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QUESTION 1 In prokaryotes deoxyribonucleic acid (DNA) is found as unbound circular DNA in the (A) mitochondria. (B) chloroplasts. (C) nucleus. (D) cytosol.
QUESTION 2 Which form of inheritance usually determines traits that display continuous phenotypic variation? (A) polygenic (B) sex-linked (C) multiple allele (D) incomplete dominance
QUESTION 3 A genome is defined as (A) the molecular unit of heredity. (B) all the genetic material in the chromosomes of an organism. (C) the sequence of triplets of DNA nucleotides that make up a gene. (D) the combination of alleles for a particular trait carried by an individual.
QUESTION 5 The figure shows the diversity of marine animals since the late Precambrian time. The data is from marine animal families that have been reliably preserved in the fossil record. 19OOT families 900 living 800 today 700 600 500 400 300 200 100 Number of marine families o Triassic - Jurassic Cretaceous Paleogene Neogene Ordovician Silurian Devonian Carboniferous Precambrian Cambrian p— S ) S 600 200 W S O N S S Millions of years ago Which of the following time periods saw the greatest evolutionary radiation of the marine families? (A) Ordovician (B) Cretaceous (C) Devonian (D) Permian
QUESTION 10 DNA profiling using polymerase chain reaction (PCR) and gel electrophoresis allows the comparison of (A) genes. (B) entire genomes. (C) DNA fragments. (D) specific sites of mutations.
QUESTION 12 In the structure of DNA adenine pairs with which other base? (A) wuracil (B) guanine (C) cytosine (D) thymine
QUESTION 13 Which of the following molecules is involved in the transcription of DNA? (A) RNA polymerase (B) DNA helicase (C) transfer RNA (D) amino acids
QUESTION 15 In watermelon skin colour is controlled by a single autosomal gene. The two phenotypic variants are green and striped. Two plants one homozygous for the green alleles and one homozygous for the striped alleles were crossed. The figure shows the phenotypic frequency for the initial (F ) generation and the subsequent (F ) generation. Frequency 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 Key I:’ green striped Fy F| Generation A cross was then performed between members of the F| generation. What would be the expected frequency of striped watermelon in the next (F ) generation? A) 1.0 (B) 075 (C) 0.50 (D) 0.25
QUESTION 17 The table identifies the condition associated with a variety of ploidy changes. Chromosome number ploidy Monosomy 5 Cri du chat syndrome Trisomy 23 Klinefelter syndrome For a person with XXY sex chromosomes which condition would they have? (A) Cri du chat syndrome (B) Down syndrome (C) Klinefelter syndrome (D) Turner syndrome
QUESTION 18 The diagram shows the abundance (n) of phenotypic and genotypic variation for the colour trait of a species of butterfly. AA Aa aa n =400 n =500 n= 1000 If these butterflies were placed in an environment with light-coloured trees which option from the table would be the most likely effect on the allelic frequencies? Frequency of allele/genotype A | 2 | AA | I = -- -- --
QUESTION 20 Which of the following are features of both microevolution and macroevolution? (A) mutations only (B) mutations and gene flow only (C) gene flow and genetic drift only (D) mutations gene flow and genetic drift
QUESTION 24 (3 marks) a) Describe what is meant by the genotype of an organism. [1 mark] b) Inherited mutations can affect the genotype of offspring. Describe how this occurs. [2 marks]
QUESTION 26 (1 mark) Define microevolution.
QUESTION 27 (4 marks) In a freshwater lake in Africa a species of crab and its snail prey species both exhibit specialisations that are unusual for freshwater species. The crabs possess strong claws with characteristics of marine crabs that crush and peel shells and the snail prey have thick strong shells that resist crushing. a) Identify which pattern of evolution this example represents. [1 mark] b) Describe how the two species may have evolved these characteristics. [3 marks]
QUESTION 3 (4 marks) Explain the role of the enzymes helicase and DNA polymerase in the process of DNA replication.
QUESTION 5 (4 marks) Explain the process of protein synthesis in terms of transcription and translation.
QUESTION 9 (3 marks) Fossil evidence seems to show that the morphology of the Queensland lung fish has remained relatively unchanged for the past 100 million years. Describe the features of the theory of natural selection to explain how this may have occurred.
