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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 2 of 5

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

1Cells & microscopyA diploid parent cell has 8 chromosomes. In the standard mitosis model, how many chromosomes does each daughter nucleus receive?
2Cells & microscopyWhich structure does a typical bacterial cell have: the cell membrane or the nucleus?
3Human biology & physiologyA fictional circulation model has 73 beats/min and 62 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 statement is accurate?
5Genetics & inheritanceIn pea plants, the allele for round seeds (R) is dominant over the allele for wrinkled seeds (r). Two plants, RR × rr, are crossed. What percentage of the offspring are expected to have the genotype rr?
%
6Genetics & inheritanceA fictional diploid organism has 68 chromosomes in a normal somatic nucleus. In the standard meiosis model, how many chromosomes are in a haploid gamete? Round to 3 decimal places if needed.
7Genetics & inheritanceIn the simple Aa × Aa inheritance model with independent outcomes, the probability of aa is 1/4. Among 372 offspring, find the expected aa count, not a guaranteed outcome. Round to 3 decimal places if needed.
8Ecology & populationsSupplied fictional records give M = 99 initially marked, C = 68 in a later sample, and R = 53 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.
9Ecology & populationsA fictional population starts at 409. During one interval: 72 births, 12 arrivals, 44 deaths and 10 departures. Find the final count. Round to 3 decimal places if needed.
10Ecology & populationsIn this simplified food chain: grass → mouse → snake → owl. At which trophic level is “owl”? (Producers are level 1.)
11Measurement & evidenceInvestigation: Identical bean plants are grown under lamps of different brightness, each given the same volume of water, and their heights are measured after three weeks. In this investigation, which is a controlled 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 64 plants in 7 non-overlapping quadrats, each 0.25 m². Find the mean density in the sampled area. Round to 3 decimal places if needed. Answer in plants/m².
plants/m²
14Human biology & physiology (Grade 11)What defines an artery?
15Cells & microscopy (Grade 11)Supplied plant-tissue data show initial mass 3.1 g and final mass 3.6 g. Find signed percentage mass change. No experiment is required. Round to 3 decimal places if needed. Answer in %.
%