Lesson 2: Transcription and Translation

Vocabulary flashcards covering key terms and definitions from the lecture on transcription, translation, and DNA–RNA relationships.

DNA (Deoxyribonucleic Acid)

The double-stranded genetic molecule that stores hereditary information in the nucleus; composed of the bases A, T, C, and G.

RNA (Ribonucleic Acid)

A single-stranded nucleic acid transcribed from DNA; contains the bases A, U, C, and G and carries instructions for protein synthesis.

Chromatin

Relaxed, thread-like form of DNA wrapped around histone proteins that fills the nucleus when the cell is not dividing.

Chromosome

Highly coiled, X-shaped structure of DNA and proteins visible during cell division that ensures orderly DNA segregation.

Histone

Structural protein ‘spool’ around which DNA winds, helping package the genome tightly inside the nucleus.

Nucleus

The cell’s ‘headquarters’ housing most genetic material and the site of transcription.

Transcription

Nuclear process in which a gene’s DNA sequence is copied into messenger RNA (mRNA) by RNA polymerase.

Translation

Cytoplasmic process at the ribosome where mRNA codons are read to assemble amino acids into a protein.

RNA Polymerase

The enzyme that unwinds DNA and synthesizes complementary mRNA during transcription.

Ribosome

Cytoplasmic organelle (often bound to rough ER) that reads mRNA codons and links amino acids together.

mRNA (Messenger RNA)

RNA transcript that carries the coded genetic message from the nucleus to the ribosome for translation.

Codon

A sequence of three RNA bases that specifies a particular amino acid or a start/stop signal during translation.

Amino Acid

The building block of proteins; linked together in a specific order dictated by mRNA codons.

Gene

A segment of DNA that contains the coding information for producing a specific protein or RNA molecule.

Exon

Coding region of a gene that remains in mRNA after transcription and RNA processing.

Intron

Non-coding sequence within a gene that is removed from the RNA transcript before translation.

Promoter

DNA sequence upstream of a gene that signals RNA polymerase where to begin transcription.

Terminator

DNA sequence that signals RNA polymerase to stop transcription and release the mRNA strand.

Mitosis

Somatic cell division requiring complete DNA replication so each daughter cell receives identical chromosomes.

Protein Synthesis

Two-stage cellular process (transcription + translation) that builds proteins from genetic instructions.

Central Dogma

Concept describing the one-way flow of genetic information: DNA → RNA → Protein.

Deoxyribose

Five-carbon sugar found in DNA nucleotides that lacks one oxygen atom compared to ribose.

Ribose

Five-carbon sugar present in RNA nucleotides, giving RNA its name.

Stop Codon

mRNA triplet (e.g., UAA, UAG, UGA) that signals the ribosome to end protein synthesis.

Start Codon

mRNA triplet AUG that codes for methionine and initiates translation at the ribosome.

Cytoplasm

Cellular region outside the nucleus where translation occurs and proteins are assembled.

Rough Endoplasmic Reticulum (Rough ER)

Membranous network studded with ribosomes; site of abundant protein synthesis and folding.