Biology Chapter 11 - DNA & Genes

Study Notes

Key Concepts in DNA and 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.

RNA Types and Functions

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 and Translation

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.

Mutations and Their Types

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.

DNA Structure and Function

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 Composition

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.

DNA Replication Steps

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.

Description

Test your knowledge on essential terms related to DNA and genes with these flashcards. Covering concepts such as nitrogen bases, the double helix structure, and DNA replication, this quiz helps reinforce key biological vocabulary. Perfect for students studying molecular biology or genetics.