Question 19M.3.SL.TZ1.1a
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.3.SL.TZ1.1a |
| Level | SL | Paper | 3 | Time zone | TZ1 |
| Command term | Calculate | Question number | a | Adapted from | N/A |
Membrane structure can be investigated using a technique known as freeze fracture.
Cells are frozen and then split. Fracturing often occurs between the two phospholipid layers of membranes in the cell. An electron micrograph of such a fractured membrane is shown.
[Source: © Science Photo Library]
Using the scale bar, calculate the magnification of the image.
[2]
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Two marks were awarded for an answer within the given range, since many candidates did not show working, and the question did not request it. Many candidates measured the whole diagram for the numerator instead of the scale bar, and others inverted the formula. A formula in words that appeared correct was not credited if the numbers then negated this. Errors in unit conversion were frequent, but credit was given for working.
