Cells and control

• what are the stages of the cell cycle

  • interphase
  • prophase
  • metaphase
  • anaphase
  • telophase
  • cytokinesis
• what is mitosis

  cell division that produces two identical diploid daughter cells
• what happens in the interphase

  • the cell grows, the DNA is replicated
• what happens in the prophase

  • the chromosomes condense and so the membrane around the nucleus breaks down
• what happens in the metaphase

  • the chromosomes are pulled to the centre of the cell by spindle fibres
• what happens in the anaphase

  • spindle fibres pull the chromosomes apart and the chromatids are pulled to the opposite ends of the cell
• what happens in the telophase

  • membranes form around each of the sets of the chromosomes. These become the nuclei of the two new cells
• what happens in cytokinesis

  • the cytoplasm and cell membrane divide to form two separate cells
• what stages of the cell cycle is mitosis

  • prophase
  • metaphase
  • anaphase
  • telophase
• what do multicellular organisms use mitosis for

  to grow or to replace cells that have been damaged

  Some organisms use mitosis to reproduce asexual reproduction
• which processes do animals undergo to grow

  • cell differentiation
  • cell division
• which processes do plants undergo to grow

  • cell differentiation
  • cell division
  • cell elongation
• what is cell differentiation

  when a cell changes to become specialised for it's job allowing multicellular organisms to work more efficiently
• what is cell division

  mitosis
• what is cell elongation

  • when the plant cell expands making the cell bigger and so making the plant grow
• describe the processes animals undergo to grow

  • cell division : cells divide at a fast rate but once you're an adult cell division is used for repair
  • cell differentiation : lost at an early stage
• describe the processes plants undergo to grow

  cell division : the tips and shoot grow

  cell differentiation : plants continue to grow and develop new parts

  cell elongation : cells make the height of the plant grow
• what is cancer a result in

  • the rate at which cells divide by mitosis is controlled by genes in DNA
  • if there is a mutation in the cells the cells may divide uncontrollably
  • this can result in a mass of abnormal cells called a tumour
• what can be used to monitor growth

  • percentile charts
• why do cells differentiate

  to become specialised cells
• what are stem cells

  • undifferentiated cells
  • they can divide by mitosis to become new cells which then differentiate
• what are embryoic stem cells

  • formed when an egg and sperm cell fuse to form a zygote
  • they can differentiate into any type of cell in the body
  • scientists can clone these cells (through culturing them) and direct them to differentiate into any cell in the body
• what are adult stem cells

  • bone marrow which can form many types of cells including blood cells
• what are stem cells in plants

  • meristems which are found in the roots and shoot tips
  • this can differentiate into any cell type of plant
• what are the benefits of using stem cells in medicine

  • can be used to replace damaged or diseased cells
  • unwanted embryos can now have a use
• what are the problems of using stem cells in medicine

  • don't fully understand the process of differentiation so it's hard to control stem cells
  • risk of tumour growth as stem cells can divide quickly
• what are the three structures of the brain

  • cerebrum
  • cerebellum
  • medulla oblongata
• where is the cerebrum located

  • top of the brain
• what is the function of the cerebrum

  • consciousness , memory , intelligence , visual and sensory processing
• where is the cerebellum located

  • at the bottom rear of the brain
• what is the function of the cerebellum

  • co-ordination and movement of muscle
• where is the medulla oblongata located

  • in the brainstem, at the base of the brain
• what is the function of the medulla oblongata

  • maintains basic autonomic bodily functions:
  • breathing, digestion, swallowing and sneezing
• how does a CT scan work

  • x-rays are fired at the brain from several different angles to generate a 3D image of the brain
• what are the advantages of CT scan

  • shows the main structures
  • shows whether the structure is diseased or damaged
• what are the disadvantage of CT scans

  • does not show the functions
• how does a PET scan work

  • a radioactive 'tracer' is injected into the blood before the scan
  • the scan is sensitive to the tracer so areas where the tracer builds up ( greater blood flow ) will be highlighted more brightly on the scan
  • helps identify tumours as use more blood than normal tissue
• what are the advantages of PET scans

  • very detailed and can show whether that area of the brain is inactive or active
  • useful for studying disorders that change the brain's activity
• what are the limitations in treating damage and disease in the brain and other parts of the nervous system, including spinal injuries and brain tumours

  • hard to repair damage
  • some parts aren't easily accessible
  • may lead to permanent damage
• what are sensory receptors

  • specialised cells that detect a change in the environment