QUESTION 10 (3 marks) Researchers measured the adult beak lengths of an entire population of a species of bird and plotted their results on the graph. After many generations the lengths of the adult beaks were again measured. By comparing this new data to the original data the researchers concluded that the average length of beaks had increased as a result of directional selection. nitial distribution / of beak lengths Frequency 0 5 10 15 20 Beak length (mm) a) Describe directional selection. [2 marks]
QUESTION 11 (6 marks) The image shows changes in the frequency of a particular gene in a single species of bird leading to a speciation event. These changes have occurred over a period of successive time points (i.e. I IT and III) each separated by approximately 1000 generations. » The letters A B C and D represent separate niches inhabited by the birds. * The arrows depict gene flow between the niches. » The allelic frequency for the gene is shown as f in each niche. 1 111 Draw a conclusion about the type of speciation that has occurred in this population. Explain your reasoning by referring to the information provided in each of the time points.
QUESTION 1 In mammals inherited mutations can cause variations in the genotype of offspring when they occur in (A) red blood cells. (B) somatic cells. (C) nerve cells. (D) sex cells.
QUESTION 4 To demonstrate polygenic inheritance of colour in wheat a cross was performed between two intermediate parents (AaBbCc X AaBbCc). Each dominant allele adds a “unit’ of colour to the phenotype. Which graph would depict the number of individuals and number of phenotypes for the cross? A 2 B) =z = 3 2 2 3 3 g g G~ G~ S o 3 z 2 2 Z Z 1 2 3 4 5 6 7 1 2 3 4 5 6 Number of phenotypes for colour Number of phenotypes for colour © = D) = - 5 = 2 3 3 g g = G~ S S 3 3 E g S = Z Z 1 2 3 1 2 Number of phenotypes for colour Number of phenotypes for colour
QUESTION 6 The pedigree traces a genetic disease across two generations. Generation [ Key Carrier (not affected) Affected Normal Female O ' Q Generation II Male [l . D The inheritance pattern of this disease can be classified as (A) 1incomplete dominant. (B) autosomal dominant. (C) sex linked. (D) polygenic.
QUESTION 7 In a long-term study of grasshopper colour in a grassland ecosystem it was found that the most abundant phenotype changed from dark green to straw yellow. dark green straw yellow L7 Population Phenotypic trait (colour) This change in the phenotype is an example of (A) diversifying selection. (B) directional selection. (C) stabilising selection. (D) disruptive selection.
QUESTION 10 The forelimbs of humans dogs birds and whales have a very similar pattern of bones. Human Bird Whale Not to scale The similarity of these structures is best explained by which pattern of evolution? (A) convergent evolution (B) divergent evolution (C) parallel evolution (D) coevolution
QUESTION 12 The phenotypic expression of genes is regulated by (A) transcription factors. (B) random fertilisation. (C) DNA polymerase. (D) helicase.
QUESTION 13 Which combination of processes demonstrates spermatogenesis? Where process occurs ® four functional haploid gametes one functional gamete with 2-3 polar bodies
QUESTION 14 Which event could cause a frameshift mutation? (A) non-disjunction during meiosis (B) error during replication (C) Dbase pair substitution (D) heat damage
QUESTION 15 The table identifies the condition associated with a variety of ploidy changes. Chromosome number (ploidy) Trisomy 23 Klinefelter syndrome For a person who has 45 chromosomes (2n—1) due to an autosomal condition which condition do they have? (A) Cri du chat syndrome (B) Down syndrome (C) Klinefelter syndrome (D) Turner syndrome
QUESTION 16 A small group of dingoes migrated to a new area and established a population. After several generations the new population showed a different genetic composition from the original population. This is an example of (A) microevolution and gene flow. (B) macroevolution and gene flow. (C) microevolution and genetic drift. (D) macroevolution and genetic drift.
