Biology questions and solutions
Browse original practice and official past-paper questions. Each question has its own link, with its source and worked solution.
385 questions · Page 4 of 17
- Q9 · 2024 QCAA · Paper 2 · 10 marksGenetics and heredityQUESTION 9 (10 marks) The diagram shows key stages of gene expression. I III IV II a) Identify structures I, II and III. [3 marks] I: II: III: b) Describe the role of structure IV and explain how it carries out this function. [3 marks] c) Describe two ways gene expression is regulated. [2 marks] d) Explain two reasons why genetic mutations do not always…
- Q10 · 2024 QCAA · Paper 2 · 5 marksContinuity of life on EarthQUESTION 10 (5 marks) The chart shows the number of families in nine classes of vertebrate (A to I) over geological time. Class of vertebrate A B E F G H I Era Cenozoic Mesozoic Time D C Paleozoic Scale: 60 families a) Identify a trend in vertebrate biodiversity over time. Refer to data to support your response. [2 marks] b) Identify which classes became…
- Q11 · 2024 QCAA · Paper 2 · 4 marksFunctioning ecosystems and successionQUESTION 11 (4 marks) a) Describe the process of ecological succession. [3 marks] b) Distinguish between primary and secondary succession. [1 mark]
- Q1 · 2023 QCAA · Paper 1 · 1 markBiodiversity and populationsQUESTION 1 The biological species concept defines species as a group of organisms (A) with a common set of alleles. (B) descended from a common ancestor. (C) occupying the same niche or adaptive zone. (D) that can interbreed to produce fertile offspring.
- Q2 · 2023 QCAA · Paper 1 · 1 markBiodiversity and populationsQUESTION 2 Species classified as K-strategists (A) often live in unstable habitats. (B) exhibit an exponential rate of reproduction. (C) reach sexual maturity later than r-strategists. (D) are first to colonise a new environment created by a disturbance.
- Q3 · 2023 QCAA · Paper 1 · 1 markBiodiversity and populationsQUESTION 3 The table provides population data for a species of fairy-wren. Year Population on Births Deaths Immigration Emigration 1st January 2022 15 200 7600 4310 790 24 The population growth rate in 2022 was closest to (A) 17% (B) 27% (C) 55% (D) 73%
- Q4 · 2023 QCAA · Paper 1 · 1 markContinuity of life on EarthQUESTION 4 Populations with reduced genetic diversity face an increased risk of extinction because they (A) have fewer chromosomes. (B) have difficulty finding mates for reproduction. (C) are less likely to adapt to changing environments. (D) contain a larger proportion of heterozygous individuals.
- Q5 · 2023 QCAA · Paper 1 · 1 markGenetics and heredityQUESTION 5 Which statement is true for DNA replication? (A) Adenine pairs with guanine. (B) The process occurs during metaphase I. (C) DNA polymerase unwinds the double helix. (D) New strands are synthesised in the 5’ to 3’ direction.
- Q6 · 2023 QCAA · Paper 1 · 1 markContinuity of life on EarthThe reconstructed phylogenetic tree shows evolutionary relationships between eight Himalayan songbirds and the elevations they inhabit. The data shows that
- Q7 · 2023 QCAA · Paper 1 · 1 markContinuity of life on EarthQUESTION 7 The distributions of phenotypes before and after a selection pressure acted on a population are shown. Which graph shows disruptive selection? Key ciate Before selection pressure 25 generations later a 2 Zh (A) ‘gs (B) ‘gs a=] a=] z 2 3 3 & & ml e o S - - 3 3 — — = i] Zz Zz Phenotype an © 2 ©) = = vc 2 vos = 2 yoo 3 ao) / =| a ’ oe Ge / iS) lo} 1…
- Q8 · 2023 QCAA · Paper 1 · 1 markGenetics and heredityQUESTION 8 The diagram shows a human karyotype and a list of genetic conditions. Hon 4 ee ee ee 3 Goes okt fg Genetic condition Common name Monosomy X Turner syndrome Monosomy 5 Cri du chat syndrome Trisomy 18 Edwards syndrome Trisomy 21 Down syndrome Which genetic condition is indicated in the karyotype? (A) Turner syndrome (B) Cri du chat syndrome (C) Edwa…
- Q9 · 2023 QCAA · Paper 1 · 1 markFunctioning ecosystems and successionQUESTION 9 An ecological niche refers to (A) a group of organisms competing for the same resources. (B) the role and space that an organism fills in an ecosystem. (C) all organisms occupying a physical space close enough to interact with each other. (D) the largest population of a particular species that can be supported by an ecosystem.
