Biology Final Exam Study Guide Notes

Mitosis

  • Asexual cell division that produces two genetically identical diploid cells.
  • Used for:
    • Growth
    • Repair
    • Replacement of cells
  • Phases (PMAT + Cytokinesis):
    • Prophase:
      • Chromosomes condense
      • Nuclear membrane dissolves
      • Spindle forms
    • Metaphase:
      • Chromosomes line up at the center
    • Anaphase:
      • Sister chromatids separate
    • Telophase:
      • New nuclei form
      • Chromosomes uncoil
    • Cytokinesis:
      • Cytoplasm divides
      • In animals: pinching in
      • In plants: cell plate forms

Meiosis

  • Produces four unique haploid gametes for sexual reproduction.
  • Reduces chromosome number by half.
  • Key Features:
    • Two divisions (Meiosis I and II)
    • Crossing over (Prophase I) and Independent Assortment (Metaphase I)
    • Results in 4 gametes, all genetically different.

Cell Cycle

  • Four phases:
    • G1: Cell grows and functions.
    • S: DNA replicates.
    • G2: Prepares for mitosis.
    • M: Mitosis and cytokinesis.
  • Interphase = G1 + S + G2
  • Checkpoints ensure correct progression.

Chromosome Structure

  • Two identical sister chromatids.
  • Centromere in the middle.
  • DNA wrapped around histones to form chromatin.
  • Telomeres on ends protect DNA.

Mendelian Genetics

  • Gregor Mendel discovered laws of inheritance using pea plants.
  • Key Terms:
    • Gene
    • Allele
    • Dominant
    • Recessive
    • Genotype
    • Phenotype
  • Law of Segregation: alleles separate during gamete formation.
  • Law of Independent Assortment: genes are inherited separately.

Other Patterns of Inheritance

  • Incomplete Dominance: blending (red + white = pink)
  • Codominance: both alleles show (AB blood)
  • Multiple Alleles: more than two (A, B, O)
  • Polygenic Traits: controlled by many genes (e.g., height)
  • Sex-linked Traits: carried on X or Y (e.g., colorblindness)

Circulatory System

  • Capillaries: Tiny vessels where diffusion of gases and nutrients occurs.
  • Blood Pressure: Force of blood; 120/80120/80 normal.
  • Arteries: Carry blood away; thick walls.
  • Veins: Carry blood to heart; valves prevent backflow.
  • Red Blood Cells: Carry oxygen using hemoglobin.
  • Hypertension: High blood pressure.
  • Stroke: Brain damage from blocked or burst vessel.

Digestive System

  • Stomach: Churns food; adds acid and pepsin.
  • Pancreas: Makes enzymes, insulin, glucagon.
  • Liver: Produces bile, detoxifies blood, stores nutrients.
  • Peristalsis: Muscle contractions pushing food through the digestive tract.
  • Ulcer: Open sore in stomach lining; often caused by H. pylori.