QCM : Fundamentals of Cell Structure and Function — 8 questions

Explication

The nucleus is a membrane-bound organelle in eukaryotic cells that contains the cell's genetic material (DNA). It acts as the control center of the cell, regulating gene expression and cell activities, which makes option 0 the correct answer.

Explication

Rudolf Virchow proposed the principle that all cells come from pre-existing cells in 1855, which was a pivotal addition to the development of the cell theory.

Explication

Microscopy techniques are primarily used to magnify and resolve cellular and subcellular structures, allowing scientists to observe detailed features of cells that are not visible to the naked eye. Optical microscopes provide general views of cells, while electron microscopes offer high-resolution images of internal and surface structures. The other options are either too specific (chemical analysis), not the main purpose (live cell behavior), or beyond the resolution capabilities of most microscopes (molecular resolution).

Explication

Rudolf Virchow proposed the principle that all cells arise from pre-existing cells in 1855, which was a pivotal contribution to the development of modern cell theory. This principle completed the foundational understanding that cellular life is continuous and reproductive, following earlier work by Schleiden and Schwann, and after Pasteur's experiments that discredited spontaneous generation.

Explication

The phospholipid bilayer mainly provides the structural foundation of the membrane, creating a semi-permeable barrier, while membrane proteins are responsible for specific functions such as transport, signaling, and enzymatic activity within the membrane.

Explication

Peter Mitchell proposed the chemiosmotic theory, which explains how mitochondria generate ATP through a process involving proton gradients across the inner mitochondrial membrane. This theory revolutionized understanding of cellular energy production. The other scientists contributed to biochemistry and microbiology but did not develop this theory.

Explication

Pasteur's experiments disproved spontaneous generation, which supported the idea that cells originate only from pre-existing cells, thereby reinforcing a key principle of cell theory and influencing its development.

Explication

The correct answer is that the division of the nucleus into two nuclei (nuclear division) occurs first during cell division. This ensures that each daughter cell receives an identical set of genetic material before the cytoplasm divides. The other options, such as cytoplasm division or specific stages like anaphase, occur after nuclear division, making them incorrect for the initial event in the process.