Biology Chapter 11 - DNA & Genes

Nitrogen Base: Comprises a carbon ring structure containing nitrogen; four types in DNA: adenine (A), guanine (G), cytosine (C), thymine (T).
Double Helix: The characteristic structure of DNA formed by two intertwined strands.
DNA Replication: The cellular mechanism responsible for copying DNA contained in chromosomes.

Messenger RNA (mRNA): Transfers genetic information from DNA in the nucleus to the cytoplasm for protein synthesis.
Ribosomal RNA (rRNA): Main component of ribosomes; binds to mRNA to facilitate assembly of amino acids into proteins.
Transfer RNA (tRNA): Delivers amino acids to ribosomes during protein synthesis.

Transcription: The enzymatic process in the nucleus that synthesizes RNA from a DNA template.
Codon: A triplet of nitrogen bases in mRNA representing a specific amino acid; determines the sequence in proteins.
Translation: The process where ribosomes convert the mRNA sequence into a corresponding sequence of amino acids to form proteins.

Mutation: Any alteration or random error in the DNA sequence.
Point Mutation: A mutation resulting from a change in a single base pair within the DNA.
Frameshift Mutation: Occurs when bases are added or deleted from DNA, causing misalignment of codons during translation.
Chromosomal Mutation: Involves larger-scale changes at the chromosome level, affecting gene distribution during meiosis.
Mutagen: Any environmental factor (like radiation, chemicals, or heat) that can induce changes in DNA.

Structure of DNA: Composed of nucleotides which consist of a sugar (deoxyribose), phosphate group, and nitrogen base (A, G, C, T); forms a stable double-helix.
Function of DNA: Encodes information necessary for the synthesis of enzymes and proteins crucial for life processes.

Nucleotide Components:
- Simple sugar: deoxyribose
- Phosphate group: one phosphorus atom bonded to four oxygen atoms
- Nitrogen bases: one of adenine, guanine, cytosine, or thymine.
Backbone Structure: The backbone of the DNA strand is formed by alternating sugar and phosphate groups, while nitrogen bases extend outward.

Separation of Strands: DNA strands unwind at the base pairs.
Base Pairing: Complementary nucleotides are matched to exposed bases.
Bonding of Bases: Enzymes facilitate the bonding of new nucleotides to create complementary strands.
Strand Separation: Resulting in two identical double-stranded DNA molecules.