Gene Regulation and Mutations

Gene Regulation & Mutations

Essential Question: What are the causes and effects of changes in gene activity and DNA?

Gene Regulation: Control over gene expression.
Cell Differentiation: Process where unspecialized cells develop into specialized cells.
Operon: A section of DNA with genes for proteins that work together for a specific function.
Mutation: A permanent change in DNA.
Mutagen: An agent that causes mutations.

Definition: The ability of an organism to control gene expression in response to signals.
Functionality:
- Allows different cell types (e.g., brain cells vs. muscle cells) to perform specific functions.
- Supports rapid reactions to environmental changes.
- Primarily occurs during transcription.
Operon Example: Lac operon in bacteria is only expressed in the presence of lactose, allowing for lactose digestion.
Human Example: Insulin gene activation occurs in response to high blood sugar levels.

Differentiation: Cells are specialized to produce distinct gene products (proteins).
Stem Cells: Unspecialized cells capable of differentiating into any cell type.
Impact of DNA and RNA: Determine gene expression patterns; influenced by environmental factors.
Environmental Factors: Can cause mutations or alter gene expression:
- External: Radiation, toxins, temperature, nutrition.
- Example: Fetal Alcohol Syndrome from maternal alcohol use.
Internal Factors: Hormones can influence gene expression, e.g., gene activation during puberty.

Definition: Permanent changes in DNA that affect gene sequences.
Types of Mutations:
- Substitutions: One base is exchanged for another; can lead to missense or nonsense mutations.
- Insertions and Deletions: Additions or losses of nucleotides causing frameshift mutations.
Examples:
- Sickle-cell Disease: Mutation in hemoglobin gene alters red blood cell shape.
- Tay-Sachs Disease: Mutation in the HEXA gene leads to the buildup of nerve-damaging substances.
- Cystic Fibrosis: Caused by a deletion in the CFTR gene leading to thick mucus production.

Spontaneous Mutations: Errors in DNA replication caught by proofreading enzymes.
Mutagens: External agents like radiation that cause mutations.
- Examples: High-energy radiation and UV radiation affecting DNA structure.

Genetic Variation: Essential for evolution; can lead to beneficial traits.
Beneficial Mutations: Examples include lactose tolerance, disease resistance, and plant growth advantages.