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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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 21 The figure below represents a section of DNA. LabelIis a (A) nucleotide. (B) covalent bond. (C) hydrogen bond. (D) purine molecule.
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 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 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 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 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 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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