Microbiology Lab Practical 1 (Pearson Education Edition) Exam 2025 Questions & Answers with 100% Correct Answers | Verified

What bacterial shape is observed? - Bacillus What bacterial shape is observed? - Coccus What bacterial shape is observed? - Spiral/spirochete How does increase in magnification affect field of vision? - It makes it smaller How does increased magnification affect depth of field? - Depth of field becomes larger Why is it desirable that microscope objectives be parfocal? - So each objective does not require further focusing Which objective focuses the closest to the slide when it is in focus? - The dry-oil / oil lens objective Which controls on the microscope affect the amount of light reaching the ocular lens? - The rheostat and the diaphragm Assume the diameter of the field of vision in your microscope is 2mm under low power. If one Bacillus cell measures 2 um, how many Bacillus cells could fit end-to-end across the field? - 2,000 Bacillus cells at 2mm low power How many 10 um yeast cells could fit across the field? - 200 yeast cells at 2mm low power What are the advantages of the low-power objective over the oil immersion / dry-oil objective for viewing fungi or algae? - The organism can be viewed in its entirety, rather than being limited to only one area and one plane at a time