DNA TRANSCRIPTION AND TRANSLATION

DNA structure

The arrangement and organization of DNA, including its double helix configuration and components.

Nucleotide

The basic building block of DNA and RNA, consisting of a five-carbon sugar, a phosphate group, and a nitrogenous base.

Antiparallel

Describes the orientation of the two strands of DNA, where one runs 5' to 3' and the other runs 3' to 5'.

Helicase

An enzyme that unwinds the DNA double helix by breaking hydrogen bonds between base pairs.

Okazaki fragments

Short segments of DNA synthesized on the lagging strand during DNA replication.

Leading strand

The DNA strand that is synthesized continuously in the same direction as the replication fork.

Phosphodiester bond

The bond that links the sugar and phosphate groups in the DNA backbone.

RNA polymerase

The enzyme responsible for synthesizing mRNA from a DNA template during transcription.

Template strand

The strand of DNA that is read by RNA polymerase to synthesize a complementary mRNA strand.

5' cap

A modified guanine nucleotide added to the 5' end of pre-mRNA during RNA processing.

Poly-A tail

A sequence of adenine nucleotides added to the 3' end of mRNA to protect it from degradation.

Amino acid

The building blocks of proteins, linked together by peptide bonds during translation.

Stop codon

A nucleotide triplet within mRNA that signals the end of translation.

Peptide bond

The chemical bond formed between two amino acids during protein synthesis.

Point mutation

A genetic mutation where a single nucleotide is altered.

Frameshift mutation

A genetic mutation caused by insertion or deletion of nucleotides that alters the reading frame.

Silent mutation

A mutation that changes a codon but does not change the corresponding amino acid.

Nonsense mutation

A mutation that changes a normal codon into a stop codon, leading to premature termination.

mRNA

Messenger RNA, which carries genetic information from DNA to the ribosome.

Codon

A sequence of three nucleotides in mRNA that corresponds to a specific amino acid.

Promoter region

The region of DNA where RNA polymerase binds to initiate transcription.

Terminator

The DNA sequence that signals the end of transcription.

Introns

Non-coding sequences of pre-mRNA that are removed during RNA processing.

Exons

Coding sequences of pre-mRNA that are retained during RNA processing.

Mutagen

An agent that causes changes in the DNA sequence, potentially leading to mutations.

Chargaff's rules

The observation that DNA from any cell of any organism has a 1:1 ratio of pyrimidine and purine bases.

Ribosome

The cellular machinery that facilitates translation of mRNA into proteins.