DNA replication and repair

building blocks of RNA and DNA

what are nucleotides

A=T, C=G

chargaff's rule

gouty arthritis

what is the result of excess purines

megaloblastic anemia

what is the result of defects in pyrimidine synthesis

red sores on tongue

what is the oral manifestation of megaloblastic anemia

chromatin

Clusters of DNA, RNA, and proteins in the nucleus of a cell

nucleosomes

DNA coiled around histones

euchromatin

The less condensed form of eukaryotic chromatin that is available for transcription.

heterochromatin

Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed.

helicase

An enzyme that untwists the double helix of DNA at the replication forks.

DNA primase

synthesizes a short RNA primer to provide a 3'-OH group for the attachment of DNA nucleotides

topoisomerase

corrects "overwinding"/ supercoiling ahead of replication forks by breaking, swiveling, and rejoining DNA strands

DNA polymerase III

synthesizes new DNA only in the 5' to 3' direction

mismatch repair

The cellular process that uses special enzymes to fix incorrectly paired nucleotides.

DNA ligase

Connects okazaki fragments

DNA polymerase I

removes the RNA primer and replaces it with DNA

Pritelivir

viral helicase inhibitor effective against Herpes simplex virus

blocks ligation and leads to cell death

what does topoisomerase inhibitor do?

Quinolones

topoisomerase inhibitor used for treatment of skin and tissue infections, chronic bronchitis, community-acquired and nosocomial pneumonia, and UTI

Anti-cancer drugs

other use for topoisomerase inhibitor?

acyclovir

DNA polymerase inhibitor effective against herpes simplex virus and shinglees

Telomeres

Repeated DNA sequences at the ends of eukaryotic chromosomes.

telomerase

An enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells.

DNA damage response

what is the result of short telomeres

cellular senescence, tumor suppreessor mechanism, and apoptosis

what is a DNA damage response

Dyskeratosis Congenita

genetic disease causing accelerated shortening of telomeres. may result from lowered telomerase activity

direct reversal

alkylation damage reversed when alkyl group transferred

base excision repair and nucleotide excision repair

DNA damage cleaved by endo/exonuclease and correct base inserted

Non-homologous end joining

A mechanism for repairing double-strand breaks in DNA that involves quickly bringing together, trimming, and rejoining the two broken ends; results in a loss of information at the site of repair.

lynch syndrome

defects in mismatch repair, leads to high risk of colon cancer and endometrial cancer

Xereoderma Pigmentosum

hypersensitivity to UV caused by defective nucleotide excision repair

Induce mRNA degradation and translational repression

role of miRNA

remove negative regulation by miRNA

role of lncRNA

alternative splicing

Splicing of introns in a pre-mRNA that occurs in different ways, variations allow one gene to code for many different proteins