Molecular Genetics and DNA Replication Practice Flashcards

Vocabulary practice flashcards covering eukaryotic replication, transcription mechanisms, splicing, and the components of the replication fork as detailed in the lecture transcript.

DNA polymerase

An enzyme that catalyzes the formation of phosphodiester bonds between the $3'$ hydroxyl($-OH$) of one nucleotide and the $5'$ phosphate($PO_3^{-4}$) of an adjacent nucleotide.

RNA pol ll

The enzyme in eukaryotes responsible for transcribing protein coding genes.

AT-rich DNA sequence

A type of sequence that would require the least energy to denature (separate) complementary DNA strands, all other things being equal.

DNA nucleotide characteristics

Distinct components that do not include a $-CH_3$ on the $3'C$ of the sugar.

Avery, MacLeod, and McCarty experiment

An experiment with Streptococcus pneumoniae where treating heat killed S strain remnants with DNase prevented infection in mice, identifying DNA as the transforming principle.

Histone proteins

Proteins in eukaryotes around which DNA is wrapped to organize into nucleosomes.

Nucleosomes

The structure formed when eukaryotic DNA is wrapped around histone proteins.

Primer

A short ($12 ext{-}24 ext{ bsp}$) single stranded RNA/DNA molecule complementary and antiparallel to template DNA that serves as a starting point for daughter strand synthesis.

Semiconservative

The observed mode of DNA replication where each daughter duplex contains one original parental strand and one newly synthesized strand.

SAR gas rule

A principle where a vertebrate genome containing $27\%$ cytosine (C) should also be composed of approximately $27\%$ guanine (G).

Rho-independent (intrinsic) termination

An mRNA termination mechanism involving an inverted repeat in the DNA sequence that results in a stem Loop hair pinstructure in the bacterial mRNA.

Mitochondria

Organelles descended from an endosymbiotic prokaryote ancestor.

Heterochromatin

Regions of eukaryotic chromosomes that are more condensed during interphase and contain few express genes.

Exons

Segments of pre-mRNA that remain as part of the mature mRNA after processing.

Introns

Non-coding segments of pre-mRNA that are removed during post transcriptional mRNA processing.

Okazaki fragments

Short segments of DNA used during replication in the opposite direction of the replication fork progression.

Molecular genetics

A subdiscipline of genetics focusing on how genetic information is encoded, replicated, and expressed.

General transcription factors

Proteins in eukaryotes that aid RNA polymerase in recognizing and binding to promoters.

Transcription

The process in which a DNA template is used to synthesize an RNA molecule.

Codon

Three consecutive nucleotides on an mRNA strand that specify a particular amino acid.

TATA box

A sequence commonly found in the core promoter of a eukaryotic Gene.

mRNA splicing sequence

The process where the $5'$ splice site is cut, the $5'G$ binds to a branch point A, the $3'$ splice site is cut, and then exons are joined.

small nuclear ribonucleic particles (snRNPs)

Components that make up the spliceosome of eukaryotes and are involved with mRNA splicing.

C value paradox

The observation that genome size is unrelated to biological complexity (number of genes) across species and high-level taxa.

Telomeres

Terminal regions of chromosomes that often contain important genes, though this statement is noted as incorrect in the text.

Dnab (helicase)

The protein that separates DNA strands and unwinds the helix.

DNA ligase

The enzyme that joins DNA segments on lagging strands.

DNA gyrase (topoisomerase)

The enzyme that relieves coiling stress ahead of the replication fork.

Primase

The enzyme that synthesizes RNA primers.

DNA polymerase lll

The enzyme that synthesizes leading and lagging DNA strands.

DNA polymerasel

The enzyme that removes and replaces RNA primers with DNA.

Beta sliding clamp

A component that anchors DNA polymerase to DNA template strands.

Single-stranded binding protein

A protein that prevents separated DNA strands from renaling.

Cis regulatory elements

DNA sequences located in the proximal promoter or farther way recognized by regulatory transcription factors to affect transcription rate.

Alternative splicing

A mechanism by which the same gene produces different polypeptides in different cell types, explaining the disparity between gene count and polypeptide variety.