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CKS Genetic Mutations: Unit Overview

  • Focus on genetic mutations, their types, and implications on proteins

Understanding Genes and DNA

  • Gene: A segment of DNA, the genetic code (blueprint of the body).

  • DNA Structure: Similar to LEGO blocks; determines body structure and function.

What is a Genetic Mutation?

  • Definition: A random change in the DNA sequence (nucleotide order).

  • Causes: Mutagens (e.g., smoking, radiation).

Types of Genetic Mutations

  • Substitution: One base is exchanged for another.

  • Insertion: Extra base(s) are added into the DNA sequence.

  • Deletion: One or more bases are removed from the sequence.

Detailed Mutation Examples

Substitution Mutations

  • Overview: One nucleotide replaces another, altering the DNA sequence:

    • Example: Original sequence changes from TAC to TAC -> C substituted for A resulting in the new sequence.

Insertion Mutations

  • Overview: Inserting one or more nucleotides into a sequence:

    • Example: Adding guanine before a specific base yields a new sequence.

Deletion Mutations

  • Overview: Removing nucleotides from the sequence:

    • Example: Deleting a base like G early in the sequence alters the overall coding for proteins.

Effects of Mutations on Proteins

  • Changes in mutation can lead to modifications in the resultant proteins:

    • Some mutations may be silent (no effect on amino acids), missense (leading to a change in one amino acid), or nonsense (early STOP codon).

Categories of Mutations

  • Silent Mutation: No change in the resulting amino acid.

  • Missense Mutation: Alters one amino acid in the protein sequence.

  • Nonsense Mutation: Introduces a premature STOP codon, truncating the protein.

  • Frameshift Mutation: Causes the reading frame of the codons to shift, affecting several subsequent amino acids.

Implications of Genetic Mutations

  • Beneficial Mutations: Can enhance survival (e.g., camouflage in animals).

  • Negative Mutations: May lead to diseases or genetic disorders (e.g., sickle cell anemia).

  • Neutral Mutations: No significant effect on organism's fitness.

The Central Dogma: DNA, RNA, and Protein Synthesis

  • Process Overview: DNA transcribes into mRNA, which is translated into proteins.

    • Transcription: DNA to mRNA.

    • Translation: mRNA to protein at the ribosome.

  • Importance of DNA bases and mutations in affecting the resulting polypeptides.

DNA and RNA Comparison

  • DNA: Double-stranded, contains thymine, deoxyribose sugar.

  • RNA: Single-stranded, contains uracil, ribose sugar.

Cellular Processes and Transport

  • Homeostasis at the cellular level is maintained by cell membranes:

    • Selective Permeability: Controls what enters and exits the cell.

  • Types of transport: Passive transport (no energy) and active transport (requires ATP).

Review of Cell Types

  • Prokaryotic Cells: No nucleus, smaller, simpler structure.

  • Eukaryotic Cells: Have a nucleus, larger, complex structures with specialized organelles.

Basic Cell Theory

  • All living things consist of cells, which are the fundamental unit of life.

  • Cells arise from pre-existing cells.

Biomolecule Overview: Key Components

  • Biomolecules: Include carbohydrates, lipids, proteins, and nucleic acids (RNA/DNA).

  • Each has unique functions essential for life processes.

Final Thoughts

  • Understanding genetic mutations is crucial for comprehending molecular biology, genetics, and their implications on health and disease.