ijmb model questions vol1 2019 biology | Practical

Prepare for your exams with ijmb model questions vol1 questions? Reviewing past/model questions is one of the most effective ways to guarantee a high score. This practice hub features authentic 2019 biology (Practical) questions designed to simulate the real exam environment.

Practice these randomly selected questions to test your readiness.

Question 1 View Details
You are provided with a permanent slide of a section of animal epithelial tissue that has been stained with haematoxylin and eosin (H&E). Using a light microscope set at a total magnification of 400×, answer the following questions.
Question Parts
(a)
Identify and name three distinct cellular structures that can be clearly observed in the field of view.
(b)
For each structure named in (a), briefly describe its main function in the cell.
(c)
List two precautions that should be observed when preparing a permanent H&E‑stained slide to avoid artefacts.
(d)
One common source of error that may lead to misidentification of the nucleus is uneven staining. Explain how this error arises and suggest a method to minimise it.
Detailed Essay Solution & Marking Scheme Available

Get the step-by-step mathematical proofs, key points required by examiners, and a comprehensive breakdown from our AI Tutor.

Reveal Answer
Question 2 View Details
You are investigating the mitotic activity of root tip cells of Allium cepa (onion) using a squash preparation. After staining the preparation with aceto‑orcein, you examined a random field under a light microscope (1000× total magnification) and recorded the following numbers of cells in each stage of the cell cycle: - Prophase: 30 cells - Metaphase: 45 cells - Anaphase: 15 cells - Telophase: 10 cells - Interphase (non‑dividing cells): 200 cells Answer the questions that follow.
Question Parts
(a)
Calculate the mitotic index for the sample. Express your answer as a percentage to two decimal places.
(b)
Determine the percentage of cells that are in metaphase relative to the total number of cells observed. Give your answer to one decimal place.
(c)
The normal mitotic index for healthy onion root tips lies between 2 % and 5 %. Based on your calculation in (a), discuss whether the sample appears to be undergoing normal cell division or is possibly affected by a mutagenic agent. Support your argument with reference to the data.
(d)
Suggest two modifications to the experimental procedure that could improve the accuracy of the mitotic index determination.
Detailed Essay Solution & Marking Scheme Available

Get the step-by-step mathematical proofs, key points required by examiners, and a comprehensive breakdown from our AI Tutor.

Reveal Answer
Question 3 View Details
A student is investigating the carbohydrate content of a commercial fruit juice using the Benedict’s test. The student prepares glucose standard solutions of known concentrations (0.2, 0.4, 0.6 and 0.8 g dL⁻¹) and records the absorbance of the orange‑red precipitate at 540 nm after heating. The absorbance readings obtained are 0.12, 0.24, 0.35 and 0.46 respectively. The student then tests 10.0 mL of the fruit juice, obtains an absorbance of 0.38 and records the volume of precipitate formed as 2.5 mL. Answer the following:
Question Parts
(a)
Construct the calibration curve (absorbance versus concentration) and determine the equation of the best‑fit straight line using the method of least squares (assume a linear relationship).
(b)
Using the equation obtained in (a), calculate the concentration of carbohydrate (as glucose equivalent) in the fruit‑juice sample (in g dL⁻¹).
(c)
The student diluted the juice 1 : 1 with distilled water before the test. Determine the original carbohydrate concentration in the undiluted juice.
(d)
Discuss two possible sources of systematic error in this experiment and how each could affect the calculated carbohydrate content.
Detailed Essay Solution & Marking Scheme Available

Get the step-by-step mathematical proofs, key points required by examiners, and a comprehensive breakdown from our AI Tutor.

Reveal Answer
Question 4 View Details
A group of students study the effect of temperature on the rate of respiration in germinating mung‑bean seeds using a closed respirometer (BOD bottle). Ten seeds (average mass 0.12 g each) are placed in the bottle containing 200 mL of water at a given temperature. The bottle is sealed with a rubber stopper fitted with a graduated gas syringe (capacity 50 mL) that records the decrease in gas volume due to O₂ consumption. The syringe is initially set to 0 mL (fully extended). After 30 min the syringe indicates a contraction of 4.2 mL at 25 °C and 1 atm. The experiment is repeated at 35 °C and the contraction after 30 min is 7.5 mL. Answer the following:
Question Parts
(a)
Calculate the rate of O₂ consumption (in mL O₂ g⁻¹ min⁻¹) at each temperature.
(b)
Assuming a respiratory quotient (RQ) of 1.0 for carbohydrate metabolism, estimate the amount of carbohydrate (as glucose) metabolised per gram of seed in the 30‑minute period at each temperature (expressed in g g⁻¹).
(c)
Using the data, determine the Q₁₀ temperature coefficient for respiration between 25 °C and 35 °C.
(d)
Provide two physiological reasons why respiration rate increases with temperature, and discuss one limitation of the Q₁₀ calculation in this experimental context.
Detailed Essay Solution & Marking Scheme Available

Get the step-by-step mathematical proofs, key points required by examiners, and a comprehensive breakdown from our AI Tutor.

Reveal Answer

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows
Help others prepare! Share this practice hub:
Chat with Support