20 MCQ on Cell Structure for Competitive Exams

Neurons, or nerve cells, are the longest cells in the human body.

Nucleus is centrally located in most of the cells. However, it may also be in the periphery of the cell, as in the case of plant cells.

The nucleoplasm is the gel-like substance inside the nucleus that contains chromatin and the nucleolus. It is composed of water, ions, enzymes, and molecules necessary for nuclear functions.

The nuclear membrane directly encloses the nucleus, separating it from the cytoplasm.

The nuclear membrane surrounds the nucleus and regulates the passage of materials between the nucleus and the cytoplasm.

Chromatin is a network of DNA and proteins found inside the nucleus.

Nuclear pores are openings in the nuclear membrane (nuclear envelope) that allow to regulate the selective transport of molecules between the nucleus and the cytoplasm.

Ribosome synthesis occurs in the nucleolus, not the nuclear membrane.

RNA molecules can pass through nuclear pores to travel from the nucleus to the cytoplasm, where they are translated into proteins.

The protoplasm outside the nucleus is called cytoplasm. The cytoplasm is the jelly-like substance present between the nucleus and the plasma membrane. It contains organelles such as mitochondria, ribosomes, and the endoplasmic reticulum, which are responsible for various cellular functions. Cytoplasm includes all protoplasm except the nucleus.

Protoplasm is called a physical basis of life. It encompasses all living parts of the cell, such as cytoplasm, nucleus, and organelles.

In 1839, the Czech physiologist Jan Evangelista Purkyně (also spelled Purkinje) first used the term to describe the gelatinous substance inside cells.

The Protoplasm Theory was primarily formulated by Max Schultze in 1861 and further developed by Oscar Hertwig and T.H. Huxley.

Protoplasm is ~90% water and contains organic compounds like proteins, lipids, and nucleic acids.

Cytosol is the fluid matrix of the cytoplasm where organelles are suspended.

The cell wall is a non-living structure outside the cell membrane in plants, fungi, or bacteria.

Proteins form a colloidal solution in water, allowing protoplasm to behave like a gel/sol.

Huxley coined this phrase in 1868 to emphasize the role of protoplasm as the fundamental living material.

The most abundant molecule in protoplasm is water (making up ~70-90% of its weight), but the most abundant elements (by weight) are O > C > H > N.

The plasma membrane (cell membrane) is a selectively permeable barrier that regulates the entry and exit of substances, maintaining the internal environment of cell.