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 8 of 17
- Q19 · 2021 QCAA · Paper 1 · 1 markGenetics and heredityQUESTION 19 What is the role of DNA polymerase in DNA replication? (A) breaking the hydrogen bonds that hold the complementary bases of DNA together (B) adding complementary nucleotide bases to the exposed DNA strands (C) sealing the sequence of DNA into two continuous double strands (D) joining RNA primers to the lagging strand of DNA
- Q20 · 2021 QCAA · Paper 1 · 1 markFunctioning ecosystems and successionQUESTION 20 A keystone species is defined as a species that (A) is the top predator in an ecosystem. (B) is a major producer in an ecosystem. (C) has a unique and crucial role in an ecosystem. (D) directly influences all species in an ecosystem. References Question 10 Adapted from OpenStax 2018, Figure 6 in ‘OpenStax Biology 2e’, Lumencandela, available…
- Q21 · 2021 QCAA · Paper 1 · 4 marksBiodiversity and populationsQUESTION 21 (4 marks) In the Linnaean system of classification, the features used to classify living things change according to taxonomic levels. Describe, using relevant examples, how these features change.
- Q22 · 2021 QCAA · Paper 1 · 3 marksFunctioning ecosystems and successionQUESTION 22 (3 marks) Describe two ways carbon is transformed and one way it is transferred as it cycles through the biotic components of an ecosystem.
- Q23 · 2021 QCAA · Paper 1 · 5 marksBiodiversity and populationsQUESTION 23 (5 marks) To determine the species diversity and species richness of a wetland ecosystem, ecologists surveyed communities adjacent to a river, using two methods for each community: 1. random species sampling with predetermined grid numbers, with 10 quadrats of 4 m2 each used for these grids 2. three belt transect lines (50 m × 2 m) across pred…
- Q24 · 2021 QCAA · Paper 1 · 5 marksFunctioning ecosystems and successionQUESTION 24 (5 marks) The diagram is a hypothetical biomass pyramid for a community. Secondary consumers 76 kg Primary consumers 1520 kg Producers 15 200 kg Not to scale a) Contrast the efficiency of the biomass transfers between each level of the pyramid. [3 marks] b) Explain the difference in biomass transfer efficiency identified in Question 24a). [2 m…
- Q25 · 2021 QCAA · Paper 1 · 3 marksGenetics and heredityQUESTION 25 (3 marks) In blood group inheritance in humans, three alleles (i, IA and IB) determine blood type, which can be type O, A, B or AB. It is known that: • allele IA produces type A and is co-dominant with allele IB, which produces type B • allele i produces type O • alleles IA and IB are dominant over allele i. A father who is heterozygous type…
- Q26 · 2021 QCAA · Paper 1 · 4 marksGenetics and heredityQUESTION 26 (4 marks) a) State the three components of a DNA nucleotide. [1 mark] b) Describe the steps involved in DNA profiling. [3 marks]
- Q27 · 2021 QCAA · Paper 1 · 3 marksContinuity of life on EarthQUESTION 27 (3 marks) The table shows the percentage sequence similarity for three different parts of a gene found in four different eukaryotic species. The data was obtained by comparing DNA from one member of each species to Species A. From this data, a proposed phylogenetic tree was produced. Species Gene region 1 Gene region 2 Gene region 3 A 100% 100%…
- Q28 · 2021 QCAA · Paper 1 · 3 marksBiodiversity and populationsQUESTION 28 (3 marks) The graph depicts the population change of a species after it is introduced into a previously disturbed environment. Phase B Population size Phase A Time Referring to Phase A and Phase B, determine the population growth model for the species.
- Q1 · 2021 QCAA · Paper 2 · 4 marksBiodiversity and populationsQUESTION 1 (4 marks) Explain how one abiotic and one biotic factor will affect the population of mosquito larvae in a freshwater pond.
