Prepare with MCQs
Thousands of verified questions for competitive exams
25K+
MCQs
15+
Categories
500+
Tests
Free
Access
All
๐ General Knowledge
๐ Current Affairs
๐ต๐ฐ Pakistan Affairs
โช Islamic Studies
๐ค English
๐ป Computer
๐งฎ Mathematics
โ Physics
๐งช Chemistry
๐งฌ Biology
๐ฌ Everyday Science
๐ฉโ๐ซ Pedagogy
ุงุฑุฏู Urdu
๐บ World Geography
๐ History
Biology
In which specific part of the mitochondrion does the citric acid cycle (Krebs cycle) take place?
A
Inner mitochondrial membrane
B
Mitochondrial matrix
C
Intermembrane space
D
Outer membrane
Correct Answer
B
Biology
What zone of an aquatic ecosystem receives enough sunlight to allow photosynthesis to occur?
A
Aphotic zone
B
Photic zone
C
Benthic zone
D
Abyssal zone
Correct Answer
B
Biology
What molecular technique allows scientists to make millions of copies of a specific DNA segment rapidly for research or forensic analysis?
A
Gel electrophoresis
B
Western blotting
C
Polymerase chain reaction (PCR)
D
DNA sequencing
Correct Answer
C
Biology
Which hormone, released by the posterior pituitary gland, acts directly on the kidneys to increase water reabsorption and concentrate the urine?
A
Aldosterone
B
Antidiuretic hormone (ADH)
C
Insulin
D
Cortisol
Correct Answer
B
Biology
What complex carbohydrate do plants use as their primary energy storage molecule, consisting of a long chain of glucose units?
A
Cellulose
B
Glycogen
C
Starch
D
Chitin
Correct Answer
C
Biology
According to the sliding filament theory, which structural unit of a myofibril serves as the basic functional unit of muscle contraction?
A
Sarcomere
B
Sarcolemma
C
Sarcoplasm
D
Myosin head
Correct Answer
A
Biology
What type of directional growth response occurs when a plant grows or bends toward a light source?
A
Thigmotropism
B
Geotropism
C
Phototropism
D
Hydrotropism
Correct Answer
C
Biology
Which powerful digestive enzyme is activated in the stomach to begin the chemical breakdown of proteins into smaller peptides?
A
Amylase
B
Lipase
C
Trypsin
D
Pepsin
Correct Answer
D
Biology
What term describes the random fluctuation of allele frequencies in a population over time, which typically has a much larger impact on smaller populations?
A
Gene flow
B
Natural selection
C
Genetic drift
D
Artificial selection
Correct Answer
C
Biology
Which class of proteins acts as the primary regulators of the cell cycle, controlling a cell's progression through various checkpoints?
A
Histones
B
Cyclins
C
Immunoglobulins
D
Actins
Correct Answer
B