QUESTION 18 Which scenario would create a selection pressure on a given population? (A) change in fur colour (B) change in weather patterns (C) greater resistance to disease (D) 1mproved ability to locate food sources
QUESTION 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
QUESTION 25 (3 marks) In blood group inheritance in humans three alleles (i I** and I®) determine blood type which can be type O A B or AB. It is known that: o allele I* produces type A and is co-dominant with allele 1B which produces type B « allele 1 produces type O « alleles I* and I® are dominant over allele i. A father who i1s heterozygous type A and a mother who is heterozygous type B have children. Predict the likely frequency of phenotypes for their offspring. Show your working.
QUESTION 26 (4 marks) a) State the three components of a DNA nucleotide. [1 mark] b) Describe the steps involved in DNA profiling. [3 marks]
QUESTION 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. 100% 100% 100% e e | e | w o [ [ | D A ™ a Determine whether the phylogenetic tree has been drawn correctly based on the DNA comparison. Explain your reasoning.
QUESTION 2 (3 marks) a) Explain the difference between exons and introns. [2 marks] b) State a function of telomeres. [1 mark]
QUESTION 4 (2 marks) Explain the purpose of the polymerase chain reaction (PCR) process and provide an example of its application.
QUESTION 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 Duplicated homologous chromosomes Process 2 Duplicated chromosomes . Membrane / . Describe the two processes shown in the diagrams and how they contribute to genetic variation in gametes. Name and description of process I: Name and description of process 2:
QUESTION 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.
QUESTION 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 mangrove bird species.
QUESTION 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 breeding was random throughout the population « an environmental factor was chosen in the simulation to provide selection pressure. The table shows the results of the simulation at the start and after 20 generations. Initial population genotypes Population genotypes after 20 generations BB BB BB BB BB BB BB BB Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb Contrast the initial allele frequency with the allele frequency after 20 generations to draw a conclusion about the effect of the selection pressure on the rabbit population.
QUESTION 10 (3 marks) Describe three ways DNA occurs in cells.
QUESTION 11 (2 marks) Adult skeletal stem cells differentiate into intermediate cells and later into specialised bone tissue types. Skeletal stem cell Intermediate cell Cfi\//ifm@ Compact bone / Cartilage The table shows how three transcription factors (A B and C) affect bone tissue formation. Transcription Intermediate cell Cartilage Compact bone factor role Actlvators Explain the effect of transcription factors on gene expression and tissue formation. Use an example from the table to support your answer.
QUESTION 1 What is the molecular unit of heredity? (A) gene (B) genome (C) nucleotide (D) chromosome
QUESTION 2 Which stage of making recombinant DNA requires DNA ligase? (A) cutting (B) joining (C) 1solation (D) transformation
QUESTION 4 The graph shows the effect of a selection pressure on a hypothetical population. Phenotype Key [ ] Before the selection pressure B 20 generations later Number of individuals Which mode of phenotypic selection corresponds with the data? (A) negative (B) disruptive (C) stabilising (D) directional
QUESTION 6 The role of helicase in DNA replication is to (A) 1nitiate 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.
QUESTION 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.
QUESTION 10 Wings in birds bats and pterosaurs are phenotypically similar though they belong to different families and do not have a common ancestor with the trait. While the general morphology is similar the structure and organisation of each wing is different. This is an example of (A) coevolution. (B) parallel evolution. (C) divergent evolution. (D) convergent evolution.
QUESTION 12 Speciation occurs when (A) the gene pool of an existing species becomes too small to support a viable population. (B) selection pressures cause significant changes to the allele frequencies of a population. (C) genetic drift is no longer occurring within populations. (D) gene flow is no longer occurring between populations.
QUESTION 13 An error during DNA replication resulted in the following change to mRNA transcripts. mRNA before | AUGAAGUUUGGCAUC ... (continued) mRNA after | AUGAAGUUUGCAUCG ... (continued) The DNA replication error most likely involved (A) (B) ©) (D) deletion of cytosine. insertion of guanine. substitution of uracil with guanine. substitution of guanine with cytosine.
QUESTION 14 Prior to fertilisation a secondary oocyte will arrest at which stage of meiosis? (A) prophase I (B) prophase II (C) metaphase I (D) metaphase 11
QUESTION 15 The environment’s influence on gene expression can be investigated by comparing the rate of concordance in monozygotic (identical) and dizygotic (non-identical) twins. Concordance occurs when both twins express a trait. Strong environmental influence is suspected when concordance is (A) higher in monozygotic twins. (B) only observed in dizygotic twins. (C) only observed in monozygotic twins. (D) similar in monozygotic and dizygotic twins.
