b1

• a eukaryotic cell contain genetic material in a nucleus. they are found in fungi, animals, plants and protists. they are complex cells and are 10-100 micrometres in diameter


  what is a eukaryotic cell?
• what is a prokaryotic cell?

  they dont contain a nucleus and are basic cells.they are 0.1-5 micrometres
• function of nucleus

  contains genetic information and is called the control centre as it controls the activities of the cell
• function of cell membrane


  barrier that controls what goes in and out of the cell.it is selectively permeable and has receptor molecules on the outside
• function of ribosomes

  responsible for protein synthesis
• function of mitochondria

  the powerhouse of the cell. this is where respiration occurs, they contain enzymes for aerobic respiration which releases energy
• function of cytoplasm

  'jelly like' substance where chemical reactions take place
• function of vacuole

  full of cell sap. it helps to keep the cell rigid, so supporting the plant and keeping it upright.
• function of chloroplast


  contain green chlorophyll which is needed for photosynthesis
• function of cell walls

  surrounds the cell and is made of cellulose. it makes the cell rigid and supports the cell
• where are stem cells found?

  bone marrow
• where are plant stem cells found

  meristems
• adv of embryonic stem cells over adult stem cells

  -embryonic stem cells can differentiate into any type of cell whereas adult stem cells can only differentiate into some
• adaptations of a sperm cell

  -flagellum= aid to movement
• adaptations of red blood cell

  -no nucleus=more space for haemaglobin -bioncave disc=larger sa:v ratio so faster rate of diffusion -more haemaglobin= more to bind with oxygen
• resolution of an electron microscope

  0.1μm
• resolution of a light microscope

  0.2μm
• how does an transmission electron microscope(TEM) work

  a beam of electrons pass and produce an image, they produce the most magnified image
• how does a scanning electron microscope (SEM) work?

  it produces a 3D image and sends a beam of electrons to form an image.
• define resolution


  ability of a microscope to distinguish details of a specimen or sample
• define magnification


  how many times larger an image seen through a microscope is compared to the real object.
• why do we stain cells

  makes it easier to observe subcellular structures
• advantage of electron microscope


  -higher resolution
• disadvantages of electron microscope


  -expensive

  -not portable

  -specimens have to be dead
• light microscope experiment

  • Put a thin sample of tissue onto a microscope slide.
  • Add a few drops of a suitable stain/dye.
  • Place a coverslip on top of the tissue and place the slide onto the microscope stage.
  • Use the objective lens with the lowest magnification, and focus on the sample.
  • Increase the magnification and refocus to see different features of the cell.
• • Eukaryotic
  • Plants, animals, fungi, protists
  • 10-100 µm
  • Prokaryotic
  • Bacteria
  • 0.1-5.0 µm
• how many molecules of ATP does aerobic respiration make?

  38
• how many molecules of ATP does anaerobic respiration

  2
• define metabolic rate


  the speed at which chemical reactions transfer energy from its chemical stores in food
• adv of aerobic respiration over anaerobic respiration


  -more molecules of ATP are made because glucose is fully broken down

  -no lactic acid produced(toxic)
• what is the first stage of photosynthesis


  -light dependent

  -energy transferred from light splits water molecules into oxygen gas and hydrogen ions.
• what is the second stage of photosynthesis


  -light independent

  -carbon dioxide gas combines with hydrogen ions to make glucose.
• uses of glucose


  -sucrose=stored in fruit

  -glucose=respiration

  -starch=food store

  -proteins=growth and repair

  -fats and oils=food store and growth
• adaptations of a sperm cell


  -flagellum= aid to movement

  -contain lost of mitochondria=enough energy to move to the egg cell

  -acrosome=the acrosome at the tip of the head contains and enzyme needed to break into the egg cell
• adaptations of a nerve cell


  -long axon=increases the distance that electrical signals can travel

  -myelin sheath=stops signals leaking out of the cell and increases the speed of transmission