Cell Biology and Structure

Rough endoplasmic reticulum has ribosomes on its surface for synthesising proteins. Ribosomes make the endoplasmic reticulum rough.

Arbiskov cells are seen in myeloblastoma.

Zone of stimulation is characterised by fibroblasts and osteoblasts.

Lysosomes are membrane-bound organelles that contain digestive enzymes called hydrolases. These enzymes break down various biomolecules (proteins, lipids, carbohydrates, nucleic acids) through hydrolysis. Ribosomes are for protein synthesis, mesosomes are bacterial membrane invaginations, and peroxisomes contain oxidases, not hydrolases.

The lipid bilayer forms the fundamental structure of the plasma membrane, creating a selectively permeable barrier that controls the movement of substances in and out of the cell. While mitochondria also have lipid bilayers, the plasma membrane is the primary example.

The acrosome is a specialized organelle derived from the Golgi apparatus that develops over the anterior half of the sperm nucleus. It contains digestive enzymes that help the sperm penetrate the egg's outer layers during fertilization.

In Amoeba, osmoregulation (water balance) is performed by the contractile vacuole, which collects excess water and expels it from the cell. Ectoplasm is the outer gel layer, pseudopodia are for locomotion, hyaloplasm is the inner fluid, and food vacuoles digest nutrients.

Nematoblasts (also called cnidoblasts) are specialized cells in Cnidaria that develop into stinging cells (cnidocytes). They are derived from interstitial cells (I-cells), which are multipotent stem cells in cnidarians. Gland cells, mesoepithelial cells, and nerve cells do not give rise to nematoblasts.

Spindle fibers are composed of microtubules - hollow protein tubes made of tubulin that pull chromosomes apart during cell division. The spindle apparatus is entirely microtubule-based. ER, Golgi, peroxisomes, and mesosomes play no role in spindle formation.

The tonoplast is a specialized membrane that surrounds vacuoles in plant cells. It regulates transport of materials in and out of the vacuole, maintaining the vacuole's internal environment.

This is the correct option, as this statement is false. The cell is enclosed by the cell membrane which surrounds a jelly-like substance known as cytoplasm, is the correct statement.

Thesocytes are specialized cells in sponges that store food reserves, particularly nutrients and lipids. Archaeocytes are totipotent cells, scleroblasts produce spicules, and pinocytes are related to pinacoderm (covering layer). Option A appears to have a typo.

George Emil Palade discovered ribosomes in the 1950s using electron microscopy techniques. He identified these small, dense particles in the cytoplasm that were involved in protein synthesis. This discovery, along with his work on membrane-bound organelles, earned him the 1974 Nobel Prize in Physiology or Medicine.

Lysosomes contain digestive enzymes (hydrolases) that break down various cellular waste materials, carbohydrates, proteins, lipids, and foreign material. Mitochondria produce ATP, ribosomes synthesize proteins, and the Golgi complex processes and packages molecules.

Polyribosomes (polysomes) are clusters of ribosomes that simultaneously translate a single mRNA molecule, and they are found free-floating in the cytoplasm of cells. This arrangement allows for efficient protein synthesis as multiple ribosomes can work on the same mRNA strand to produce multiple copies of the same protein rapidly. While some ribosomes attach to the endoplasmic reticulum (for secretory proteins), polyribosomes themselves are primarily cytoplasmic structures.