topic 2

• What type of cell division results in new body cells being produced?

  Mitosis
• What does diploid mean?

  2 sets of chromosomes
• 3 reasons mitosis is important

  growth, repair, asexual reproduction
• How many daughter cells are produced in mitosis?

  2 daughter cells
• What happens in interphase?

  DNA replicates, cell organelles duplicate
• name the other stages of mitosis

  prophase, metaphase,anaphase, telophase, cytokinesis
• What happens in prophase?

  The nucleus starts to break down and spindle fibres appear
• What happens in metaphase?

  Chromosomes line up at the MIDDLE of the cell.

  Spindle fibers attach to centromere.
• What happens during anaphase?

  The chromosomes separate and move along spindle fibers to opposite ends of the cell
• What happens in telophase?


  Nuclear membrane reforms to form 2 daughter cells

  Chromosomes decondense
• What happens in cytokinesis?


  cytoplasm divides, cell surface membrane separates to form two new cells. In plant cells, cell walls are formed.
• in asexual reproduction what name is given to the offspring?


  Clones
• What is the process where cells become specialised?

  Differentiation
• What is a stem cell?


  an undifferentiated cell that can keep dividing to form more stem cells, or differentiate.
• name 2 ways a red blood cell is specialised?

  Contains haemoglobin to bind oxygen, No nucleus, large surface area, concave shape
• What are the two types of stem cells?

  embryonic stem cells and adult stem cells
• How are stem cells used in medicine?

  Bone marrow transplants can replace adult blood cells
• List 2 potantial risks of stem cell treatments

  Stem cells could divide too rapidly and cause a tumor

  Disease transmission

  rejection by recipient's immune system
• Why might some people disagree with using embryonic stem cells?

  Destroys a "potential life"
• Where are stem cells found in plants?

  Meristems in the tips of the roots and shoots.
• Define growth


  Increase in size as a result of the number of/ size of cells
• Where does growth occur in plants?

  Meristems in the tips of the roots and shoots
• What happens when cells divide uncontrollably?

  A tumor forms. it becomes cancer once it invades surrounding tissues.
• How does growth occur in animals?

  Cell division and diffrentiation
• How does growth occur in plants?

  cell division, diffrentiation and elongation
• What does it mean if a child is on the 75th percentile for height?

  75% of children (the same age) are shorter
• What is the funtion of the nervous system?

  To allow communication between different parts of the body
• Name the organs in hte Central Nervous System (CNS)

  Brain and Spinal Cord
• What is the spinal cord?


  A long column of neurones that connect the brain to the rest of the body
• What is the funtion of a sensory neurone?

  To carry impulses from receptor cells n the sense organs (e.g. skin) to the CNS
• What is the funtion of a mototr neurone?

  To carry impulses from the CNS to the effectors
• What are relay neurones?


  Short neurones found in the spinal cord linking the motor and sensory neurones
• What feature allows impulses to be transmitted quickly along a neurone?

  Long axon. Sensory neurones have a myelin sheath
• What is the function of the myelin sheath?

  Insulates the neurone to stop the impulse losing energy
• Which substance transmits an impulse from one neurone to another?

  Neurotransmitter
• Describe a synapse


  A gap or space between the axon of one neuron and the dendrite of another - this is where neurotransmitters (chemicals) pass the nerve impulse from one neuron to another neuron
• What is the name for a change in the environment that the body reacts to?

  Stimulus
• Describe the path of the reflex arc using parts of the nervous system.

  STIMULUS > receptor cells > sensory neurone > relay neurone> motor neurone > effector > RESPONSE
• What is the advantage of a reflex arc?

  Allows a fast and automatic response to what the body percieves as danger.
• If reaction time is smaller, the response would be ___________ (faster/ slower)

  faster