Selected MCQ

Current Question
In the mitochondrion, where are the electron transport chain complexes located?
  • A. Outer mitochondrial membrane
  • B. Mitochondrial matrix
  • C. Inner mitochondrial membrane
  • D. Intermembrane space
Correct Answer: C
Explanation:
The inner membrane houses complexes I–IV of the electron transport chain and ATP synthase, creating the proton gradient.
Related Question 1
Which term describes genes that are located on the same chromosome and inherited together more often than by chance?
  • A. Linked genes
  • B. Epistatic genes
  • C. Polygenic genes
  • D. Independent genes
Correct Answer: A
Explanation:
Linked genes are near each other on the same chromosome. They tend to be inherited together, and their recombination frequency is less than 50%.
Related Question 2
Sanger (dideoxy) sequencing terminates DNA chain elongation using:
  • A. Restriction enzymes
  • B. Dideoxynucleotides (ddNTPs)
  • C. RNA polymerase
  • D. DNA methyltransferases
Correct Answer: B
Explanation:
In Sanger sequencing, modified nucleotides (ddNTPs) lacking a 3′-OH terminate extension when incorporated, allowing determination of the DNA sequence by fragment lengths.
Related Question 3
The sodium-potassium pump (Na⁺/K⁺-ATPase) is an example of which type of membrane transport?
  • A. Passive diffusion
  • B. Facilitated diffusion
  • C. Primary active transport
  • D. Secondary active transport
Correct Answer: C
Explanation:
Na⁺/K⁺-ATPase uses ATP directly to pump Na⁺ out and K⁺ in against their gradients, classifying it as primary active transport.
Related Question 4
Which motor protein transports vesicles toward the plus end of microtubules (generally the cell periphery)?
  • A. Kinesin
  • B. Dynein
  • C. Myosin
  • D. Actin
Correct Answer: A
Explanation:
Kinesin moves cargo anterogradely toward microtubule plus ends (cell periphery). Dynein moves cargo retrogradely (toward minus ends).
Related Question 5
Which statement correctly describes the role of nuclear pore complexes in eukaryotic cells?
  • A. They allow passive diffusion of all proteins smaller than ~100 kDa
  • B. They actively transport large molecules into and out of the nucleus
  • C. They separate the nuclear interior from the cytosol without any transport
  • D. They are the sites where rRNA is transcribed and processed
Correct Answer: B
Explanation:
Nuclear pore complexes selectively transport large molecules (such as mRNA and proteins with nuclear localization/export signals) between the nucleus and the cytoplasm. Small molecules can diffuse passively up to ~40 kDa.