Biology

• Mitosis


  1. Interphase

  2. Prophase

  3. Metaphase

  4. Anaphase

  5. Telophase

  6. Cytokinesis
• Interphase


  Cell replicates DNA and makes more organelles like mitochondria and ribosomes
• Prophase


  Nucleus breaks down, spindle fibers appear
• Metaphase


  Spindle fibers pull chromosomes to the middle of the cell
• Anaphase


  Spindle fibers pull chromatids to each end of the cell
• Telophase


  Nucleus reforms
• Cytokinesis


  Cytoplasm splits creating two daughter cells
• Mitosis always produces identical cells
• Mistakes in DNA copying during mitosis

  Can cause uncontrolled cell division and tumors
• Growth


  Increase in size or number
• Plant cell growth


  • Cells elongate and divide at the roots
• Animal cell growth


  • Cells typically just divide
• Percentile charts


  Measure growth by comparing to other organisms
• Stem cells


  Unspecialized cells that can differentiate into specialized cells
• Types of stem cells

  • Embryonic
  • Adult
  • Plant
• Embryonic stem cells


  Can turn into any type of specialized cell
• Adult stem cells


  Can only turn into certain types of specialized cells
• Plant stem cells


  Can turn into any type of specialized cell
• Stem cells can be used in medicine to produce needed cell types, but there are risks of tumor growth and immune rejection
• Nervous system


  Sends and receives information
• Parts of the nervous system

  • Central nervous system (brain and spinal cord)
  • Peripheral nervous system (all other neurons)
• Types of nerve cells

  • Sensory neurons
  • Motor neurons
  • Relay neurons
• Sensory neurons


  • Have dendrites, axon, cell body with nucleus and organelles, connect to receptors
• Motor neurons


  • Have dendrites on cell body, axon, axon terminals, carry impulses to muscles and glands
• Relay neurons


  • Short neurons in brain and spinal cord, look like motor neurons
• Myelin sheath


  Insulates neurons and speeds up impulses
• Nerve impulse pathway


  1. Stimulus

  2. Receptor

  3. Sensory neuron

  4. Relay neuron

  5. Motor neuron

  6. Effector (muscle or gland)

  7. Response
• Synapse


  Small gap between neurons where neurotransmitters are released
• Main parts of the brain

  • Cerebrum
  • Cerebellum
  • Brainstem/Medulla oblongata
• Cerebrum


  Makes up the main bulk of the brain, divided into two hemispheres
• Cerebellum


  Responsible for motor functions like walking
• Brainstem/Medulla oblongata


  Responsible for unconscious processes like breathing and heart rate
• CT scan


  Builds up an image of the shapes and structures in the brain using an x-ray beam
• PET scan


  Measures brain activity by detecting radioactive glucose uptake
• Reflex arc


  Allows the body to quickly react to dangerous situations without involving the brain
• Lens


  Focuses light into the eye
• Iris


  Colored part of the eye, controls the pupil
• Pupil


  Hole in the center of the iris that allows light into the eye
• Cornea


  Helps focus light into the eye
• Optic nerve


  Sends visual information to the brain