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 5 of 17
- Q22 · 2023 QCAA · Paper 1 · 2 marksFunctioning ecosystems and successionQUESTION 22 (2 marks) Describe two ways bacteria assist matter to cycle through ecosystems.
- Q23 · 2023 QCAA · Paper 1 · 3 marksFunctioning ecosystems and successionQUESTION 23 (3 marks) Mistletoe is the common name for plants that have a close and long-term interaction with a host tree. In Australia, mistletoe frequently live on eucalyptus trees, penetrating the bark with their modified root systems to access water and nutrients from the xylem. This can restrict nutrient flow in the host tree and may cause parts of its…
- Q24 · 2023 QCAA · Paper 1 · 5 marksContinuity of life on EarthQUESTION 24 (5 marks) The frequency of a new allele was monitored in a population of insects over an 18-year period. 1.0 0.9 0.8 0.7 0.6 [ Frequency 0.5 0.4 l 0.3 0.2 | 0.1 0.0 2004 2006 2008 2010 2012 2014 2016 2018 2020 2022 Year a) Infer if the new allele is advantageous or detrimental in this environment. Justify your response using evidence from the gra…
- Q25 · 2023 QCAA · Paper 1 · 6 marksBiodiversity and populationsQUESTION 25 (6 marks) The effect of an invasive species on plant biodiversity was investigated by collecting this data from an ecosystem. Percentage cover (invasive species) 0-20% >20-40% | >40-60% | >60-80% >80-100% Species 7 7 7 4 biodiversity richness Plant Simpson’s 0.30 diversity index a) Contrast species richness in areas of low invasive species cover…
- Q26 · 2023 QCAA · Paper 1 · 3 marksFunctioning ecosystems and successionQUESTION 26 (3 marks) Wedge-tailed eagles are large birds that reside in tall trees, where they build nests for their young. They often feed on ground-dwelling herbivores such as kangaroos and rabbits. The graph shows the number of wedge-tailed eagles observed in an ecosystem over time. 800 : no} — of \ —_|— 600} 7 1 1 Sf g 500 ji fT 5 400 2 — 300 2 200 | 10…
- Q27 · 2023 QCAA · Paper 1 · 3 marksGenetics and heredityQUESTION 27 (3 marks) Clownfish have 24 pairs of chromosomes and reproduce via external fertilisation, with gametes initially created through meiosis. Females lay up to 1500 eggs and then males swim over the eggs and fertilise them. Explain how the processes of independent assortment and random fertilisation create variation in the genotypes of clownfish off…
- Q1 · 2023 QCAA · Paper 2 · 6 marksBiodiversity and populationsQUESTION 1 (6 marks) The profile diagram shows a representative section of an ecosystem. BO Height (m) iS) £ nt Distance (m) This table can be used to classify ecosystems based on Specht’s classification system. Foliage cover of tallest plant layer Life form and height Sparse (10-30%) of tallest stratum Trees >30 m Tall closed-forest Tall open-forest Tall wo…
- Q2 · 2023 QCAA · Paper 2 · 4 marksFunctioning ecosystems and successionThe reconstructed diagram shows feeding relationships for an Australian ecosystem.
- Q3 · 2023 QCAA · Paper 2 · 7 marksGenetics and heredityQUESTION 3 (7 marks) The chart shows the inheritance pattern of a trait, which is thought to be sex-linked dominant. | ad 1 2 omene 3 4 5 6 7 een enes 8 9 10 11 12 #13 ~ «14 Key HB Male with the trait ©) Parents @ Female with the trait O Offspring Male without the trait 1-16 used to identify each individual © Female without the trait a) Identify how many off…
- Q4 · 2023 QCAA · Paper 2 · 5 marksContinuity of life on EarthQUESTION 4 (5 marks) The hummingbird hawkmoth (phylum: Arthropoda) is named for its similarity to hummingbirds (phylum: Chordata). The two species have independently developed similar feeding structures, which they use to draw nectar from tube-shaped flowers. Both species help plants reproduce by distributing their pollen. Hummingbird hawkmoth Hummingbird Pr…
- Q5 · 2023 QCAA · Paper 2 · 3 marksContinuity of life on EarthQUESTION 5 (3 marks) Nucleic acid sequences were used to investigate evolutionary relationships between four species. Species Nucleic acid sequence B. bartonus GACCGCATTTACGTA B. deakinii GACGTCATATCCGTA B. reidus GACCGCATTTCCGTA B. watsonii GACGGCATATCCGTA a) Explain how data from conserved molecular sequences can be used to estimate time since divergence.…
- Q6 · 2023 QCAA · Paper 2 · 3 marksGenetics and heredityQUESTION 6 (3 marks) Explain how twin studies can be used to investigate the effect of the environment on gene expression.
