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• What are the two types of cells?

  Prokaryotic and Eukaryotic
• what are the differences between eukaryotic and prokaryotic cells?

  prokaryotic cells are much smaller than eukaryotic cells

  eukaryotic cells contain membrane bound-organelles and a nucleus containing genetic material, while prokaryotes do not
• how is genetic information stored in a prokaryotic cell?

  chromosomal DNA

  Plasmid DNA
• What are plasmids?

  Plasmids are small loops of extra DNA that aren't part of the chromosome. Plasmids contain genes for things like drug resistance and can be passed between bacteria.
• What is order of magnitude?

  A power to the base 10 used to quantify and compare size.
• What is a centimeter?

  1x10^-2 metres
• What is a milimeter?


  1x10^-3 metres
• What is a micrometer?

  1x10^-6 metres
• What is a nanometer?

  1x10^-9 metres
• list the components of both plants and animals cells (5)

  nucleus, cytoplasm, cell membrane, mitochondria, ribosomes
• additional cell components found in plant cells?

  chloroplasts, permanent vacuole, cell wall
• function of nucleus

  Directs all the cells activities; contains the cells DNA
• Structure of Cytoplasm

  -semi-transparent gelatinous fluid

  -it contains enzymes, ribosomes, and organelles
• Function of cytoplasm

  Where chemical reactions take place
• Function of cell membrane

  regulates what enters and leaves the cell
• function of mitochondria

  Cellular respiration, makes ATP.
• function of ribosomes

  protein synthesis
• what is plant cell wall made of

  cellulose
• function of plant cell wall

  ● Provides strength.

  ● Prevents the cell bursting when water enters by osmosis.
• What does the permanent vacuole contain?

  Cell sap - a weak solution of sugar and salts.
• what is the function of the permanent vacuole?

  Supports the cell, maintaining its turgidity
• what is the function of chloroplasts?

  Site of photosynthesis
• how are sperm cells in animals adapted to their function?

  haploid nucleus contains genetic information

  tail enables movement

  mitochondria provides energy for tail movement
• how are nerve cells in animals adapted to their function

  long axon- allows electrical impulses to be transmitted

  myelin sheath- insulates the axon and speeds up transmission of impulses
• How are muscle cells specialised?

  They are long and contain a lot of mitochondria for contraction
• How are root hair cells specialised?

  Has a large surface area to absorb more water and mineral ions
• How are xylem cells specialised?

  They are hollow in the centre and have very few sub-cellular structures so that stuff can flow through them
• How are phloem cells specialised?

  Their end walls allow sugars through but support the tubes + phloem cells are arranged end to end into tubes + they have companion cells in-between them
• What is cell differentiation?

  The process in which cells become specialized.
• Why is cell differentiation important?

  Allows production of different tissues and organs that perform various vital functions in the human body.
• what is the main purpose of cell division in animals

  repair and replacement of cells
• Define magnification and resolution.

  Magnification: factor by which the image is larger than the actual specimen.

  Resolution: smallest separation distance at which 2 separate structures can be distinguished from one another.
• How does a light microscope work?

  Passes a beam of light through a specimen which travels through the eyepiece lens, allowing the specimen to be observed.
• Advantages of light microscope

  able to view living organisms, relatively inexpensive
• Disadvantage of light microscopes

  Cannot view tiny cell parts, molecules
• How does an electron microscope work?

  It uses a beam of electrons which are focused using magnets. The electrons hit a fluorescent screen which emits visible light, producing an image.
• Two types of electron microscopes

  transmission and scanning
• Advantage of electron microscope

  Greater magnification and resolution
• disadvantages of electron microscope

  Expensive to buy,

  Difficult to prepare,

  Large and stationary,

  Black and white, but false colour can be added in after,

  Specimens must be dead
• Magnification equation


  Image size/actual size