biology cell and membranes

• Benedict's test for glucose is present goes to blue to ?

  black
• iodine test for starch present goes from brown to ?

  blue/black
• what is the role of the nucleus?


  controls the activity of the cell and contains genes that carry instructions to make proteins and new cells
• what is the role of cytoplasm ?

  • a liquid gel and where most chemical reactions take place
• what is the role of mitochondria ?

  site of aerobic respiration and where energy is released
• what is the role of ribosomes ?

  site of protein synthesis
• what is the role of the cell membrane?

  controls what goes in and out the cell
• what is the role the permanent vacuole?


  filled with cell sap and helps keep the cell rigid
• what is the role of the cell wall?


  made of cellulose and strengthens the cell and helps give it support
• what is the role of the chloroplast?

  contain chlorophyll which absorbs light and is the site of photosynthesis
• what 3 structures are only found in the plant cell?

  permanent vacuole, cell wall and chloroplast
• where does aerobic respiration take place ?


  mitochondria
• what cell structure is responsible for making proteins?

  ribosomes
• what is a specialised cell?

  a cell that can be adapted to do there job and is more efficient at its job
• why do red blood cells have biconcave shape?

  to increase surface area and no nucleus to allow more haemoglobin
• what is the role of the red blood cell?

  to transport oxygen around the body
• what are two factors that effect diffusion?

  temperature and surface area
• what is a semi permeable membrane?


  something that only allows certain substances pass through
• what are two advantages of light microscope ?

  cheap and easy to use
• what are disadvantages of light microscopes~?

  low resolution
• what is an advantage of electron microscope ?

  provides higher magnifications and high resolution
• what are two disadvantages of electron microscopes ?

  cannot be used on living cell and expensive and hard to use
• what is osmosis ?

  Osmosis is the movement of water from a dilute solution to a more concentrated solution across a partially permeable membrane.
• what is active transport ?

  movement of particles from a low to high concentration across a semi permeable membrane and requires energy
• what is an enzyme ?

  protein molecule that speeds up chemical reactions
• what happens when enzyme heat up?

  the have more kinetic energy so the rate of reaction increases
• what happens if the enzyme gets too hot?

  its denatures
• ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ what happenes if the enzyme denatures ?


  the active site changes so the substrate no longer fits