- Q2 · 2021 QCAA · Paper 2 · 3 marksGenetics and heredityQUESTION 2 (3 marks) a) Explain the difference between exons and introns. [2 marks] b) State a function of telomeres. [1 mark]
- Q3 · 2021 QCAA · Paper 2 · 3 marksFunctioning ecosystems and successionQUESTION 3 (3 marks) In coastal areas and deserts, bare sand dunes may be colonised by plants such as members of the Poaceae family (grasses). Identify three features of these plants that make them effective colonisers.
- Q4 · 2021 QCAA · Paper 2 · 2 marksGenetics and heredityQUESTION 4 (2 marks) Explain the purpose of the polymerase chain reaction (PCR) process and provide an example of its application.
- Q5 · 2021 QCAA · Paper 2 · 6 marksGenetics and heredityQUESTION 5 (6 marks) Meiosis ensures that a wide range of genetic combinations occurs during the formation of gametes. The diagrams show two processes that occur during meiosis. Process 1 a a A A A a A a A b b B B b b B B Duplicated homologous chromosomes Process 2 Duplicated chromosomes Membrane Describe the two processes shown in the diagrams and how they…
- Q6 · 2021 QCAA · Paper 2 · 2 marksBiodiversity and populationsQUESTION 6 (2 marks) The term species could be defined as ‘one group of individuals that actually or potentially interbreed in nature’. Identify two limitations of this definition.
- Q7 · 2021 QCAA · Paper 2 · 3 marksContinuity of life on EarthQUESTION 7 (3 marks) Koalas were once widespread in Australia. Due to a variety of factors, their population decreased and fragmented into small pockets, forcing them to inbreed. They have recently been hit by devastating epidemic diseases. Explain why koalas face an increased extinction risk from disease.
- Q8 · 2021 QCAA · Paper 2 · 3 marksContinuity of life on EarthQUESTION 8 (3 marks) Australia has many bird species that have evolved to be largely dependent on mangroves. These species are patchy in their distribution because of: • the island-like distribution of their habitat • exclusion by possible competitors • geographical barriers. Identify and describe the mode of speciation that may have caused diversity in…
- Q9 · 2021 QCAA · Paper 2 · 3 marksContinuity of life on EarthQUESTION 9 (3 marks) A computer simulation was used to observe genotypic changes in the gene pool of 20 randomly selected rabbits. The simulation was set with these parameters: • each rabbit’s coat colour was either black or white • black alleles were dominant; white alleles were recessive • the number of rabbits was constant in each generation and breed…
- Q10 · 2021 QCAA · Paper 2 · 3 marksGenetics and heredityQUESTION 10 (3 marks) Describe three ways DNA occurs in cells.
- Q11 · 2021 QCAA · Paper 2 · 2 marksGenetics and heredityQUESTION 11 (2 marks) Adult skeletal stem cells differentiate into intermediate cells and later into specialised bone tissue types. Skeletal stem cell Intermediate cell Spongy bone Cartilage Compact bone The table shows how three transcription factors (A, B and C) affect bone tissue formation. Transcription Intermediate cell Cartilage Compact bone factor ro…
- Q12 · 2021 QCAA · Paper 2 · 5 marksBiodiversity and populationsQUESTION 12 (5 marks) An investigation compared mangrove species diversity for two areas of different size in the same catchment. The table shows species population counts for each area. Area 1 Area 2 Grey mangrove 37 7 Total Red mangrove 32 3 species count Yellow mangrove 25 88 SDI 0.67 ? a) Calculate Simpson’s diversity index for Area 2. Show your workin…
- Q13 · 2021 QCAA · Paper 2 · 3 marksFunctioning ecosystems and successionQUESTION 13 (3 marks) The data shows changes in relative abundance of ground cover, biomass and species diversity for an abandoned sand mine site over time. Key Bare ground Grasses Abundance (e.g. spinifex, tussock grass) Seedlings/shrubs (e.g. banksia, eucalypt) Leaf litter Mature trees Time Key Biomass Biomass (kg/m2) Species diversity Time Based on the i…
- Q1 · 2020 QCAA · Paper 1 · 1 markGenetics and heredityQUESTION 1 In prokaryotes, deoxyribonucleic acid (DNA) is found as unbound circular DNA in the (A) mitochondria. (B) chloroplasts. (C) nucleus. (D) cytosol.