QUESTION 20 A section of DNA is made up of two strands I and II. Base Strand I Strand II composition | composition owe || e | e wmive | [0 It can be inferred that (A) strand I contains 25% cytosine. (B) strand I contains 32% adenine. (C) strand II contains 29% thymine. (D) strand II contains 71% adenine.
QUESTION 23 (3 marks) Compare microevolution and macroevolution.
QUESTION 26 (4 marks) Karyotypes for two human gametes are shown. Karyotype A (sperm cell) Karyotype B (egg cell) a) Identify which cell exhibits aneuploidy. Refer to evidence from the karyotype. [1 mark] b) Explain how this chromosome abnormality may have occurred. [2 marks] This table lists some genetic conditions resulting from chromosomal abnormalities. Cri du chat syndrome Trisomy 18 Edwards syndrome c) Predict which genetic condition would occur if the two gametes produced a zygote. [1 mark]
QUESTION 27 (2 marks) Explain the purpose of gel electrophoresis in DNA profiling.
QUESTION 28 (3 marks) In 1950 the myxoma virus was released into Australian pest rabbit populations to reduce their numbers. The resulting disease myxomatosis initially wiped out 95% of the rabbit population; however it quickly became less effective as a population control measure. This graph shows the frequency of myxomatosis resistance in Australia’s rabbit population from 1949 to 1956. 100 90 S 5 80 o < = 70 5 2 60 & £ 50 o % = 40 (- o > 30 a 3 g 20 [ 10 'v . — | 1949 1950 1951 1952 1953 1954 1955 1956 Year Use evidence from the graph and the principles of natural selection to explain how myxomatosis became ineffective as a population control measure.
QUESTION 5 (5 marks) a) Describe the roles of messenger RNA and transfer RNA in protein synthesis. [2 marks] b) Explain how transcription factors control cell differentiation using an example. [3 marks]
QUESTION 8 (3 marks) Over time the South African cheetah population has suffered drastic reduction due to periodic droughts disease and hunting. Currently only small isolated populations of cheetahs exist in the wild. Explain in terms of genetic diversity why cheetah populations are now on the verge of extinction.
QUESTION 10 (3 marks) In fruit flies eye colour is a sex-linked trait inherited on the X chromosome. The red-eye allele (R) is dominant over the white-eye allele (r). A red-eyed male and white-eyed female have 50 offspring. Use a Punnett square to predict the number of male and female offspring and their eye colour.
QUESTION 11 (8 marks) Allele frequencies were monitored in two large populations of field mice from neighbouring forests over a 10-year period. Results are shown. Forest X [ e s a) Calculate the allele frequencies for forest Y in 2018. Show your working. [2 marks] b) Identify temporal trends in allele frequency for forests X and Y and infer reasons for the observed differences. [6 marks]
QUESTION 5 Identify which of the following is a factor that regulates phenotypic expression of genes during translation. (A) activator (B) repressor (C) promoter (D) microRNA
QUESTION 6 Which of the following does not cause macroevolution? (A) time (B) mutation (C) extinction (D) speciation
QUESTION 7 The main purpose of gene expression is to (A) transcribe a gene. (B) produce hormones. (C) maintain homeostasis. (D) synthesise a functional gene product.
QUESTION 9 Which of the following is a biotechnological application of DNA profiling? (A) gene therapy (B) food security (C) drug discovery (D) epigenetic analysis
QUESTION 10 This figure is an example of a structure found in DNA. e r—0— Select the option that best represents the figure. (A) histone (B) nucleus (C) chromatin (D) nucleosome
QUESTION 11 A group of genes that control the pattern of body formation in humans is being investigated. A gene that would be part of this group is the (A) HOX (homeotic sub-group) gene. (B) TDF (testis-determining factor) gene. (C) SRY (sex-determining region Y) gene. (D) PAX®6 (regulatory gene of eye and brain) gene.
