TAMU BIOLOGY LAB PRACTICAL REVIEW EXAM WITH CORRECT ACTUAL QUESTIONS AND CORRECTLY WELL DEFINED ANSWERS LATEST ALREADY GRADED A+

TAMU BIOLOGY LAB PRACTICAL REVIEW
EXAM WITH CORRECT ACTUAL
QUESTIONS AND CORRECTLY WELL
DEFINED ANSWERS LATEST ALREADY
GRADED A+




1. Which microscope part controls light intensity?


A. Objective lens
B. Stage
C. Diaphragm
D. Eyepiece


Answer: C. Diaphragm
Explanation: The diaphragm regulates the amount of light
reaching the specimen, improving contrast and clarity.


2. Total magnification is calculated by:

,A. Adding lenses
B. Multiplying eyepiece × objective
C. Dividing eyepiece by objective
D. Subtracting lenses


Answer: B. Multiplying eyepiece × objective
Explanation: Total magnification = ocular lens (usually 10x)
multiplied by objective lens.


3. Which stain is used to identify Gram-positive bacteria?


A. Safranin
B. Crystal violet
C. Iodine
D. Alcohol


Answer: B. Crystal violet
Explanation: Gram-positive bacteria retain crystal violet due
to thick peptidoglycan walls.

,4. What is the function of iodine in Gram staining?


A. Decolorizer
B. Counterstain
C. Mordant
D. Fixative


Answer: C. Mordant
Explanation: Iodine binds crystal violet, helping it stay in
Gram-positive cells.


5. Which macromolecule is tested using Benedict’s reagent?


A. Lipids
B. Proteins
C. Reducing sugars
D. Starch


Answer: C. Reducing sugars
Explanation: Benedict’s reagent detects glucose and other
reducing sugars.

, 6. A positive Benedict’s test turns the solution:


A. Blue
B. Green to orange/red
C. Purple
D. Clear


Answer: B. Green to orange/red
Explanation: Color intensity reflects sugar concentration.


7. Which indicator tests for starch?


A. Biuret
B. Iodine
C. Sudan IV
D. Benedict’s


Answer: B. Iodine
Explanation: Iodine turns blue-black in the presence of
starch.