DNA Replication & Protein Synthesis - Vocabulary Flashcards

Vocabulary flashcards covering key terms and definitions from DNA replication and protein synthesis topics from the lecture notes.

Central Dogma

Flow of genetic information: DNA is replicated, then transcribed to RNA, which is translated into protein.

DNA Replication

Process of copying the DNA before cell division, occurring in the nucleus during interphase.

Semiconservative Replication

Each daughter DNA molecule consists of one old (parent) strand and one new strand.

Origin of Replication (ORI)

Site where DNA replication begins; single ORI in prokaryotes, multiple ORIs in eukaryotes.

Helicase

Enzyme that unwinds the DNA double helix by breaking hydrogen bonds.

Single-Strand Binding Proteins (SSB)0definition2

Stabilize unwound DNA to keep strands apart during replication.

DNA Polymerase

Enzyme that adds nucleotides to form a new DNA strand and proofreads for errors.

DNA Primase

Synthesizes RNA primers to provide a starting point for DNA synthesis.

DNA Ligase

Enzyme that joins Okazaki fragments on the lagging strand by forming phosphodiester bonds.

Okazaki Fragment

Short DNA sequences synthesized on the lagging strand in fragments.

Leading Strand

DNA strand synthesized continuously toward the replication fork (5' to 3').

Lagging Strand

DNA strand synthesized discontinuously as Okazaki fragments away from the replication fork.

Replication Fork

Y-shaped region where the parental DNA strands unwind and replication occurs.

Antiparallel

Two DNA strands run in opposite 5' to 3' directions.

Nucleotide

Monomer units of DNA/RNA: sugar, phosphate, and base.

Base Pairing (DNA)

A pairs with T; C pairs with G.

RNA Base Pairing

A pairs with U; C pairs with G in RNA.

Transcription

Process of copying a DNA sequence into an RNA molecule in the nucleus.

mRNA (Messenger RNA)

RNA that carries genetic information from DNA to the ribosome for protein synthesis.

Promoter

DNA sequence where RNA polymerase binds to initiate transcription.

TATA Box

Promoter element in many eukaryotes essential for transcription initiation.

Transcription Factors

Proteins that help RNA polymerase bind to promoter in eukaryotes.

RNA Polymerase

Enzyme that synthesizes RNA from a DNA template during transcription.

Initiation (Transcription)

RNA polymerase binds promoter and unwinds DNA to start RNA synthesis.

Elongation (Transcription)

RNA polymerase adds RNA nucleotides in the 5' to 3' direction as it moves along DNA.

Termination (Transcription)

Terminator sequences signal the end of transcription and RNA is released.

RNA Processing

Modifications in eukaryotes: intron splicing, 5' cap addition, and 3' poly-A tail addition.

Spliceosome

RNA–protein complex that removes introns from pre-mRNA.

Intron

Non-coding regions of RNA that are removed during splicing.

Exon

Coding regions of RNA that are retained after splicing.

5' Cap

Modified guanine added to the 5' end of mRNA to facilitate export and translation.

3' Poly-A Tail

Addition of a tail of adenines at the 3' end to protect mRNA and aid export/translation.

Ribosome

Molecular machine that translates mRNA into protein; made of rRNA and proteins.

rRNA

Ribosomal RNA; major component of ribosomes.

tRNA

Transfer RNA; carries amino acids to the ribosome and contains an anticodon.

Codon

Three-nucleotide sequence in mRNA that codes for an amino acid or a stop signal.

Start Codon (AUG)

Codon that begins translation and codes for methionine.

Stop Codons

UAA, UAG, UGA; signal termination of translation.

Genetic Code

Mapping from codons to amino acids; nearly universal and degenerate.

Translation

Process of decoding mRNA into a polypeptide chain at the ribosome.

Ribosome Sites (A, P, E)

A site = incoming tRNA; P site = growing polypeptide; E site = exit of tRNA.

tRNA Anticodon

Three-nucleotide sequence on tRNA that pairs with a codon on mRNA.

Peptide Bond

Bond formed between adjacent amino acids during translation.

Nucleus vs Cytoplasm

Transcription occurs in the nucleus; translation occurs in the cytoplasm.

mRNA Export

Mature mRNA exits the nucleus through nuclear pores to the cytoplasm.

RNA (vs DNA)

RNA is single-stranded, uses ribose and uracil (U); DNA is double-stranded, uses deoxyribose and thymine (T).