| Date | November 2015 | Marks available | 1 | Reference code | 15N.2.SL.TZ0.2 |
| Level | Standard level | Paper | Paper 2 | Time zone | TZ0 |
| Command term | Define | Question number | 2 | Adapted from | N/A |
Question
The diagrams show a virus and a bacterium.
Calculate the magnification of the bacterium.
State the method that bacteria use to divide.
Outline the effectiveness of antibiotics against viruses and bacteria.
Saprotrophic organisms, such as Mucor species, are abundant in soils.
Define saprotrophic organisms.
State one role of saprotrophic organisms in the ecosystem.
Markscheme
45 000(x) or (x)45000 (accept answers in the range of 44000 to 46 000)
binary fission
effective against bacteria, but not viruses
an organism that secretes enzymes in dead organic matter and absorbs its nutrients/products of digestion
decomposer / recycle nutrients / break down organic material into inorganic material
Do not just accept "recycle" alone.
Examiners report
Once again a simple calculation resulted in answers that were both incorrect and illogical. Better candidates gained the mark for 45000x. Some lost the mark for incorrect units.
‘Binary fusion’ was the most common wrong answer.
Most knew that antibiotics are effective against bacteria, not viruses. An explanation was not required.
These were really definitions from the syllabus.
These were really definitions from the syllabus.
