Cell division

• Where do we find chromosomes in a cell?

  In the nucleus
• What are chromosomes made of?

  DNA
• How many chromosomes do human body cells contain?

  46 chromosomes, or 23 pairs
• What determines many of our features such as eye color?

  Genes
• What is the role of the cell cycle in multi-cellular eukaryotic organisms?

  • Supply of new cells for growth
  • Development
  • Repair
• What is the process through which new cells are created called?

  The cell cycle
• How can the cell cycle be thought of?

  As the time it takes for a cell to divide into new cells
• What types of cells can divide by mitosis or meiosis?

  Animal and plant cells
• What are the three stages of mitosis?

  1. DNA replication to form two copies of each chromosome
  2. Mitosis occurs, pulling one set of chromosomes to each side of the cell and dividing the nucleus
  3. Cytoplasm and cell membrane divide to form two identical daughter cells
• What happens during the first stage of mitosis?

  DNA replication occurs to form two copies of each chromosome
• What happens to the chromosomes during mitosis?

  One set of chromosomes is pulled to each side of the cell
• What is formed at the end of the mitosis process?

  Two identical daughter cells
• How many pairs of chromosomes are present in each daughter cell after mitosis?

  2 pairs of chromosomes
• What is the role of mitochondria and ribosomes during the cell cycle?


  They are copied as the cell grows
• How does the process of mitosis ensure genetic consistency in daughter cells?

  By replicating DNA so each daughter cell receives an identical set of chromosomes
• Mitosis

  A type of cell division that results in two daughter cells having the same number and kind of chromosomes as the parent cell
• Chromosomes

  Thread-like structures made up of DNA and proteins, carrying genetic information
• What is one essential function of mitosis in multicellular organisms?

  Mitosis is essential for growth and development.
• How does mitosis contribute to the healing process in organisms?

  Mitosis occurs when an organism repairs itself, such as when a broken bone heals.
• In what type of reproduction does mitosis occur?

  Mitosis occurs during asexual reproduction.
• What are the main functions of mitosis?

  • Essential for growth and development of multicellular organisms
  • Repairs damaged tissues (e.g., healing broken bones)
  • Occurs during asexual reproduction
• What is the primary purpose of meiosis?

  To produce gametes, such as sperm and egg cells
• How many haploid gametes are produced at the end of meiosis?

  4 haploid gametes
• What type of cell do we start with in meiosis?

  A diploid cell
• Why is it important for gametes to be fertilized?

  Because fertilization produces a fertilized egg or zygote
• What happens to the chromosome number during fertilization?

  The zygote has the diploid number of chromosomes
• What is the genetic composition of all gametes produced by meiosis?

  All gametes are genetically different
• What does it mean for gametes to be haploid cells?

  They contain half the genetic material of a body cell
• What are the steps of meiosis?

  1. Replication of all chromosomes
  2. Chromosome pairs align and are pulled apart
  3. Random distribution of chromosomes
  4. Chromosomes line up again, arms are pulled to each side
  5. The cell divides, resulting in 4 cells
• How many chromosomes are in each gamete produced by meiosis?

  23 chromosomes
• What do sperm and egg cells develop from in animals?

  They develop from gametes produced by meiosis
• What happens when a sperm and egg fuse during fertilization?

  They form a diploid cell that can divide by mitosis
• What is the result of fertilization in terms of chromosome number?

  The cell now has the normal diploid number of chromosomes
• Why is it important that cells produced by meiosis have half the number of chromosomes as a body cell?

  If they didn't, the zygote would have 92 chromosomes, leading to unsuccessful pregnancy
• What is fertilization?

  • Fusion of the nucleus of a male gamete with the nucleus of a female gamete
  • Produces a new cell called a zygote
  • Zygote undergoes division to form an embryo
• What is the term for the new cell formed after fertilization?

  Zygote
• What happens to the zygote after fertilization?

  It divides to form an embryo
• What is the role of fertilization in sexual reproduction?

  It restores the normal number of chromosomes in the new cell
• What type of reproduction involves the fusion of gametes?

  Sexual reproduction
• What is the significance of the number of chromosomes in the zygote?

  It ensures successful development of the organism