- Q10 · 2023 QCAA · Paper 1 · 1 markContinuity of life on EarthQUESTION 10 The graph shows extinction rates over time. ee FP eB WN YN fF De OS Extinction rate (families per million years) n l f 1 ] = _ aa i) T T T T T T T T 500 450 400 350 300 250 200 150 100 50 0 Millions of years ago (Mya) How many times in the past 500 million years has the extinction rate exceeded 14 families per million years? (A) 3 (B) 4 (C) 5 (D)…
- Q11 · 2023 QCAA · Paper 1 · 1 markGenetics and heredityQUESTION 11 Restriction enzymes (A) join DNA into a single strand. (B) cut DNA at specific locations. (C) add nucleotides to a growing DNA strand. (D) assist in the amplification of recombinant DNA.
- Q12 · 2023 QCAA · Paper 1 · 1 markBiodiversity and populationsQUESTION 12 The graph shows the results of a study on the species richness of gut microbes. The data represents the cumulative number of species observed as the number of samples increased. 800 700 600. Number of species 500 400 300 200 100 Number of samples Based on this data, the minimum number of samples required to obtain valid species richness data is (…
- Q13 · 2023 QCAA · Paper 1 · 1 markContinuity of life on EarthQUESTION 13 Which option best describes the conditions for parapatric speciation? (A) Geographical barriers limit gene flow between populations. (B) Gene flow is interrupted in populations occupying the same habitat. (C) Aspecies occupies such a large geographical area that mate selection is influenced by proximity. (D) Asmall group of organisms becomes sepa…
- Q14 · 2023 QCAA · Paper 1 · 1 markFunctioning ecosystems and successionQUESTION 14 An energy pyramid for an aquatic ecosystem is shown (values are in kJ m~ y). Not to scale tertiary consumers 20 secondary consumers 410 primary consumers 3400 producers 21 600 Transfer efficiency between producers and primary consumers is closest to (A) 5% (B) 10% (C) 12% (D) 16%
- Q15 · 2023 QCAA · Paper 1 · 1 markContinuity of life on EarthQUESTION 15 Allele frequencies are most likely to stay constant in (A) large populations with low levels of migration. (B) small populations with low levels of migration. (C) large populations with high levels of migration. (D) small populations with high levels of migration.
- Q16 · 2023 QCAA · Paper 1 · 1 markGenetics and heredityQUESTION 16 The diagram shows a section of DNA. DNA Key Introns 1 Exons Immediately following transcription and RNA splicing, the product would most closely resemble (A) mRNA: GSS (B) RNA Ss (C) mRNA: (D) tRNA:
- Q17 · 2023 QCAA · Paper 1 · 1 markGenetics and heredityQUESTION 17 What is the most likely outcome of a homeobox (HOX) gene mutation? (A) slower growth rate (B) body appendages in the incorrect location (C) failure of sex characteristics to fully develop (D) impaired ability of red blood cells to carry oxygen
- Q18 · 2023 QCAA · Paper 1 · 1 markGenetics and heredityQUESTION 18 Calcium chloride (CaCl,) is a chemical used in bacterial transformation. An experiment was conducted to determine how the concentration of calcium chloride affects the transformation efficiency of large and small plasmids. Error bars show standard error. Transformation efficiency (04 cfu/ug) Key — Small plasmids cara Large plasmids 0.0 0.1 0.2 0.…
- Q19 · 2023 QCAA · Paper 1 · 1 markGenetics and heredityQUESTION 19 Electrophoresis separates DNA fragments based on (A) size, with larger fragments travelling further through the gel. (B) size, with smaller fragments travelling further through the gel. (C) charge, with more positively charged fragments travelling further through the gel. (D) charge, with more negatively charged fragments travelling further throu…
- Q20 · 2023 QCAA · Paper 1 · 1 markBiodiversity and populationsQUESTION 20 Mxn The capture—recapture method and Lincoln index (N = ) were used to monitor a population of m platypuses over a four-year period. Experimental findings are shown. 26 24 22 20 Number of platypuses 18 16 14 12 10 oN FRO WO 2019 2020 2021 2022 Year The table shows data from one year of the study. Number of individuals captured and marked in first…
- Q21 · 2023 QCAA · Paper 1 · 4 marksGenetics and heredityThe diagram represents a section of DNA. Identify the DNA components indicated by labels 1–4.