MCQs

The organ of Corti sits on the basilar membrane within the cochlear duct (scala media), which is filled with endolymph. The scala vestibuli and scala tympani contain perilymph.

Meissner's corpuscles are rapidly adapting, encapsulated receptors found just beneath the epidermis in hairless skin, specializing in fine, discriminative touch.

Fast, sharp pain (like a needle prick) is transmitted rapidly by myelinated A-delta fibers. Slow, dull, aching pain is transmitted by unmyelinated C fibers.

Rhodopsin consists of opsin protein bound to retinal. Retinal is a light-absorbing molecule synthesized directly from Vitamin A (retinol). Vitamin A deficiency leads to night blindness.

A generator potential is a graded depolarization in the sensory nerve ending itself. If it reaches threshold, it opens voltage-gated sodium channels at the first node of Ranvier, firing an action potential.

The adequate stimulus is the specific form of energy (light, mechanical, chemical) to which a receptor is uniquely adapted and most sensitive, having the lowest threshold for activation. It is not the only energy that can activate it (e.g., a hard punch to the eye causes seeing "stars").

Blocking the kinetochores prevents microtubule attachment at the centromere, interrupting mitotic checkpoints and halting orderly chromosome separation.

Blocking the kinetochores prevents microtubule attachment at the centromere, interrupting mitotic checkpoints and halting orderly chromosome separation.

Blocking the kinetochores prevents microtubule attachment at the centromere, interrupting mitotic checkpoints and halting orderly chromosome separation.

Blocking the kinetochores prevents microtubule attachment at the centromere, interrupting mitotic checkpoints and halting orderly chromosome separation.

Blocking the kinetochores prevents microtubule attachment at the centromere, interrupting mitotic checkpoints and halting orderly chromosome separation.

Blocking the kinetochores prevents microtubule attachment at the centromere, interrupting mitotic checkpoints and halting orderly chromosome separation.

Blocking the kinetochores prevents microtubule attachment at the centromere, interrupting mitotic checkpoints and halting orderly chromosome separation.

Blocking the kinetochores prevents microtubule attachment at the centromere, interrupting mitotic checkpoints and halting orderly chromosome separation.

Blocking the kinetochores prevents microtubule attachment at the centromere, interrupting mitotic checkpoints and halting orderly chromosome separation.

Blocking the kinetochores prevents microtubule attachment at the centromere, interrupting mitotic checkpoints and halting orderly chromosome separation.

Blocking the kinetochores prevents microtubule attachment at the centromere, interrupting mitotic checkpoints and halting orderly chromosome separation.

Heterochromatin remains heavily condensed throughout the cell cycle and contains dense, methylated DNA sequences that are mostly transcriptionally silent.

Somatic chromosome consistency relies on high-fidelity DNA replication during S-phase followed by symmetrical separation of sister chromatids to daughter nuclei during mitosis.