Genetics and Cell Biology – Transcription, Translation, Mitosis, and DNA Replication

A comprehensive set of vocabulary flashcards covering transcription, translation, mitosis, DNA structure, replication, and the cell cycle from the lecture notes.

Protein synthesis

The process by which the body builds proteins from amino acids, involving transcription of DNA into RNA and translation of RNA into a polypeptide.

Protein

A chain of amino acids whose sequence determines its structure and function.

Amino acid

The building blocks of proteins; linked together in a specific order to form a protein.

Transcription

The process of converting instructions in DNA into messenger RNA (mRNA) within the nucleus.

Messenger RNA (mRNA)

RNA that carries the genetic information from DNA to the ribosome for protein synthesis; produced in the nucleus and transported to the cytoplasm.

DNA

Double-stranded nucleic acid with a genetic code; forms a double helix with antiparallel strands and base pairing (A–T and C–G). Ends labeled 5' and 3'.

Nucleotide

The basic unit of DNA, consisting of a sugar (deoxyribose), a phosphate group, and a nitrogenous base.

Base triplet

A sequence of three DNA bases that contains information for assembling each amino acid.

Codon

A trio of RNA bases on mRNA that encodes a specific amino acid; uracil replaces thymine in RNA.

RNA polymerase

Enzyme that binds to the DNA template to start transcription and builds the mRNA strand.

Promoter region

DNA sequence where RNA polymerase attaches to initiate transcription.

Transcription terminator

DNA sequence that signals the end of transcription; leads to dissociation of RNA polymerase.

Hairpin loop

A structural feature in mRNA that can cause RNA polymerase to dissociate at the transcription terminator.

Intron

Noncoding sequences in RNA that are removed before translation.

Exon

Coding sequences that are spliced together to form functional mRNA.

Ribosome

Molecular machine that reads mRNA and synthesizes proteins by linking amino acids.

Start codon

The codon (often AUG) that signals the beginning of translation.

Stop codon

Codon that signals termination of translation.

tRNA

Transfer RNA; carries specific amino acids to the ribosome and has an anticodon that pairs with the mRNA codon.

Anticodon

A sequence on tRNA complementary to the mRNA codon, enabling correct amino acid incorporation.

Initiation complex

Complex formed by the small ribosomal subunit, first tRNA, and mRNA; the large ribosomal subunit then joins.

A site

Acceptor site on the ribosome where the next tRNA binds and amino acids are added to the growing chain.

P site

Peptidyl site on the ribosome where the growing polypeptide chain is held.

Translation elongation

Process of adding amino acids to the growing polypeptide chain as the ribosome moves along the mRNA.

Polypeptide

A chain of amino acids that folds into a protein.

Mitosis

Cell division that results in two genetically identical daughter cells; consists of prophase, metaphase, anaphase, and telophase.

Diploid

Cells containing two sets of chromosomes (23 pairs in humans), one maternal and one paternal per pair.

Chromatid

One of two identical copies of a duplicated chromosome held together before a cell divides.

Sister chromatid

Two identical copies of a chromosome connected at the centromere that separate during mitosis.

Chromosome

A structure of DNA and proteins; during replication consists of two sister chromatids.

Centriole

Structure from which spindle fibers originate during mitosis.

Spindle fibers

Microtubules that separate chromosomes during mitosis.

Nuclear envelope

Membrane surrounding the nucleus that breaks down in prophase and reforms in telophase.

Prophase

First stage of mitosis; chromosomes condense, nuclear envelope dissolves, and spindle forms.

Metaphase

Stage where chromosomes align along the cell equator with spindle attachment.

Anaphase

Stage where sister chromatids separate and move to opposite poles.

Telophase

Stage where nuclear envelopes reform around chromosomes and the chromosomes de-condense.

Cytokinesis

Division of the cytoplasm, resulting in two distinct daughter cells.

Interphase

Phase of the cell cycle when the cell grows and carries out metabolic activities; includes G1, S, and G2 phases.

G1

First growth phase; cell growth and normal function occur.

S phase

DNA replication phase, producing two copies of each chromosome.

G2

Second growth phase; cell prepares for mitosis.

5' to 3' direction

Direction of synthesis for nucleic acids; new nucleotides are added to the 3' end.

Semiconservative replication

DNA replication model in which each new DNA molecule contains one original strand and one new strand.

Replication fork

Region where DNA strands separate to allow replication to occur.

Complementary base pairing

A pairs with T (DNA) and C pairs with G; in RNA, A pairs with U; ensures accurate copying of genetic information; A–T have two H-bonds, G–C have three.

Uracil

RNA base that replaces thymine during transcription/translation.