meiosis and mitosis

• What does meiosis mean?

  To lessen
• What type of cell division is meiosis?

  A special type of cell division
• For what purpose is meiosis specifically used?

  For sexual reproduction
• What effect does meiosis have on the chromosome number?

  Halves the chromosome number
• What do parents produce through meiosis?

  Haploid (n) gametes within germ cells
• If parents are diploid (2n), how many sets of chromosomes do they have?

  Two sets of chromosomes
• What is meiosis and what types of cells does it produce?

  • Type of cell division that produces gametes (sperm and egg)
  • Each gamete has one set of chromosomes
• What forms when an egg (n) and sperm (n) join during fertilization?

  A zygote with two sets of chromosomes (diploid 2n)
• What type of cycle is meiosis part of?

  A constant cycle
• What develops from the zygote?

  The next diploid generation
• What is a karyotype?

  • Homologous chromosomes organized by type
• What are homologous chromosomes?

  Homologous chromosomes are one from each parent organized by type.
• How are homologous chromosomes identified?

  Identified by appearance (banding pattern), length, and centromere position.
• What characteristic helps identify homologous chromosomes?

  Length
• What do homologous chromosomes specify?

  They specify the same traits
• What structural feature distinguishes homologous chromosomes?

  Centromere position
• Can the same genes vary between homologous chromosomes?

  Yes, the same genes might vary between two chromosomes in a pair.
• What are alleles?

  Alleles are alternate forms of a gene.
• What is it called when an individual has two identical alleles for a gene?

  Homozygous
• What would an individual with two blue eye alleles be considered?

  Homozygous
• What is it called when an individual has two different alleles for a gene?

  Heterozygous
• What are the direct processes of Meiosis?

  • G1-S-G2 Phases
  • Nearly identical to phases during mitosis
• What occurs during the G1 phase of meiosis?

  Cell growth
• What is the second phase of interphase called?

  S Phase
• What happens during the S Phase of meiosis?

  Cell copies or replicates the DNA of the chromosomes
• What occurs during the G2 Phase of meiosis?

  Cell undergoes final preparations for mitosis
• What is the M phase in meiosis?

  • Prophase 1
  • Prometaphase
  • Metaphase 1
  • Anaphase 1
  • Telophase/Cytokinesis
• What occurs during Prophase 1 of meiosis?

  Homologous alleles pair by synapsis
• What is formed when homologous chromosomes pair?

  A tight pair of homologous chromosomes
• What does synapsis refer to in meiosis?

  The pairing of homologous alleles during Prophase 1
• How are genes aligned on homologous chromosomes during synapsis?

  Genes on chromatids of homologous chromosomes are perfectly aligned
• What complex holds homologous chromosomes together during synapsis?

  The synaptonemal complex
• What is crossing over in meiosis?

  • Mother and father have different traits but the same genes cross over each other
• What occurs during Prometaphase of meiosis?

  Spindle fibers attach to the kinetochores
• Where are kinetochores located on chromosomes?

  At the centromeres of chromosomes
• What structures attach to spindle fibers during Prometaphase?

  Kinetochores
• What are MTOCs in animal cells?

  Centrosomes
• Where do spindle fibers originate from?

  MTOCs
• At what ends of the cell are centrosomes located?

  Opposite ends of the cells
• What happens to homologous chromosomes as they attach to spindle fibers?

  Each homologous chromosome in a pair attaches to spindle fibers