chapter seven: dna completion

DNA Nucleotide Composition

A monomer consisting of one phosphate group, one 5-carbon deoxyribose sugar, and one nitrogenous base.

Antiparallel Strands

The orientation where two DNA strands run in opposite directions, with one strand running 5' to 3' and the other 3' to 5'.

Complementary Base Pairing (DNA)

Adenine (A) pairs with Thymine (T), and Cytosine (C) pairs with Guanine (G) via hydrogen bonds.

DNA vs. RNA Sugar

DNA contains deoxyribose sugar, whereas RNA contains ribose sugar.

DNA vs. RNA Bases

DNA uses Adenine, Thymine, Cytosine, and Guanine, while RNA uses Adenine, Uracil, Cytosine, and Guanine.

Central Dogma

The principle stating genetic information flows from DNA to RNA via transcription, and RNA to protein via translation.

Transcription

The process of synthesizing an RNA molecule from a DNA template inside the nucleus.

RNA Polymerase

An enzyme that binds to a promoter, unwinds DNA, and synthesizes a complementary RNA strand.

Promoter

A specific DNA sequence at the beginning of a gene where RNA polymerase attaches to start transcription.

Terminator

A DNA sequence marking the end of a gene that signals RNA polymerase to stop and detach.

5' Cap and 3' Poly-A Tail

Protective modifications added to mRNA ends in the nucleus to prevent degradation.

Introns

Non-coding regions of a gene that are spliced out of mRNA during nuclear processing.

Exons

Coding regions of mRNA that remain after splicing and code for amino acids.

Messenger RNA (mRNA)

The RNA strand that carries genetic code from DNA in the nucleus to ribosomes in the cytoplasm.

Ribosomal RNA (rRNA)

The structural RNA component that combines with proteins to form ribosomes.

Transfer RNA (tRNA)

Adaptor molecules that carry specific amino acids to the ribosome by pairing their anticodons with mRNA codons.

Codon

A three-nucleotide sequence on mRNA that specifies a single amino acid.

Anticodon

A three-nucleotide sequence on tRNA complementary to a specific mRNA codon.

Translation Initiation

Assembles the small ribosomal subunit, mRNA, initiator tRNA (carrying Met), and large subunit at the START codon.

Translation Termination

Reaches a stop codon where a release factor protein binds, causing the finished polypeptide chain to detach.