Chapter 10 Supplementary pp

Introduction to Genetics

  • DNA and genes are crucial for understanding genetic disorders (e.g., color blindness, cystic fibrosis).

  • Mendelian genetics helps explain inheritance patterns.

DNA Structure and Function

  • DNA: thread-like molecule, 46 chromosomes in human cells, composed of nucleotides (sugar, phosphate, base).

  • Double helix with base pairing: A-T (2 bonds), C-G (3 bonds); ~20,000 genes code for proteins.

Discovery of DNA Structure

  • Developed from various scientists' contributions (e.g., X-ray diffraction).

Chromatin and Chromosomes

  • Chromatin is DNA and protein complex; histones pack DNA.

RNA Structure and Function

  • RNA (mRNA, rRNA, tRNA) is vital for protein synthesis and contains ribose and uracil.

Genetic Code and Protein Synthesis

  • Codons (3-base sequences) translate DNA to proteins, with 64 codons for 20 amino acids.

  • Transcription and translation convert DNA to proteins.

Gene Regulation

  • Genes can be activated or repressed by external conditions.

DNA Replication

  • Necessary for cell division; involves semiconservative replication.

Cell Cycle and Mitosis

  • Includes interphase (G1, S, G2) and mitotic phase, creating identical cells.

Regulation of Cell Division

  • Controlled by cyclins and kinases under specific conditions.

Heredity and Variation

  • Karyotype: 46 chromosomes in 23 pairs; alleles can be dominant or recessive.

  • Genetic variation affects health with multiple alleles and polygenic traits.

Cancer Biology

  • Cancer cells divide rapidly and metastasize; oncogenes and tumor-suppressor genes regulate growth.