Cell Biology and Structure

Animal cells contain lysosomes for waste digestion and centrosomes for organizing cell division, which are generally absent in plant cells. Both cell types share mitochondria for energy production and ribosomes for protein synthesis.

Proteins are the most abundant organic molecules in cytoplasm, serving as enzymes that catalyze reactions and as structural components. While water is the major component overall, it's inorganic, and lipids and sugars are present in smaller amounts than proteins.

Protoplasm encompasses all living parts of the cell: the plasma membrane, cytoplasm, and nucleus. The cell wall is an extracellular structure in plants, fungi, and bacteria and is not considered part of the protoplasm.

Animal cells lack cell walls, which are rigid outer structures found in plant cells (made of cellulose), fungal cells (chitin), and bacterial cells (peptidoglycan). This allows animal cells to be more flexible and change shape.

Cyclosis (cytoplasmic streaming) in Paramecium primarily aids in the movement and circulation of food vacuoles during digestion. It distributes nutrients but is not primarily for excretion, locomotion, or reproduction.

Eukaryotic cells have a true nucleus surrounded by a double membrane and membrane-bound organelles like mitochondria and ER. Prokaryotic cells lack these features, and unicellular refers to number of cells, not cell type.

Cytoplasm is a jelly-like substance which is present all around the nucleus in which cell organelles are placed. Cell membrane is the outer covering of a cell that separates the interior of all cells from the outside environment. Nuclear membrane is the membrane, which surrounds the central nucleus. Nucleoplasm is a jelly-like substance present in the nucleus. 

In cell, nucleus containing the hereditary materials is located in the centre. It is spherical in shape. Mitochondria, food vacuole and golgi body are the other cell organelles but they are not located in the centre.

The outermost layer of epidermis called 'stratum corneum' consists of flattened dead cells, which are made of a horny protein named keratin.

Cell wall prevents over-expansion when water enters the cell.

Cells interact with each other through plasmodesmata, which are inter-connecting channels of cytoplasm that connect to the protoplasts of adjacent cells across the cell wall.

Hydraulic turgor pressure creates rigidity in cell walls.

Hydroxyproline is present in water mold cell wall, but absent in fungal wall.

The root endodermis is the cylindrical boundary that separates the inner vascular tissue from the outer cortex. It is the innermost layer of cortex formed by compactly arranged barrel-shaped cells. Some of the cells in the endodermis are thin-walled and are known as passage cells. The passage cells allow water to pass into the xylem vessels.