- Q7 · 2023 QCAA · Paper 2 · 5 marksFunctioning ecosystems and successionQUESTION 7 (5 marks) The diagram shows the stages of succession in an ecosystem. Stage 1 Stage 2 Stage 3 Stage 4 Bare rock Lichen and Trees and shrubs Mature forest herbaceous plants |S. @.... 7 > Time a) Identify the type of ecological succession depicted. Explain your reasoning. [2 marks] b) Infer two features of the species in stage 2 and describe the rol…
- Q8 · 2023 QCAA · Paper 2 · 3 marksContinuity of life on EarthQUESTION 8 (3 marks) Explain how temporal isolation can lead to speciation.
- Q9 · 2023 QCAA · Paper 2 · 7 marksFunctioning ecosystems and successionQUESTION 9 (7 marks) The graphs show the findings of an experiment investigating the competitive exclusion principle. Two species of protozoa (P. aurelia and P. caudatum) were grown separately and together under identical conditions. Grown separately Grown together > 300 > 300 a SS Man & 250 2 8 7 g lia = 200 ot 2 2 B Bi 7 mo} S S & I ee nee ee ee 3 S = —] S…
- Q1 · 2022 QCAA · Paper 1 · 1 markGenetics and heredityQUESTION 1 What is the molecular unit of heredity? (A) gene (B) genome (C) nucleotide (D) chromosome
- Q2 · 2022 QCAA · Paper 1 · 1 markGenetics and heredityQUESTION 2 Which stage of making recombinant DNA requires DNA ligase? (A) cutting (B) joining (C) isolation (D) transformation
- Q3 · 2022 QCAA · Paper 1 · 1 markBiodiversity and populationsQUESTION 3 A survey of grasshopper species was conducted across four eucalypt communities. Counts were conducted and the average abundance per 400 m2 recorded. Grasshopper species (A–F) Community A B C D E F Total I 32 18 1 3 0 46 100 II 3 2 0 1 3 12 21 III 3 2 28 3 18 51 105 IV 18 13 12 14 16 15 88 Which community has both the highest species richness and h…
- Q4 · 2022 QCAA · Paper 1 · 1 markContinuity of life on EarthQUESTION 4 The graph shows the effect of a selection pressure on a hypothetical population. Key Before the selection pressure Number of individuals 20 generations later Phenotype Which mode of phenotypic selection corresponds with the data? (A) negative (B) disruptive (C) stabilising (D) directional
- Q5 · 2022 QCAA · Paper 1 · 1 markBiodiversity and populationsQUESTION 5 A researcher captured, marked and released 36 frogs. The following day they captured 24 frogs and 18 were marked. M n × Calculate the approximate size of the frog population using the Lincoln index: N = m (A) 27 (B) 48 (C) 54 (D) 60
- Q6 · 2022 QCAA · Paper 1 · 1 markGenetics and heredityQUESTION 6 The role of helicase in DNA replication is to (A) initiate the process by binding to recognition sites along the template strand. (B) add complementary bases to the template strand. (C) unwind and separate DNA strands. (D) join DNA strands together.
- Q7 · 2022 QCAA · Paper 1 · 1 markFunctioning ecosystems and successionQUESTION 7 What is used directly by plants for protein synthesis? – (A) nitrite, NO2 – (B) nitrate, NO3 (C) ammonia, NH3 (D) atmospheric nitrogen, N2
- Q8 · 2022 QCAA · Paper 1 · 1 markFunctioning ecosystems and successionQUESTION 8 The graph shows how the populations of two species in an ecosystem change over time. Key Species X Species Y Number of organisms Time Which species interaction is represented? (A) predation, where species X preys on species Y (B) predation, where species Y preys on species X (C) competition, where species X outcompetes species Y (D) competition, w…
- Q9 · 2022 QCAA · Paper 1 · 1 markGenetics and heredityQUESTION 9 Polygenic inheritance involves multiple (A) alleles for a single gene. (B) genes with the same alleles. (C) genes coding for a single characteristic. (D) characteristics resulting from a single gene.