bio unit 2

• How many chromosomes are in the human body?

  46, arranged in 23 pairs
• What are diploid cells?

  2 matching sets of chromosomes
• What is a chromosome complement?

  The number of chromosomes a cell contains
• What is the name for identical chromosomes?

  Sister chromatids
• How do chromatids connect?

  They join together at the centromere
• Why is cell division important for multicellular organisms?

  To produce new cells for growth and repair
• Why is cell division important for unicellular organisms?

  To form a complete copy of themselves
• What is mitosis?

  Process of diploid cell dividing
• What is mitosis controlled by?

  The nucleus
• What is produced during mitosis?

  Two identical daughter cells
• What is kept the same in mitosis?

  The diploid chromosome complement
• Why is the number of chromosomes kept the same in mitosis?

  So no information is lost
• What happens during mitosis stage 1?

  Chromosome duplicates forming chromatids
• What happens during mitosis stage 2?

  Nuclear membrane breaks down and spindle fibers attach
• What happens during mitosis stage 3?

  Spindle fibers contract, pulling sister chromatids apart
• Where do the sister chromatids move during mitosis?

  To either end of the cell, known as poles
• product of mitosis

  2 nuclear membranes from containing same number of chromosomes as parent cell
• what are stem cells in animals

  unspecialised cells which can divide by mitosis to self renew
• why is mitosis important for stem cells

  to keep their population constant even if they become specialised
• what are stem cells involved in

  growth and repair
• what potential do stem cells have

  to become diff specialised types of cell in animals
• name a stem cell

  embryonic stem cells
• what are embryonic stem cells

  cells derived from embryos that develop from eggs that have been fertilised in a lab
• what are tissue stem cells

  found among other differentiated cells in a tissue or organ
• where are tissue stem cells found

  bone marrow, brain, skeletal muscle, blood vessels, skin, liver, teeth and heart
• benefit of tissue stem cell

  regenerates surrounding cells damaged by disease and injury
• what is a tissue

  group of cells
• what is an organ

  group of tissues
• whats an organ system

  group of organs
• what does an organ contain and why

  contains cell specialised for a particular function and groups of organs work together to form systems
• name the 3 parts of the brain

  cerebrum, medulla, cerebellum
• function of cerebrum

  site of conscious thought, reasoning and imagination
• function of medulla

  carries out and regulates life sustaining functions such as breathing, swallowing and heart rate
• function of cerebellum

  controls balance and coordination of muscles
• Why are multicellular organisms made up of different types of cells?

  Each cell is shaped to suit its function
• Name some specialized cells in multicellular organisms.

  • Nerve cell
  • Red blood cell
  • Sperm cell
  • Root hair cell
  • Palisade mesophyll cell
• What is the function of a nerve cell?

  Long, thin cytoplasm allows communication
• What is the function of a red blood cell?

  No nucleus allows oxygen transport
• What is the function of a sperm cell?

  Male sex cell with a tail to swim
• What is the function of a root hair cell?

  Extended cytoplasm increases surface area for absorption