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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 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 5 (4 marks) Explain the process of protein synthesis in terms of transcription and translation.
QUESTION 12 The phenotypic expression of genes is regulated by (A) transcription factors. (B) random fertilisation. (C) DNA polymerase. (D) helicase.
QUESTION 2 (3 marks) a) Explain the difference between exons and introns. [2 marks] b) State a function of telomeres. [1 mark]
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 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 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 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 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 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 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 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 6 (3 marks) Explain how twin studies can be used to investigate the effect of the environment on gene expression.
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