Waec Model Questions Vol1 2025 Biology Question 13

Practice objective / multiple choice question 13 from the 2025 Waec Model Questions Vol1 Biology examination.

Waec Model Questions Vol1 2025 Biology Objective / Multiple Choice Hard Difficulty
Question 13 WAEC_MODEL_QUESTIONS_VOL1 • 2025 • BIOLOGY • objective

A bacterial culture is inoculated with 10³ cells at 30 °C. At this temperature the bacteria exhibit a lag phase of 2 h followed by exponential growth with a generation time of 30 min. At 40 °C the lag phase shortens to 1 h but the generation time lengthens to 45 min. After 4 h of incubation at 30 °C the culture is shifted to 40 °C and then incubated for a further 4 h. Assuming no cell death and that the temperature shift does not affect cells already in exponential phase, calculate the total number of cells present after the full 8 h period. Give your answer in scientific notation to two significant figures.

Answer Options

A. 4.2×10⁵
B. 8.1×10⁵
C. 5.9×10⁴
Correct Answer D. 6.5×10⁵
Correct Answer
D
Correct Option:
6.5×10⁵

About This Question

This is Waec Model Questions Vol1 2025 Biology Question 13. It is one of the objective questions from the 2025 Waec Model Questions Vol1 Biology examination.

Difficulty level: Hard .

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