Biology - AQA 2025

• Metabolism is the sum of all the reactions in a cell or the body.
• Structures in order of size with the largest first:

  Liver cell, nucleus, bacterium, ribosome
• A nucleus is measured as 0.005 in diameter. How many micrometres is this?

  5 micrometres
• A student draws a cheek cell. The cell in their drawing is 50mm wide. In real life the cell is 0.025mm. What is the magnification of their drawing?

  2000 times
• What term in used to describe the ability to see two or more objects as separate objects?

  Resolution
• A tissue sample is added to a slide.

  What is the next step before lowering a coverslip onto the sample?

  Add a few drops of a suitable stain
• If the size of an image is 5cm in height and the size of the real object is 0.05mm, what is the magnification?


  x1000
• If the size of an image is 8.5cm and the magnification is x50, what is the size of the real object in mm?

  1.7mm
• What subcellular structure cannot be seen using a light microscope?

  Ribosome
• An animal cell is 20 micrometres in diameter.

  What is its size in cm?

  2.0x10^-3cm