Topic 1

• What is a stem cell ? 


  Cells that can differentiate into specialised cells
• List the parts of an animal cell

  Ribosomes,mitochondria, cell membrane, nucleus ,cytoplasm,

  
• List the parts of a plant cell

  Nucleus , ribosome , cell membrane ,permanent vacuole , mitochondria ,cell wall, cytoplasm , chloroplast

  
• What is the equation for magnification? 


  image size / real size
• How are sperm cells specialised? 


  flagella - to move fast

  Lots of mitochondri- for energy

  Enzymes in head to digest egg cell membrane

  Streamlined head -aerodynamics
• What are some advantages of a light microscope? 


  The cell can be living

  Cheap

  Easy to move around and use
• Advantages of electron microscopes 


  High magnification

  High resolution
• Disadvantages of light microscopes 


  Low resolution

  Low magnification
• Disadvantages of electron microscopes 


  Risk of radiation leaks

  Expensive

  Cannot move around
• What are the disadvantages of using stem cells from bone marrow ? 


  They can only specialise into specific specialised cells (e.g red blood cells )

  Painful to retrieve
• What is a prokaryotic cell ? 


  Simple cells that do not have a nucleus (bacteria )
• What is a eukaryotic cell ? 


  A cell that has other structures in the cytoplasm which have membranes around them (animal and plant cells )
• What is the definition of DNA ? 


  A molecule that carries genetic information
• How many chromosomes does a human have ? 


  46 (23 pairs )
• Where is the genetic material in a eukaryotic cell found ?

  The nucleus
• What are the uses of stem cells ? 


  replace faulty cells
• animal stem cells found 


  in embryos and bone marrow
• uses of plant stem cells 


  grow more rare plants

  Grow clones of plants

  Grow identical crops
• Plant stem cells are found 


  In the meristems
• What is the advantage of plant stem cells compared to animal cells ?

  Plant cells have the ability to differentiate at any point in the plant lives animals do not
• What are the 3 steps of the cell cycle ? 


  1.growth and DNA replication

  2.further growth and DNA is checked/broken down into chromosomes,nucleus breaks down

  3.Mitosis
• In diffusion , if the surface area to volume ration increases what will happen to the rate of diffusion


  Increases
• What is differentiation ? 


  The process by which a cell changes to become specialised for its job
• What are undifferentiated cells called?


  Stem cells
• How are root hair cells specialised ?

  Large surface area to penetrate soil Large surface area to penetrate soil

  Thin cell wall to creat a shorter diffusion distance

  Lots of mitochondria
• How are muscle cells specialised ? 


  Lots of mitochondria for energy so they can contract quickly

  Long to have space to contract
• How are nerve cells specialised ? 


  Long to rich large distances

  Branched connections
• what are the steps of mitosis ? 


  1. Chromosomes line up in the middle of the cell
  2. chromosomes are pulled to the opposite sides of the cell by cell fibres
  3. Two new nuclea membranes form around the chromosomes at each of the cell
  4. The cell splits down the middle to form two new daughter cells
• how are xylem and phloem cells specialised ? 


  Long joined together cells

  Xylem cells die and hollow

  Phloem have few sub cellular structures

  To allow substances to flow through