Block II - Microbial Genetics and Virology I/II Flashcards
Nucleotides
composed of nitrogenous base, a 5-carbon sugar (can be ribose [RNA] or deoxyribose [DNA]), and up to 3-phosphate groups
Purines
Six carbon rings - Adenine (A) and Guanine (G)
Pyrimidines
two joined carbon rings - Cytosine (C) and Thymine (T) OR Uracil (U)
How are elements in a nitrogenous ring labelled?
Numerically;
1-6 in pyrimidines
1-9 in purines
How are elements in sugar labelled?
Numerically with a ` denotation;
3 --> 5
Induced mutations
Mutations that are brought about by mutagens
Spontaneous mutations
Mutations that occur randomly
Silent mutations
Mutations that result in a base change but no change in function (no change in expressed product)
Missense mutation
Mutation that results in a change in codons thus a change in product expression
Nonsense mutation
Mutation resulting in a premature stop codon
Frameshift mutation
insertion/deletion of a BP other than a multiple of three (so 1 or 2 BPs)
Transformation
Acquisition of new genetic markers by incorporation of added DNA
What are the layers of a virus?
Capsid (surrounds the DNA/RNA), +/- envelope which will contain protein molecule (spikes)
What is a capsid?
a protein shelf that encloses the DNA/RNA in a virus
What is the term given to a capsid + viral genome?
Nucleocapsid
Stage 1 of the replication cycle
Attachment: Virus attaches to host cell
Stage 2 of the replication cycle
Penetration & Uncoating: virus penetrates the host membrane and injects nucleic acid into the cell
Stage 3 of the replication cycle
Synthesis of viral genome: virus nucleic acid replicates using host machinery
Stage 4 of the replication cycle
Assembly, Maturation, and release: new viral genome is packaged into viral particles and released from the cell; host cell MAY be destroyed in process
What are some impacts of virus replication?
Cell lysis, alteration of cell membrane, apoptosis
May also be inapparent resulting in latent, persistent, chronic infections
