CHEM 3410 Flashcards

Flashcards for CHEM 3410 exam review, covering DNA Replication, RNA Transcription, and Protein Translation.

What is the function of DNA gyrase?

Unwinds supercoils during DNA replication.

What is the role of Helicase in DNA replication?

Melts/unwinds the DNA double helix during replication.

What is the function of SSB (single-strand binding proteins)?

Prevent reannealing of single-stranded DNA during replication.

What is the role of Primase in DNA replication?

Synthesizes short RNA primers during DNA replication.

What is the primary function of DNA polymerase III?

Bulk DNA synthesis; elongates the DNA strand in the 5' to 3' direction.

What is the function of DNA Polymerase I?

Removes RNA primers and fills the resulting gaps during DNA replication.

What is the function of Ligase?

Joins Okazaki fragments on the lagging strand during DNA replication.

What is the function of Telomerase?

Extends chromosome ends/telomeres.

What is the function of Gamma (γ) polymerase?

Mitochondrial DNA replication

What is the leading strand?

Continuous 5'→3' synthesis alongside the replication fork.

What is the lagging strand?

Discontinuous synthesis of Okazaki fragments, requiring repeated priming.

What is the repeated sequence added to telomeres by telomerase to prevent end shortening?

TTAGGG

What does RNA Polymerase I synthesize?

rRNA synthesis

What does RNA Polymerase II synthesize?

mRNA and many non-coding RNAs synthesis

What does RNA Polymerase III synthesize?

tRNA and small RNAs synthesis

Where is the TATA box located and what does it control?

-30 to -25; selective expression

What is the sequence of the GC box, and what type of genes does it regulate?

GGGCGG; housekeeping genes

Where are enhancers/silencers located and what binds to them?

Distant, bound by activators/repressors

What is the template (antisense) strand?

Used by RNA polymerase to synthesize RNA.

What is the coding (sense) strand?

Identical to RNA sequence (except T→U).

What happens in ρ-dependent termination?

Rho factor helicase releases the RNA–DNA hybrid.

What happens in intrinsic termination?

GC-rich hairpin & poly‑U cause polymerase pausing and release.

What is the function of 5' capping (7-methylguanosine)?

Protects mRNA and aids ribosome binding.

What is the function of 3' polyadenylation (poly‑A tail)?

Increases mRNA stability.

What happens during splicing?

Removal of introns; exons ligated (alternative splicing → isoforms).

What is RNA editing?

A→I or C→U deamination alters coding potential

What is the spliceosome?

Complex mediating intron removal.

What is homologous recombination?

Complex facilitating exchange bewtween similar sequences during meiosis.

What is non-homologous recombination?

End-joining between dissimilar sequences; transposons/viral integration.

What is the Shine–Dalgarno sequence?

Ribosome-binding site upstream of AUG.

What is the function of AUG?

Start codon

What is the function of Stop Codon?

signals translation termination

What is the difference between the Sense and antisense strand?

coding vs. template in transcription

What is the wobble position?

3′ anticodon flexibility enabling degeneracy