Semester_One_Final_Examination_2023_BIOL1020

Semester One Examinations, 2023 BIOL1020 Page 3 of 19 4. Which of the following statements is TRUE? A) Mitochondria are closely related to aerobic respiring Proteobacteria B) Chloroplasts are closely related to photosynthetic Archaea C) The structural similarity between the membrane folds present in mitochondria and specific bacteria is the strongest evidence available that supports the endosymbiont hypothesis D) The thylakoid stacks within mitochondria are a byproduct of the budding off from the cell membrane as outlined in the endosymbiont hypothesis E) While chloroplasts contain their own enzymes and DNA, they do not possess their own ribosomes and therefore lack the ability to their genes into protein. 5. Which of the following statements about ATP is CORRECT? A) ATP stores energy and electrons for anabolic reactions B) ATP is mostly synthesised during glycolysis and consumed in the citric acid cycle C) The hydrolysis of ATP facilitates endergonic reactions D) ATP is a building block of DNA E) The change in Gibbs free energy when ATP is hydrolysed is 7.3 kcal/mol 6 Which of the following statements is INCORRECT? A) ATP pumps protons across the inner membrane of a mitochondrion. B) The transfer of electrons from NADH via four membrane protein complexes leads to a protein gradient across the inner mitochondrial membrane. C) The increased proton concentration in the intermembrane space in a mitochondrion provides potential energy for the production of ATP. D) One molecule of NADH can deliver two electrons to the mitochondrial electron transport chain. E) Only ~34% of the energy stored in a glucose molecule is retained in the ATP that is generated from its catabolism. 7. Which of the following statements is FALSE? A) Centrosomes are anchor points for microtubules and are essential to form the mitotic spindle. B) The contraction of the kinetochore microtubules leads to the separation of the sister chromatids during anaphase. C) In the prophase chromatin condenses into X-shaped chromosomes. D) In the eukaryotic cell cycle the cell spends much more time in the interphase than in the mitotic phase. E) In telophase two nuclear envelopes are fully formed and the cell splits in two via cytokinesis.

Semester One Examinations, 2023 BIOL1020 Page 6 of 19 17. Which of the following statements about translation is/are UNTRUE. A) AUG is the start codon, so cannot exist within an open reading frame. B) Stop codons may exist upstream of an open reading frame in the 5’ untranslated region of the mRNA. C) Introns disrupt open reading frames of eukaryotic genes. D) If two open reading frames are fused with the AUG of the second open reading frame replacing the stop codon of the first open reading frame, protein synthesis will continue past the end of the first open reading frame, resulting in a single protein that is a fusion of the two original proteins. E) Two of the above are untrue. 18. Why do RNA viruses need to supply some of their own enzymes for replication? A) Viruses need the enzymes to enter the cell B) Host cells degrade their own enzymes when viruses enter the cell C) Host cells may lack the polymerase the viruses need to replicate their genomes D) Viruses lack the lipids they need to make envelopes E) Viruses need the enzymes in order to metabolize host cell products 19. If the coding strand of DNA has the sequence 5’-CGAGACTTCTGA-3’, what will the sequence of the transcribed RNA be? A) 5’-CGUGUCTTCTGU-3’ B) 5’-CGAGACUUCUGA-3’ C) 3’-GCTCTGAAGACT-5’ D) 3’-GCUCUGAAGACU-5’ E) 5’-CGAGACTTCTGA-3’ 20. How is DNA arranged in a eukaryotic cell during the G1 phase of interphase? A) in pairs of sister chromatids B) in plasmids C) by microtubule length D) in chromatin fibers E) in condensed chromosomes 21. Sex is inherited as a Mendelian character in mammals. Which of the following sex ratio do you predict: A) 1:2 ratio B) 1:3 ratio C) 2:3 ratio D) 1:1 ratio E) 1:6 ratio

Semester One Examinations, 2023 BIOL1020 Page 9 of 19 27. Where would you normally look to find a prokaryotic genome? A) Within a protein coat B) In the mitochondria C) In the cytoplasm D) In the cell nucleus E) In the extracellular matrix 28. Consider a situation where F1 is backcrossed with one of its parental lineage obtained following F2 genotype progeny in the table below where A and H represent different loci on a chromosome and 1 & 2 are different alleles at those loci. What is the recombination (genetic) distance between the two loci in centimorgan? AxH F2 genotypes # progeny A 1 H 1 /A 2 H 2 380 A 2 H 1 / A 2 H 2 107 A 1 H 2 / A 2 H 2 103 A 2 H 2 / A 2 H 2 410 A) 8.9 B) 21.0 C) 22.5 D) 39.5 E) 5.4 29. How would you tell whether two genes are linked based on the phenotypic results of offspring from a dihybrid cross? A) If the two genes are on different chromosomes, all the offspring will look like the parents B) If the genes are linked, certain combinations of phenotypes will not be observed as often among the offspring of a dihybrid cross C) Linked genes will result in mutations being expressed only in male offspring D) If the genes are not linked, you may calculate offspring ratios using Punnett squares E) If the genes are linked, only one version of each trait is inherited

Semester One Examinations, 2023 BIOL1020 Page 12 of 19 3. In DNA replication, lagging strand synthesis is discontinuous, whereas leading strand synthesis is continuous. What needs to change for lagging strand synthesis to be continuous as well? Use the following terms in your response: DNA polymerase, 5’ to 3’, 3’ to 5’ (3 marks) 4. What are the main differences between cellular respiration and photosynthesis. List at least three aspects where the two processes differ. (4 marks)

Semester One Examinations, 2023 BIOL1020 Page 15 of 19 9. a. What is the function of operons in bacterial gene regulation? (2 marks) b. Provide schematic diagrams of a bacterial operon regulated by repressible proteins (such as the tryptophan operon), in both the “on” and “off” states of the operon. Key elements of your diagram should include: Co-repressor, Genes, mRNA, Operator, Operon, Promoter, Repressor, RNA polymerase (4 marks)

Semester One Examinations, 2023 BIOL1020 Page 18 of 19 14. Why are x-linked recessive traits more common in males? Provide a three- generation pedigree, in which the mother is a carrier and the father is normal, to demonstrate your answer. (3 marks) 15. The Hardy Weinberg theorem or model of p 2 +2pq = q 2 = 1 suggests that genotype frequencies in a population will remain constant through generations in the absence of other evolutionary influences. Explain how this model was derived using a single locus with alleles ‘A’ and ‘a’ and a simple Punnett square (3 marks). What are the major assumptions for this theorem and provide four instances that would void any of these assumptions (2 marks). (5 marks)