Biology paper 1

• how water acts as a solvent

  water is polar, the positive end of a water molecule will be attracted to the negative ion, and the negative end of a water molecule will be attracted to the positive ion.
• Name the organelles you might find in an animal cell

  1. plasma cell surface membrane
  2. rough/smooth enodplasmic reticulum
  3. nucleus
  4. ribosome
  5. lysosome
  6. golgi apparatus
  7. cytoplasm
  8. mitochondria
• how are fungi different to plant cell

  • fungi cell wall is made of chitin, not cellulose
  • dont have a chloroplast because they dont do photosynthesis
• Name the components of the nucleus

  • nucleolus
  • nuclear envelope
  • nuclear pores
  • chromatin
  • necleoplasm
• Describe the structure of the Golgi apparatus.

  A group of fluid-filled, membrane-bound, flattened sacs. Vesicles are often seen at the edges of the sacs.
• what are the functions of golgi apparatus

  • adds carbohydrates to protein to form glycoprotiens
  • forms lysosomes
  • transport, modify and stores lipids
• golgi vesicles are produced by the golgi apparatus and they transport lipids and proteins out of the cell via the cell surface membrane
• Outline the functions of lysosome

  • contains lysozymes which are enzymes that hydrolyse the cell wall of bacteria
  • digest invading cells
• Outline the functions of Smooth endoplasmic reticulum

  • synthesises and processes lipids
• rough endoplasmic reticulum

  • has ribosomes on its surface
  • provides a large SA for the synthesis of proteins and glycoproteins
  • provides a pathway for transport of materials
• Why is the membrane described as having a fluid mosaic structure?

  flexible structure, as the phospholipids move relative to one another so the membrane can change shape. There are also various proteins embedded in it, of all shapes and sizes, like tiles in a mosaic.
• What is (passive) diffusion?

  Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration.
• What is meant if two solutions are said to be isotonic

  they have the same water potential
• Why are viruses described as being acellular

  • they are not cells.
  • nucleic acids surrounded by protein and are not even alive.