation

Answer 10

Mutation resulting in a premature stop codon

Question 11

Frameshift mutation

Answer 11

insertion/deletion of a BP other than a multiple of three (so 1 or 2 BPs)

Question 12

Transformation

Answer 12

Acquisition of new genetic markers by incorporation of added DNA

Question 13

What are the layers of a virus?

Answer 13

Capsid (surrounds the DNA/RNA), +/- envelope which will contain protein molecule (spikes)

Question 14

What is a capsid?

Answer 14

a protein shelf that encloses the DNA/RNA in a virus

Question 15

What is the term given to a capsid + viral genome?

Answer 15

Nucleocapsid

Question 16

Stage 1 of the replication cycle

Answer 16

Attachment: Virus attaches to host cell

Question 17

Stage 2 of the replication cycle

Answer 17

Penetration & Uncoating: virus penetrates the host membrane and injects nucleic acid into the cell

Question 18

Stage 3 of the replication cycle

Answer 18

Synthesis of viral genome: virus nucleic acid replicates using host machinery

Question 19

Stage 4 of the replication cycle

Answer 19

Assembly, Maturation, and release: new viral genome is packaged into viral particles and released from the cell; host cell MAY be destroyed in process

Question 20

What are some impacts of virus replication?

Answer 20

Cell lysis, alteration of cell membrane, apoptosis

May also be inapparent resulting in latent, persistent, chronic infections