Free MLPAO Basic Biology, Anatomy, and Physiology Questions and Answers — Questions and Answers
Question 1: Which of the following plated media is enriched?
- MacConkey Agar
- Chocolate Agar (Correct answer)
- Blood Agar
- Thayer Marten Agar
- Muller Hinton Agar
Correct answer: Chocolate Agar
Chocolate Agar is considered an enriched medium because it contains lysed red blood cells, which release essential growth factors like Factor X (hemin) and Factor V (NAD). These factors are crucial for the growth of fastidious bacteria, such as *Haemophilus* species and *Neisseria* species, which cannot grow on basic media like Blood Agar. The enrichment allows for the cultivation of more demanding microorganisms.
Question 2: The administration of CPR on an adult requires how many chest compressions performed immediately before a series of two breaths is given?
- 5
- 0
- 30 (Correct answer)
- 20
- 25
Correct answer: 30
According to current CPR guidelines for adults, the recommended ratio of chest compressions to breaths is 30 compressions followed by 2 breaths. This sequence should be repeated until emergency medical services arrive or the person shows signs of recovery. Maintaining a compression rate of 100-120 compressions per minute is also crucial for effective CPR.
Question 3: Which of the following clinical signs indicates that a person is choking and has complete airway obstruction?
- Coughing or gagging
- Noisy or painful breathing
- No chest movement (Correct answer)
- Inability to speak
- Decreased level of consciousness
Correct answer: No chest movement
In the case of complete airway obstruction due to choking, the person will be unable to move air into or out of their lungs. This directly results in no chest movement (or very minimal, ineffective movement) and an inability to cough, speak, or breathe. The lack of chest movement is a critical sign indicating a complete blockage of airflow.
Question 4: A volumetric flask that is calibrated at 20°C would be expected to contain more volume if the:
- laboratory temperature is 18°C
- liquid is refrigerated before measurement.
- liquid is heated before measurement. (Correct answer)
- flask is refrigerated before measurement.
- flask is at room temperature before measurement.
Correct answer: liquid is heated before measurement.
A volumetric flask is calibrated to contain a specific volume at a standard temperature, typically 20°C. If the liquid is heated before measurement, both the liquid and the flask will expand. However, liquids generally have a higher coefficient of thermal expansion than glass. Therefore, if the flask is filled to the calibration mark with a heated liquid, the actual volume of the liquid contained will be slightly more than the volume the flask was calibrated to hold at 20°C.
Question 5: When urine microscopy is performed, the specimen must be centrifuged at 1,500 3,000 rpm for how many minutes?
- 1
- 3
- 5 (Correct answer)
- 0
- 15
Correct answer: 5
For urine microscopy, the specimen must be centrifuged at 1,500-3,000 rpm for 5 minutes. This specific centrifugation speed and duration are optimized to concentrate the formed elements (cells, casts, crystals) in the urine sediment. It ensures these delicate structures are concentrated enough for microscopic examination without causing excessive damage or distortion, allowing for accurate identification.
Question 6: Which of the following reagents is used for blueing a hematoxylin-stained section?
- Acid solution
- Alcohol solution
- Alkaline solution (Correct answer)
- Methylene blue solution
- Mordant solution
Correct answer: Alkaline solution
After hematoxylin staining, tissue sections typically appear reddish-purple. To achieve the desired blue color, which provides optimal nuclear staining and contrast, the sections are treated with an alkaline solution, a process known as 'blueing.' The alkaline environment converts the reddish-purple hematoxylin dye into a stable, insoluble blue lake.
Question 7: The cellular morphology of a cytological preparation is distorted when smears are:
- left in the fixative solution for longer than 2 hours.
- left in the stain solution for a 1/2 hour.
- left in the clearing solution for a 1/2 hour.
- allowed to dry prior to staining. (Correct answer)
- allowed to dry prior to coverslipping.
Correct answer: allowed to dry prior to staining.
In cytological preparations, allowing smears to air dry prior to fixation and staining causes significant cellular distortion, known as 'air-drying artifact.' This artifact leads to cell shrinkage, nuclear pyknosis, and altered cytoplasmic features, making accurate morphological interpretation difficult or impossible. Prompt fixation, typically with alcohol, is crucial to preserve cellular detail and prevent these artifacts.
Free MLPAO Basic Biology, Anatomy, and Physiology Questions and Answers
Which of the following plated media is enriched?