- Specification route
- 3.4.7
- Question bank
- 27 questions
- Course stage
- AS / Year 12
Practise this topic
27 standard questions. No sign-in required.
Practise Biology maths and data skills
Sessions use up to the requested number of available questions. Standard practice uses levels 1–5.
Sample questions
Historically, genetic diversity was estimated by comparing the frequency of observable characteristics. What modern techniques are now used for more accurate comparisons?
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Modern technology allows us to look at the molecules that actually code for those observable characteristics.
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Answer: Comparing the base sequences of DNA or mRNA, and the amino acid sequences of proteins.
Genetic diversity within, or between species, can be made by comparing: the frequency of measurable or observable characteristics; the base sequence of DNA; the base sequence of mRNA; the amino acid sequence of the proteins.
When undertaking quantitative investigations of variation within a species, why is it essential to collect data from random samples?
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If you only measure the tallest plants, your average will not reflect the true population.
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Answer: To avoid bias and ensure the data accurately represents the whole population.
Quantitative investigations of variation within a species involve: collecting data from random samples. Random sampling avoids investigator bias.
Scientists discover two morphologically identical populations of frogs. They compare the sequence of amino acids in a specific respiratory protein. Why might this protein sequence be identical even if their DNA sequences are slightly different?
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Multiple 'words' in the DNA dictionary can translate to the same 'meaning' in a protein.
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Answer: Because the genetic code is degenerate; different DNA base triplets can code for the exact same amino acids.
Genetic diversity within, or between species, can be made by comparing... the base sequence of DNA... the amino acid sequence. Due to the degenerate nature of the genetic code, a silent mutation in DNA will not alter the amino acid sequence.
Two samples have means shown with error bars of $\pm 1$ standard deviation, and the error bars overlap. What can you conclude from this alone?
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Standard deviation describes spread. Statistical significance is a separate question.
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Answer: The error bars show that the data distributions have overlapping spread, but they do not by themselves determine whether the difference between the means is statistically significant.
Standard deviation describes how spread out observations are around a mean. The amount of overlap between SD bars can be a useful visual clue, but it is not a statistical significance test. Use an appropriate statistical test before deciding whether the difference is significant.
A researcher wants to investigate the variation in leaf length of a specific plant species in a field. How can they ensure their sample is truly random to avoid investigator bias?
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Human choice must be completely removed from the selection process.
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Answer: By laying out a grid using tape measures and using a random number generator to select coordinates for sampling.
Quantitative investigations of variation within a species involve: collecting data from random samples. Throwing quadrats is biased (humans influence the throw). Grid coordinates combined with random number generation is strictly objective.
Why is comparing the base sequence of mRNA often considered more useful than comparing observable characteristics when investigating genetic diversity?
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Looks can be deceiving due to external factors like diet or climate.
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Answer: Observable characteristics are often polygenic and highly influenced by the environment, whereas mRNA directly reflects the transcribed genetic code.
Comparing observable characteristics has limitations because many characteristics are polygenic (coded by multiple genes) and environmental factors can modify them. Direct DNA/mRNA sequencing provides an unambiguous, objective measure of genetic diversity.
Advances in immunology allow scientists to investigate evolutionary relationships. How is this achieved?
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Proteins have specific 3D shapes. Antibodies bind to specific shapes (antigens).
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Answer: By comparing the cross-reactivity of antibodies with proteins from different species to measure similarity.
Genetic diversity within, or between species, can be made by comparing... immunological comparisons of proteins. Antibodies specific to the proteins of one species will bind strongly to the highly similar proteins of a closely related species.
When investigating variation, why must data be collected from random samples?
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If a researcher chooses where to place a quadrat, they might subconsciously pick areas with more plants.
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Answer: To ensure the sample is representative of the whole population and to eliminate investigator bias.
Quantitative investigations of variation within a species involve: collecting data from random samples. This removes human bias and ensures mathematical reliability.
Practise this topic
27 standard questions are available (levels 1–5). No sign-in required.