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Grade 12 · Biology

Grade 12 Biology diagnostic

15 questions on cells & microscopy, human biology & physiology, genetics & inheritance, ecology & populations and measurement & evidence, plus 3 from Grade 11. Answer what you can, then check your answers to see which topics are secure and what to practise next.

15 questions5 topicsAbout 15 minutesSet 1 of 5

Skip a question if you do not know the answer. It is better than guessing, because it shows what to practise.

1Cells & microscopyWhich structure is found in plant cells but not in animal cells: the mitochondrion or the chloroplast?
2Cells & microscopyStarting with one cell, two complete rounds of division produce how many cells if none die?
3Human biology & physiologyA fictional circulation model has 75 beats/min and 79 mL/beat. Find its flow in mL/min. These are supplied model values, not diagnostic ranges. Round to 3 decimal places if needed. Answer in mL/min.
mL/min
4Human biology & physiologyWhich is an example of a physical barrier in innate defense?
5Genetics & inheritanceA DNA template strand reads TTGCGA. Which mRNA sequence is transcribed from it, read base by base in the same order?
6Genetics & inheritanceIn the simple Aa × Aa inheritance model with independent outcomes, the probability of aa is 1/4. Among 672 offspring, find the expected aa count, not a guaranteed outcome. Round to 3 decimal places if needed.
7Genetics & inheritanceIn pea plants, the allele for purple flowers (P) is dominant over the allele for white flowers (p). Two plants, PP × pp, are crossed. What percentage of the offspring are expected to have the genotype pp?
%
8Ecology & populationsA fictional population starts at 195. During one interval: 44 births, 12 arrivals, 24 deaths and 9 departures. Find the final count. Round to 3 decimal places if needed.
9Ecology & populationsSupplied fictional records give M = 60 initially marked, C = 82 in a later sample, and R = 19 marked in that sample. Use N ≈ MC/R under the stated assumptions. No animals are to be handled. Round to 3 decimal places if needed.
10Ecology & populationsIn this simplified food chain: phytoplankton → krill → baleen whale. If the population of “baleen whale” suddenly drops, what is the most likely short-term effect on the population of “krill”?
11Measurement & evidenceInvestigation: Radish seeds are placed on paper towels soaked in water with different salt concentrations, 20 seeds per dish, and the percentage that germinate is recorded. In this investigation, which is the independent variable?
12Measurement & evidenceWhich is the measured dependent variable in a stated light-versus-plant-height study?

From Grade 11

These questions check skills from the grade below, so gaps can be spotted early.

13Ecology & populations (Grade 11)A supplied survey counts 162 plants in 9 non-overlapping quadrats, each 0.5 m². Find the mean density in the sampled area. Round to 3 decimal places if needed. Answer in plants/m².
plants/m²
14Evolution & biodiversity (Grade 11)A survey lists 4 plant species, 3 insect species and 2 bird species, with no duplicates. How many species are listed?
15Genetics & inheritance (Grade 11)Which describes antiparallel strands?