BIOC20 LECTURE 4 EXAM QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS LATEST UPDATE

BIOC20 LECTURE 4 EXAM QUESTIONS AND ANSWERS

WITH COMPLETE SOLUTIONS LATEST UPDATE


Viruses

Require host to replicate

Viroids

Small RNA molecules that catalyze replication steps

RNA viruses

Depend on RNA polymerases from host or helper viruses

DNA-based world

Transition from self-replicating RNA molecules to DNA production

Reverse transcriptase

Enzyme that makes DNA copies of RNA

DNA stability

Advantage of DNA over RNA

RNA-dependent RNA polymerases

Enzymes for RNA replication

RNA-dependent DNA polymerases

Enzymes for reverse transcription (RNA to DNA)

DNA-dependent RNA polymerases

Enzymes for transcription (DNA to mRNA)

DNA-dependent DNA polymerases

, Enzymes for DNA replication

Small and medium-sized DNA viruses

Arise as independently replicating genetic elements in cells

Large DNA viruses

Evolve from cellular forms that became intracellular parasites

Viral genes

Encode for structural proteins, DNA replication enzymes, and assembly machinery

Seven Major Virus Groups

Classifications based on genome type and characteristics

Group 1

Viruses with small ssDNA genomes, without envelopes

Group 2

Viruses with widespread dsDNA genomes, can be very large

Group 3

Viruses with + strand RNA genomes, common in plants and vertebrates

Group 4

Viruses with - strand RNA genomes, major infectious diseases in humans

Group 5

Viruses with dsRNA genomes, mostly in fungi

Group 6

Viruses that use reverse transcriptase (DNA or RNA)

Group 7

Satellite viruses, nucleic acids, and viroids with small genomes