DNA Repair and Viruses

Flashcards of key vocabulary terms about DNA repair, viruses and bacteriophages.

Glycosylase

Enzyme that removes oxidized nucleobases, initiating DNA repair.

Photoreactivation

Repair mechanism using light energy to break covalent bonds of thymine dimers.

Excision Repair

Repair mechanism involving enzyme removal of damage, followed by DNA polymerase and ligase repair.

SOS Repair

Last-ditch repair mechanism in prokaryotes induced by extensive DNA damage.

Special DNA Polymerase

Enzyme in SOS repair that synthesizes DNA even in extensively damaged regions.

Xeroderma pigmentosum (XP)

Disease characterized by susceptibility to UV-induced skin cancer due to defects in nucleotide excision repair.

BRCA1 and BRCA2

Genes associated with human breast cancer involved in double-stranded DNA break repair.

Viruses

Contain genetic information (DNA or RNA) within a protective coat.

Viruses

Infectious agents that are not organisms and lack their own metabolism, replication, or motility.

Bacteriophages (Phages)

Viruses that infect prokaryotes.

Virion

Infectious virus particle containing nucleic acid inside a protein coat and optionally a membrane.

Capsid

Protein coat that protects nucleic acids in a virus.

Capsomeres

Identical subunits composing the capsid.

Nucleocapsid

Capsid plus nucleic acids.

Enveloped Viruses

Viruses with a lipid bilayer envelope.

Non-enveloped (Naked) Viruses

Viruses lacking an envelope; more resistant to disinfectants.

-viridae

Viral classification suffix for families.

-virus

Viral classification suffix for genus.

Lytic Life Cycle

Life cycle where the virus replicates and lyses the host cell

Lysogenic Life Cycle

Life cycle where viral DNA integrates into the host genome.

Lytic Phage

Phage that always has a lytic life cycle.

Temperate Phage

Phage with both lytic and lysogenic life cycles.

Lysogen

Infected cell in the lysogenic life cycle.

Prophage

Integrated viral DNA in the host genome.

Lysogenic Conversion

Change in phenotype of a lysogen caused by the prophage.

Plaques

Zones of clearing from bacterial lysis in a plaque assay.

Titer

Concentration of phage in the original sample.

Restriction Enzymes

Enzymes that recognize and cut specific DNA sequences.

Modification Enzymes

Enzymes that methylate host sequences at the restriction site, protecting them from restriction enzymes.

CRISPR System

System where phage spacer DNA is inserted into bacterial DNA to provide a record of infection.