exam 4 study

• Cell Cycle

  1. G1 (Gap 1)

  2. S (Synthesis)

  3. G2 (Gap 2)

  4. M (Mitosis)
• G1 phase

  Cell grows and carries out normal functions
• S phase

  DNA replication
• G2 phase

  Further growth and preparation for mitosis
• Mitosis (M phase)

  Cell divides its nucleus and cytoplasm to produce two daughter cells
• Stages of Mitosis

  1. Prophase

  2. Prometaphase

  3. Metaphase

  4. Anaphase

  5. Telophase
• Prophase

  • Chromosome condensation, nuclear envelope breakdown, and spindle apparatus formation
• Prometaphase

  • Chromosome attachment to spindle fibers
• Metaphase

  • Chromosome alignment at the metaphase plate
• Anaphase

  • Sister chromatids separate and move to opposite poles
• Telophase


  • Chromosome decondensation, nuclear envelope reformation, and cytokinesis
• Stages of Meiosis

  1. Prophase I

  2. Metaphase I

  3. Anaphase I

  4. Telophase I

  5. Prophase II

  6. Metaphase II

  7. Anaphase II

  8. Telophase II
• Prophase I

  • Homologous chromosome pairing and crossing over
• Metaphase I

  • Alignment of homologous pairs at the metaphase plate
• Anaphase I

  • Separation of homologous chromosomes to opposite poles
• Telophase I

  • Two haploid daughter cells
• Prophase II, Metaphase II, Anaphase II, and Telophase II are similar to mitosis but produce four haploid daughter cells
• MPF (Maturation-Promoting Factor)

  A complex of cyclin and cyclin-dependent kinase that peaks during mitosis
• Cyclins and CDKs

  • Regulate the cell cycle by phosphorylating target proteins
  • Their concentrations fluctuate during different mitotic stages
• Cyclin levels

  Rise and fall at specific checkpoints
• Cancer cells


  • Divide uncontrollably, evade apoptosis, and metastasize
  • Exhibit genomic instability and abnormal cell cycle regulation
• Normal cells

  • Have regulated division and undergo apoptosis when necessary
• Benign tumors

  Localized and non-invasive
• Malignant tumors


  Can invade surrounding tissues and metastasize
• Benign tumors do not migrate to other sites, while malignant tumors can spread
• Chromosomes

  • Consist of two sister chromatids held by a centromere
  • Each chromatid carries identical genetic information
• Somatic cells

  Undergo mitosis and are diploid (2N)
• Gametic cells

  Undergo meiosis and are haploid (N)
• Somatic cells have pairs of homologous chromosomes, while gametic cells have single sets
• Allele


  Alternative form of a gene
• Trait

  Characteristic determined by genes
• Phenotype

  Observable traits
• Genotype

  Genetic makeup
• Heterozygous

  Has two different alleles
• Homozygous

  Has two identical alleles
• Dominant alleles

  Mask recessive ones
• Recessive alleles

  Are masked
• Punnett square predicts genotypes of offspring
• Apoptosis

  Programmed cell death involving DNA and protein fragmentation, leading to the formation of apoptotic bodies
• Cell Signaling Stages

  1. Signal reception

  2. Signal transduction

  3. Cellular response