Railway Science (Biology – Cell : Basic Unit of Life) (Part-II)

When water enters the guard cells, they become turgid (swollen) due to increased pressure inside them. This change in pressure causes the pore between the two guard cells to open, allowing for gas exchange (CO₂ intake and O₂ release) to occur in the plant.

Other characteristics of plant cells: Vacuoles are usually large, plastids present, Golgi body present in the form of units known as dictyosomes, Centriole is absent.

The cell wall is a characteristic structure of fungi and is composed mainly of glucans, chitin, and glycoproteins. As the components of the fungal cell wall are not present in humans, this structure is an excellent target for antifungal therapy.

The tissue that makes a plant hard and strong is called Sclerenchyma. The cells of sclerenchyma tissue have their walls thickened due to the presence of lignin. Sclerenchyma tissue is a type of permanent tissue found in plants. It is formed by the combination of dead cells.

Cyton is also called a cell body or perikaryon. It has a central nucleus with abundant cytoplasm called neuroplasm. The cytoplasm contains a large granular body known as Nissl's granules, as well as many other cell organelles such as mitochondria.

It is the organic compound composed of the phosphate groups, adenine, and the sugar ribose.These ATP molecules are synthesized by Mitochondria, therefore it is called powerhouse of the cell. The ATP is used for various cellular functions, including transportation of different molecules across cell membranes.

A neuron is a microscopic structure composed of three major parts, namely, the cell body (also known as the soma), dendrites and axon. Dendrites receive signals from other neurons or sensory receptors and transmit them toward the cell body. The axons transmit nerve impulses away from the cell body to a synapse (connections with other neurons) or to a neuro-muscular junction (connections with muscles).

Red blood cells - Made in Bone marrow. Function - It carries oxygen. It removes Carbon Dioxide from our body. Life Span - 120 days. Normal RBC range - Male (4.7 to 6.1 million cells/mcL), Female (4.2 to 5.4 million cells/mcL).
Other types of blood cells: White Blood cells - Its Function is to protect us against illness and disease. Life Span: 12-20 days. Platelets - A small, colorless cell fragments in our blood that form clots and stop or prevent bleeding. Life Span: 8-10 days.

Muscles are inherently multicellular structures composed of specialized cells called muscle fibers. A unicellular organism, also known as single-celled, consists of one cell, unlike multicellular organisms. They are categorized into prokaryotic and eukaryotic types. Examples include bacteria, protists, and yeast.