QUESTION 13 During meiosis II what is the role of homologous chromosomes? (A) pairing (B) separation (C) duplication (D) recombination
QUESTION 16 Haemoglobin gene expression is restricted to erythroid cells. This process is controlled by (A) mutation. (B) translation factors. (C) haemoglobin genes. (D) transcription factors.
QUESTION 18 Evolution during successive generations is a change in the (A) (B) ©) (D) small-scale variation of species’ allele frequencies. genetic transmission of characteristics. genetic composition of a population. divergence of taxonomic groups.
QUESTION 19 Polygenic inheritance is defined as (A) one characteristic controlled by one gene. (B) one characteristic controlled by multiple genes. (C) multiple characteristics controlled by one gene. (D) multiple characteristics controlled by multiple genes.
QUESTION 20 The graphs below show the trait distribution of a hypothetical population before and after selection. The dotted line indicates the mean of each population. Before selection After selection » 40 ; » 40 3] © . 2 £ s 5 o0 s o0 © ° 2 c c . w 20 w 20 : o o 2 10 2 10 £ g - - < 0 : Z 0 : 0 2 4 6: 8 10 12 14 0 2 4 6 : 8 10 12 14 Phenotype mean Phenotype mean The type of phenotypic selection represented in the graphs is (A) divergent. (B) disruptive. (C) stabilising. (D) directional.
QUESTION 21 The figure below represents a section of DNA. LabelIis a (A) nucleotide. (B) covalent bond. (C) hydrogen bond. (D) purine molecule.
QUESTION 22 Island populations are often isolated and can face an increased risk of extinction because of (A) 1improved reproductive fitness. (B) reduced genetic diversity. (C) decreased genetic drift. (D) unrestricted gene flow.
QUESTION 23 Transfer RNA (tRNA) is a type of molecule that helps decode a messenger RNA sequence into a protein. From this information identify which group tRNA belongs to. (A) exons (B) introns (C) noncoding RNA (D) noncoding DNA
QUESTION 24 The figure below shows an evolutionary timeline indicating episodes of evolutionary radiation. Mammals Therapsida Birds Synapsida Sauropsida Archosauria Reptiles Permian Triassic Jurassic Cretaceous Palaeogene Palaeozoic Mesozoic Cenozoic 300 250 200 150 100 50 0 Million years ago (Ma) In which period did the radiation of mammals occur? (A) Triassic (B) Jurassic (C) Cretaceous (D) Palaeogene
QUESTION 26 (4 marks) Explain microevolutionary change through mutation.
QUESTION 27 (4 marks) An experiment compared different strains of bacteria. A wild type (WT) of bacteria and two mutant strains mutant 1 (M1) and mutant (M2) that had different disrupted genes were investigated. Maximal growth rate was used as a determinant of success rate. The results of the experiment are shown below. (a) Competitive ability (b) Growth rate (c) Maximal growth rate 0 ‘“;-_ 0.2 3 0.3 9 2 ~ 0.2 O [ = o 1 © 0.1 O o) — S 0.0 .S_: 0 £ 0.0 c -1 %. —-0.1 0-0.1 = 5 -2 O -0.2 -3-0’—0.2 -3 -0.3 s M1 M2 WT M1 M2 WT M1 M2 WT Strain Strain Strain a) Draw conclusions about the competitive ability and growth rate of the wild type of bacteria used in this experiment. [2 marks] b) Appraise the outcome of the data and determine the success rate of the mutations for this species. [2 marks]
QUESTION 28 (5 marks) The figure below shows a model of ecological niche occupation by species A—E. : T :_¢§ Species D - ‘© 2 | ® % © . m = 2 Z 2 3 Cool Warm Niche axis 2 — Temperature a) Identify which two species are occupying the same ecological niche. [1 mark] b) Species A and B have a common ancestor. Which diversification pattern would have occurred between species A and species B for them to occupy these niches? [1 mark] The table below shows the frequencies of genotypes and phenotypes for a particular trait in a generation of species E. Genotype (% frequency) Phenotype (% frequency) TT (0) Tt (100) tt (0) Phenotype 2 (0) c) Predict the next generation’s genotype and phenotype frequency. Which type of inheritance pattern is represented for Phenotype 17 Phenotype 1 (100) [3 marks]
QUESTION 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.
