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PBS_222_AProteinProblem

A Protein Problem

Overview of Genetic Disorders

  • Genetic disorders: Health conditions caused by changes in DNA sequences affecting genes.

    • Example: Neurofibromatosis type 1 (NF1).

    • Affected by mutations in the DNA sequence.

Key Concepts of Genetic Disorders

  • Gene mutations: Changes in the sequence of DNA bases (A, T, C, G) that can lead to disorders.

  • Importance of genetic testing for diagnosing conditions like NF1.

Protein Primer

Role of Proteins in the Body

  • Proteins are essential biomolecules; the building blocks of life.

  • A typical human cell contains at least 10,000 different proteins.

Functions of Proteins

  1. Driving Cellular Reactions: Facilitate digestion and biosynthesis.

  2. Providing Defense: Antibodies combat pathogens.

  3. Building Structures: Include silk, collagen, and keratin.

  4. Transporting Materials: Hemoglobin carries oxygen and cellular waste.

  5. Coordinating Cellular Activities: Hormonal proteins maintain homeostasis (e.g., insulin).

  6. Movement: Motor proteins like actin and myosin facilitate muscle movement.

Protein Synthesis

  • The process by which proteins are generated from DNA instructions.

  • A gene is a sequence of DNA that codes for a protein.

  • NF1 gene: Found on chromosome 17; produces neurofibromin, regulating cell growth and division.

Steps in Protein Synthesis

  1. Transcription: DNA is transcribed into messenger RNA (mRNA).

  2. Translation: mRNA is translated into an amino acid sequence to form proteins.

Types of RNA

  • DNA vs RNA Comparison:

    • DNA: Double-stranded, deoxyribose sugar, bases A, T, C, G.

    • RNA: Single-stranded, ribose sugar, bases A, U, C, G.

  • mRNA: Carries genetic information from DNA for protein synthesis.

Mutations and Their Effects

  • Types of mutations:

    1. Substitutions: One DNA base is swapped for another.

    2. Insertions: Additional DNA bases are added.

    3. Deletions: DNA bases are removed.

  • Impacts of mutations can include non-functioning proteins or altered protein functions, affecting health.

Specific Example: Sickle Cell Anemia

  • Caused by a substitution mutation in the hemoglobin gene.

  • A change from adenine to thymine alters the protein's shape, leading to sickle-shaped red blood cells.

Diagnosing Genetic Disorders

  • Genetic testing helps confirm diagnoses like NF1 by comparing gene sequences.

  • Geneticists analyze mutations and their consequences for health and development.

Importance of Genetic Testing

  • Vital for understanding genetic disorders and preparing for future health impacts.

  • Helps inform patients and families about management and prognosis of conditions like NF1.

Conclusion

  • Understanding DNA, mRNA, protein synthesis, and mutations is critical for diagnosing and addressing genetic disorders.

  • Changes in a single nucleotide can significantly affect health and function.