Cell Biology and Structure

SO2 primarily affects the entire cell membrane system by dissolving in cellular fluids to form sulfurous acid. This acidic disturbance damages plasma membranes and internal organelle membranes, disrupting membrane integrity, transport processes, and cellular homeostasis. The nucleus, cell wall, and plasmodesmata are not the primary targets.

The spindle pole body (SPB) is the microtubule organising centre in yeast cells, functionally equivalent to the centrosome. Unlike the centrosome the SPB does not contain centrioles. The SPB organises the microtubule cytoskeleton, which plays many roles in the cell. It is important for organising the spindle and thus in cell division.

This is the correct option as ciliated tissue is not a connective animal tissue. It is an epithelial animal tissue.

This is the correct option. Prokaryotic cells are not connective tissues. A prokaryote is a single-celled organism that lacks a membrane-bound nucleus, mitochondria, or any other membrane-bound organelles.

This is the correct option as nervous tissues are the tissues that specialise in transmitting messages within our body. They contain neurons that have the ability to receive stimuli from within or outside the body and to conduct impulses to different parts of the body.

This is the correct option as this is not a characteristic of the meristematic tissue. Cytoplasm is dense in it. Vacuoles are nearly absent.

Metachromasis is the phenomenon of certain tissues and cell components showing colour other than their fundamental one, e.g. basic aniline stain.

Langerhans cells are dendritic cells located at suprabasal layers.

Keratinosomes take part in destruction of organelle's membrane.

 Protein synthesis in an animal cell occurs in ribosomes present in cytoplasm as well as in mitochondria.

 The main organelle involved in modification and routing of newly synthesized proteins to their destinations is endoplasmic reticulum.The endoplasmic reticulum serves many general functions, including the folding of protein molecules in sacs called cisternae and the transport of synthesized proteins in vesicles to the Golgi apparatus.

 Neurons are least likely to regnerate when lost . They have least power of regeneration.

Regeneration is carried out by specialized cells that have the ability to proliferate and differentiate into various cell types. In organisms like Planaria, these specialized cells (called neoblasts) can regenerate entire body parts. Regular body cells or differentiated cells have lost this capacity.

The pyrenoid structures of Spirogyra stores starch.

Mitochondria are organelles that generate most of the cell's ATP supply through cellular respiration (Krebs cycle and electron transport chain). This energy production role has earned them the nickname 'powerhouse of the cell'. They have their own DNA and are thought to have originated from ancient bacteria.