Cell structure

You will be able to

• Explain the difference between magnification and resolution, and why a light microscope cannot resolve structures closer than about 200 nm however much it magnifies.
• Calculate the actual size of a structure or the magnification of an image, converting between mm, µm and nm.
• Describe how to make a temporary preparation and what makes a good biological drawing.

You will be able to

• Calibrate an eyepiece graticule against a stage micrometer and calculate the length of one eyepiece unit in µm.
• Explain why the graticule must be recalibrated for each objective lens.
• Calculate the actual length of a specimen from its length in eyepiece units.

You will be able to

• Describe the structure and function of each organelle and cell structure in typical animal and plant cells, including 80S and 70S ribosomes.
• Explain the route of a secreted protein through the rough ER, Golgi body and vesicles, and state that cells use ATP from respiration for energy-requiring processes.
• Identify structures in electron micrographs and compare the structure of typical plant and animal cells.

You will be able to

• Outline the structural features of a typical bacterium and compare it with typical animal and plant cells.
• State that viruses are non-cellular, with a nucleic acid core and a protein capsid, some with a phospholipid envelope, and explain why a virus cannot make proteins on its own.
• Classify an unknown specimen from evidence such as its size, ribosomes (70S or 80S), DNA and cell wall.