The diagram (described in text) shows a cross-section of a human lung alveolus and a fish gill filament.
(d) If the experiment used germinating mung beans instead of crickets, how would the results differ? Why? (2 marks)
(b) Explain the concept of countercurrent exchange in fish gills and explain why it is more efficient than concurrent flow. (4 marks)
A student uses a respirometer to measure oxygen consumption in crickets at 20°C and 30°C. singapore junior biology olympiad past papers
(c) If 320 offspring are produced, how many are expected to have purple flowers and pointed leaves? Show your working. (2 marks)
Below is a structured set of original questions (Section A: Multiple Choice, Section B: Structured/Free Response), followed by a detailed answer key and performance analysis guide. Subject: Junior Biology Olympiad Time: 1 hour 30 minutes (simulated) Total Marks: 60 Section A: Multiple Choice (30 marks) Questions 1 to 15. Each correct answer earns 2 marks. Select the single best answer.
(c) The student forgot to include a control vial with glass beads (no crickets). Explain why a control is necessary. (2 marks) The diagram (described in text) shows a cross-section
In Arabidopsis thaliana , flower color is controlled by a single gene with two alleles: Purple (P) dominant over white (p). Another unlinked gene controls leaf shape: Round (R) dominant over pointed (r).
A plant with purple flowers and round leaves (heterozygous for both traits) is self-crossed.
(a) State the genotype of the parent plant. (1 mark) (2 marks) (b) Explain the concept of countercurrent
This is a development of modeled exactly on the style and difficulty of the Singapore Junior Biology Olympiad (SJBO) . Since actual past papers are copyrighted, this serves as a faithful simulation for training.
(d) Name the principle illustrated by the independent assortment of these two genes. (1 mark)
(a) Draw a labeled diagram of a simple respirometer suitable for this experiment. (3 marks)
(b) Predict the relative rate of oxygen consumption at 30°C vs 20°C. Explain your answer in terms of enzyme kinetics and metabolic rate. (3 marks)
(a) List two structural adaptations of the alveolus that maximize gas exchange. (2 marks)