Biology

• What is a Eukaryotic cell?

  A cell with a nucleus and this includes all plant cells and animal cells
• A prokaryotic cell is a cell that does not have a nucleus and is smaller than a Eukaryotic cell
• What is the difference between a plant cell and an animal cell?

  A plant cell has a vacuoel, cell wall and chloroplasts whereas animal cells lack these structures.
• What does a Prokaryotic cell have instead of a nucleus?

  A loop of DNA
• What is the equation for magnification?


  Magnification=image size/real size
• An onion cell is viewed under a microscope with x100 magnification. The image of the cell is 7.5 mm wide, What is the real width of the onion cell?give your answer to um

  75um
• You need to know how to prepare your slide for the onion practical.

  1)Add a drop of water to the middle of the clean slide

  2)Cut up an onion and use tweezers to separate the epidermal tissue from the rest of the onion

  3)Place this onto the slide

  4)Stain the slide with iodine solution so we can see the image clearer

  5)Put a cover slip over the stained epidermis by tilting and lowering it without getting any bubbles under the cover slip
• You need to know how to look through the microscope

  1)Clip the slide you've just prepared onto the stage

  2)Select the lowest power objective lens

  3) Use the course adjustment knob to move the stage up

  4)Use they eyepiece while slowly moving the stage down until the image is in focus

  5)You should use the fine adjustment knob to focus the image so you can see the image clearly

  6)If you need to see a slide with greater magnification, swap the objective lens to a higher power