Biology paper 1

• Magnification of light microscope

  X1500
• Resolution of light microscope

  0.2micrometers
• Magnification of a scanning electron microscope

  X500000
• Resolution of scanning electron microscope

  0.002 micrometers
• Magnification of a transmission electron microscope

  X1,000,000
• Resolution of a transmission electron microscope

  0.0002 micrometers
• What can be used as a counterstain

  safranin dye
• Magnification


  How many times larger the image is than the actual size of the object being viewed
• Resolution


  How detailed the image is. How well the microscope distinguishes between 2 points that are close together.
• Nucleolus


  Produces ribosomes. Made of protein and RNA, which is used to make rRNA, which combines with protein to form ribosome.
• What's the plasma membrane made off

  Many lipids and proteins
• Centrioles


  Small, hollow cylinders made of microtubules
• Microfilaments


  Contractile fibres formed from actin, responsible or cell movement and contraction during cytokinesis
• Microtubules


  Determine shape of cell and act as tracks for the movement of organelles
• Intermediate fibres


  Give cell mechanical strength and help maintain their integrity
• Vacuoles


  Membrane lined sacs containing cell sap. Important in maintenance of turgor.
• Tonoplast


  Membrane of vacuole and is selectively permeable
• DNA in prokaryotic cells


  Circular, proteins fold and condense DNA, one molecule, chromosome
• DNA in eukaryotic cells

  Linear, associated with proteins called histones forming chromatin, multiple chromosomes
• Cell wall in prokaryotic cells made from

  Peptidoglycan/murein
• Call wall in fungi made from

  Chitin
• Flagella in prokaryotic cells

  Made of flagellin, arranged in a helix
• Flagella in eukaryotic cells

  Made of microtubules, arranged 9+2 formation
• Importance of cytoskeleton


  Provide mechanical strength, aiding transport within cells, enabling movement
• High latent heat of evaporation


  Lot of energy used up when water evaporates - coolant
• Biuret test tests for?

  Proteins
• Biuret test method


  1. Add few drops of NaOH

  2. Add copper sulfate solution
• Positive result for biuret test

  blue to purple
• What does Benedict's test for

  reducing sugars (all monosaccharides, glucose, & some disaccharides, maltose & lactose)
• Method for benedicts test

  Add benedicts reagent and heat in water bath
• Positive result for benedicts test

  blue --> coloured ppt (brick red)
• Benedicts test for non-reducing sugars method

  break down into monosaccharide by adding dilute HCl & heating in water bath.

  Neutralise with sodiumhydrogencarbonate

  Carry out benedicts
• Non reducing sugar example

  sucrose
• Iodine test tests for?

  Starch
• Iodine test method


  Add iodine dissolved in KI solution
• Positive result for iodine test


  browny orange to dark blue-black
• Emulsion test tests for?

  Lipids
• Emulsion test method


  Shake test substance with ethanol for about a minute

  Poor solution into walk
• Positive result for emulsion test

  Solution turns milky
• Biosensors


  A device that used a biological molecule to select a chemical