Gametes and Fertilization

• What are the main parts of the human sperm (spermatozoa)?

  • Head
  • Acrosome
  • Midpiece
  • Mitochondria
  • Axoneme
  • Tail/Flagellum
• If you wanted to observe the internal structure of a human egg (ovum) in detail, which microscope would you use?

  Transmission electron microscope
• What are gametes?

  Special cells for sexual reproduction
• How does the movement of sperm differ from that of eggs?

  Sperm is motile, while eggs are stationary
• What is the process of sexual reproduction involving gametes?

  • Gametes join together
  • Sperm from father unites with egg from mother
  • Forms a zygote
  • Zygote grows into a baby
• What is the result of the union of a sperm and an egg?

  A zygote that grows into a baby
• What is meiosis?

  A special type of cell division forming gametes
• What is the function of the acrosome in human sperm?

  The acrosome contains enzymes that help the sperm penetrate the egg during fertilization.
• What are the stages of meiosis as shown in the image?

  • Interphase
  • Meiosis I:
  • Prophase I
  • Metaphase I
  • Anaphase I
  • Telophase I
  • Meiosis II:
  • Prophase II
  • Metaphase II
  • Anaphase II
  • Four daughter cells produced
• What are the two types of gametes mentioned?

  Sperm and ova
• How does the chromosome number change from meiosis I to meiosis II?

  It remains the same, staying haploid
• What do gametes contain from each parent?

  Half of a parent's genetic information
• What is the structure of an egg gamete?

  Core nucleus with jelly coat
• What happens when a sperm unites with an egg?

  It forms a zygote
• What is the purpose of meiosis II?

  • To further separate the chromosomes and divide the cell into four haploid daughter cells
  • To complete the process of meiosis and produce gametes (sperm or eggs)
• What happens after the sperm contacts the zona pellucida?

  Acrosome releases enzymes
• What is the chromosome number in the final products of meiosis II?

  Haploid
• What is the size of sperm gametes?

  Microscopic
• What follows the separation of chromosomes in Meiosis I?

  Cytokinesis where the cell splits
• What is the purpose of the polar body formation during meiosis?

  To discard excess genetic material and maintain the haploid chromosome number
• What happens when the sperm nucleus enters the egg?

  • The sperm nucleus enters the egg cytoplasm
  • The cortical granules of the egg fuse with the egg plasma membrane
  • This renders the vitelline layer impenetrable to other sperm
• What occurs after the sperm penetrates the layers?

  Plasma membranes fuse
• What are the main stages of meiosis II?

  • Prophase II
  • Metaphase II
  • Anaphase II
  • Telophase II
• What happens during Meiosis I?

  Chromosomes pair up and separate
• What is the purpose of the acrosome in the fertilization process?

  • The acrosome reacts with the zona pellucida of the egg
  • This reaction helps the sperm penetrate the egg
• What is the purpose of the hydrolytic enzymes released during the acrosome reaction?

  To help the sperm penetrate the egg
• What is the name of the outermost layer of the human egg (ovum)?

  Corona radiata (follicular cells)
• What is the name of the innermost layer of the human egg (ovum)?

  Nucleus
• What shape is a sperm gamete?

  Tiny, tadpole
• How do the structures of sperm and egg gametes differ?

  Sperm has a head, middle piece, and tail; Egg has a nucleus and jelly coat
• What is the third step in the acrosomal process?

  Sperm penetrates layers
• What is the fifth step in the acrosomal process?

  Nucleus enters egg
• How does the structure of a human egg (ovum) differ from a human sperm (spermatozoa)?

  The egg is much larger and contains more organelles like the nucleus, while the sperm is smaller and more streamlined with a tail for motility
• How many gametes are produced at the end of meiosis?

  Four gametes
• What is the final step in the acrosomal process?

  Cortical granules block further entry
• What is the size of egg gametes?

  Visible to the naked eye
• If a cell undergoes meiosis II, what happens after telophase II?

  No further division
• How does varied traits in offspring affect a species?

  It increases the species' ability to survive and adapt
• What is the zona pellucida?

  The outer layer of the egg
• Why does the acrosome reaction occur?

  To help the sperm penetrate the egg