1. Cells

• What three things do ALL cells contain

  A cell surface membrane

  cytoplasm

  genetic material
• Describe and give function of DNA in prokaryotes

  Describe - short circular DNA not associated with histone proteins

  function- carried genetic codes for protein
• Describe and give function of the cell wall of prokaryotic cells

  Describe- contains murein which is a glycoprotein

  function - rigid and strengthens
• Describe and give the function of cell membrane of prokaryotes

  Describe - phospholipid bilayer

  function - controls passage of substances
• Describe and give function of cytoplasm in prokaryotes and eukaryotes

  Describe- solution where many dissolved molecules are found

  function - site of metabolic reactions
• Describe and give function of ribosomes in prokaryotes

  Describe - small 70s

  function - protein synthesis
• Describe and give function of a flagellum on a prokaryote

  Describe - thin rotating fibre

  function - allows movement
• Describe and give function of plasmids in a prokaryote

  Describe - small loops of DNA that replicate independently

  function - pass on genetic info via conjugation with another cell
• Describe and give function of a capsule on a prokaryotic cell

  Describe - extra layer

  function - prevents desiccation and phagocytosis
• Give the function of a plasma membrane for eukaryotes

  Selectively permeable
• Describe and give function of nucleus in eukaryotes

  Describe - surrounded by a nuclear envelope containing pores. Has one or more nucleoli. Contains chromosomes - linear DNA

  function - genetic code
• Describe and give function for mitochondria in eukaryotes

  Describe - surrounded by two membranes fluid inside is called matrix and contains DNA

  function - site of aerobic respiration producing ATP
• Describe and give function of rough endoplasmic reticulum in eukaryotes

  Describe - long flat tubes containing ribosomes

  function - synthesis and transport of proteins
• Describe and give function of smooth endoplasmic reticulum in eukaryotes

  Describe - series of tubes with no ribosomes

  function - synthesis and transport of lipids
• Describe and give function of Golgi apparatus in eukaryotic cells

  Describe - flattened sacs that vesicles bud off

  function - modified and packaged protein
• What are lysosomes

  Small vesicles containing hydrolytic enzymes that digest broken or unwanted organelles.
• What is the difference between eukaryotic ribosomes and prokaryotic ribosomes

  Eukaryotic has larger (80s) ribosomes
• What three features are NOT always present in a prokaryotic cell

  Flagellum

  capsids

  capsule
• What three things do plant Cells have that animal cells don’t

  Vacuole

  chloroplasts

  cell wall
• What is the cell wall of a plant cell made of

  Cellulose. Prevents osmotic lysis
• What is the cell wall of fungi made of

  Chitin
• What is a granum in a chloroplast

  Stack of membrane bound discs called thylakoids. contain chlorophyll
• Define tissue

  A group of similar cells
• Define muscle

  Group of tissues
• Define organ system

  Group of interacting organs working together
• Why are viruses known as acellular

  They are non living so therefore are not cells
• Magnification can be defined as …

  Number of times bigger the image is than the actual object
• Resolution can be defined as…

  Minimum distance between two dots at which they can be seen as separate
• How do optical microscopes work

  Use light and glass lenses to focus the light

  specimen must also be thin
• Is resolution high or low in optical microscopes and why

  Low as light has a long wavelength
• How does an electron microscope work

  Beam of electrons which are focussed using electromagnets
• Why does electron microscope have much higher resolution

  Much smaller wavelength
• What are the two types of electron microscopes

  Scanning electron microscope (SEM)

  transmission electron microscopes (TEM)
• What are properties of scanning EM

  lower resolution

  can give 3D images

  surface of the object

  doesn’t require thin section
• Properties of transmission (EM)

  Higher resolution

  thin sections

  no 3D image

  internal details are shown
• which has a better magnification light or electron microscope

  Electron - up to 500,000

  light only 1500
• What is an artefact

  Something that results from the way a slide is prepared - air bubble or dust .
• How to convert mm to micro metres

  X1000
• Equation for magnification

  Image size = actual size x magnification
• How to estimate size of object

  Eye piece graticule is calibrated against the stage micrometer scale of known length. Can then be used.