Bio unit 2

• How do micro-organisms grow in number?

  By cell division (mitosis)
• Why is cell division essential for multicellular organisms?

  It allows growth and repair of damaged cells
• What is one way multicellular organisms use cell division?

  To grow
• What is another way multicellular organisms use cell division?

  To repair damaged parts
• What are chromosomes?

  Structures that determine an organism's characteristics
• How many sets of chromosomes do diploid cells have?

  Two matching sets (46 chromosomes)
• What form of cell division produces new cells?

  Mitosis
• What does a parent cell produce as a result of mitosis?

  Two identical daughter cells
• How many chromosomes do the identical cells produced by cell division have?

  The same number as the parent cell
• What is the sequence of events in mitosis?

  1. Chromosomes become visible as two chromatids
  2. Chromosomes shorten and thicken
  3. Chromosomes line up at the equator, held by spindle fibers
  4. Chromatids are pulled apart to the poles of the cell
  5. A nuclear membrane forms around each set of separated chromosomes and the cytoplasm divides
• What are stem cells?

  Cells involved in growth and repair
• What role do stem cells play in multicellular organisms?

  They are involved in growth and repair
• What are some potential uses of stem cells in medicine?

  Regenerative therapies and disease treatment
• What ethical issues surround the use of stem cells?

  Debates on the source and use of embryos
• What is a cell?

  The basic unit of life
• What is a tissue?

  A group of similar cells
• What is an organ?

  A structure made of different tissues
• How do cells in multicellular organisms become specialized?

  To perform particular functions
• How is the structure of a specialized cell related to its function?

  Structure is adapted for specific tasks
• What hierarchy exists in multicellular organisms?

  Cells → Tissues → Organs → Systems
• What type of cells are diploid?

  All cells except gametes
• What is the difference between haploid and diploid cells?

  Haploid cells have one set, diploid have two
• What are the male and female gametes in animals?

  Sperm and egg
• What are the male and female gametes in plants?

  Pollen and ovule
• What are the structures and functions of the human male reproductive system?

  Includes testes, vas deferens, and penis
• What are the structures and functions of the human female reproductive system?

  Includes ovaries, uterus, and vagina
• What is fertilization?

  Fusion of nuclei of two haploid gametes
• What is a zygote?

  A diploid cell formed after fertilization
• What is continuous variation?

  Variation where measurements vary continuously
• What is discrete variation?

  Variation that falls into distinct groups
• What types of graphs represent continuous variation?

  Line graphs
• What types of graphs represent discrete variation?

  Bar graphs
• What is the difference between single gene and polygenic inheritance?

  Single gene shows discrete, polygenic shows continuous
• What does single gene inheritance show?

  Discrete variation with distinct groups
• What does polygenic inheritance show?

  Continuous variation where measurements vary
• What is a gene?

  A unit of heredity
• What is an allele?

  A variant form of a gene
• What is a genotype?

  The genetic makeup of an organism
• What is a phenotype?

  The physical appearance of an organism
• What does homozygous mean?

  Having two identical alleles