QUESTION 7 The distributions of phenotypes before and after a selection pressure acted on a population are shown. Which graph shows disruptive selection? === Before selection pressure 25 generations later (A) (B) Number of individuals Number of individuals (C) (D) Number of individuals Number of individuals Phenotype
QUESTION 8 The diagram shows a human karyotype and a list of genetic conditions. HON OE oH G GOR cS OFEOdE OBS OGHE 3k oes Which genetic condition is indicated in the karyotype? (A) Turner syndrome (B) Cri du chat syndrome (C) Edwards syndrome (D) Down syndrome
QUESTION 10 The graph shows extinction rates over time. a ee NO) PPD PS 107 Extinction rate (families per million years a a re 500 450 400 350 300 250 200 ©1506 6100 8§©650 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) 6
QUESTION 11 Restriction enzymes (A) (B) (C) (D) join DNA into a single strand. cut DNA at specific locations. add nucleotides to a growing DNA strand. assist in the amplification of recombinant DNA.
QUESTION 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.
QUESTION 16 The diagram shows a section of DNA. DNA SO Key [_] Introns [3 Exons Immediately following transcription and RNA splicing the product would most closely resemble (A) mRNA: SSS (B) tRNA: _ [RSs (C) mRNA:CL_ TT [ ] (D) tRNA: [[ J J
QUESTION 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
QUESTION 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. | Key — Small plasmids .———- Large plasmids Transformation efficiency (104 cfu/1g) 0.0 0.1 0.2 0.3 0.4 0.5 0.6 CaCl concentration (M) The data suggests that (A) the optimal concentration for transforming small plasmids is 0.15 M. (B) transformation efficiency is highest at concentrations greater than 0.1 M. (C) large plasmids have higher transformation efficiency than small plasmids. (D) there is less variation in transformation efficiency of small plasmids when concentration is less than 0.2 M.
QUESTION 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 through the gel.
QUESTION 24 (5 marks) The frequency of a new allele was monitored in a population of insects over an 18-year period. Frequency 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 graph. [2 marks] b) Explain how mutations can contribute to microevolutionary change in populations [3 marks] that reproduce sexually.
QUESTION 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 offspring.
QUESTION 3 (7 marks) The chart shows the inheritance pattern of a trait which is thought to be sex-linked dominant. Key C] Male with the trait Parents @ Female with the trait Offspring |_] Male without the trait 1-16 used to identify each individual ©) Female without the trait a) Identify how many offspring of individuals 1 and 2 have the trait. [1 mark] b) Identify evidence to support the conclusion that the trait is sex-linked dominant. Justify your response using a Punnett square. [4 marks] c) Infer the genotype of individual 6. Explain your reasoning. [2 marks]
QUESTION 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. a) b) c) Hummingbird hawkmoth Hummingbird Identify the diversification pattern demonstrated by the hummingbird and the hummingbird hawkmoth. [1 mark] Use the principles of natural selection to explain the similarities between the two species. [2 marks] Explain how coevolution of the hummingbird hawkmoth and tube-shaped flowers may have occurred. [2 marks]
QUESTION 8 (3 marks) Explain how temporal isolation can lead to speciation.
QUESTION 5 (3 marks) Nucleic acid sequences were used to investigate evolutionary relationships between four species. Species Nucleic acid sequence GACCGCATTTACGTA GACGTCATATCCGTA a) b) GACCGCATTTCCGTA GACGGCATATCCGTA Explain how data from conserved molecular sequences can be used to estimate time since divergence. Use the data to infer species I-IV in the cladogram. Species Species Species Species I: B. bartonus II: [2 marks] [1 mark] Il:
QUESTION 6 (3 marks) Explain how twin studies can be used to investigate the effect of the environment on gene expression.
QUESTION 5 Which statement is true for DNA replication? (A) (B) (C) (D) Adenine pairs with guanine. The process occurs during metaphase I. DNA polymerase unwinds the double helix. New strands are synthesised in the 5’ to 3’ direction.
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