Cell Biology and Structure

Amoeba exhibits cellular level of organization because it is a unicellular organism - all life functions (nutrition, respiration, reproduction) occur within a single cell. Tissue, organ, and organ system levels require multicellular organisms with specialized cell groups.

Nerve cells (neurons) are post-mitotic, meaning they lose their ability to divide after reaching maturity. This is why brain damage from injury or stroke is often permanent. Blood cells, muscle cells, and bone cells retain regenerative capacity through stem cells.

Cell sap refers to the fluid inside plant cell vacuoles, which is a solution of water containing dissolved salts, sugars, and other substances. This solution helps maintain turgor pressure and stores nutrients and waste products.

In unicellular organisms like protozoa (e.g., Amoeba), food vacuoles are responsible for digesting food through intracellular digestion. This is analogous to how multicellular organisms have entire digestive systems to break down food.

These are lipids containing a phosphate group. A phospholipid molecule has a strongly nonpolar and hydrophobic (water insoluble) tail region represented by fatty acid chains and a strongly polar or hydrophilic (water soluble) head region represented by the phosphate group. Such an arrangement forms a basic component of plasma membranes.

 Conversion of carbohydrates into amino acids in plants occur in mitochondria.

  In sieve tube cells, golgi complex is absent. The main function of the sieve tube is transport of carbohydrates, primarily sucrose, in the plant (e.g., from the leaves to the fruits and roots).

The cells that are rigid and full of water are called turgid.

These are the cell organelles derived from endoplasmic reticulum and are involved in storage and synthesis of fat.

It is involved in storage and synthesis of fat.

An uncoupling protein is a mitochondrial inner membrane protein that can dissipate the proton gradient before it can be used to provide the energy for oxidative phosphorylation.

Yes, planaria shows the process of regeneration.

An inducible gene is a gene whose expression is either susceptible to environmental change or dependent on the position in the cell cycle.

Growing viruses in cell cultures allow preparation of purified viruses for the manufacture of vaccines. The injectable polio vaccine developed by Jonas Salk was one of the first products mass-produced using cell culture techniques. This vaccine was made possible by the cell culture research of John Franklin Enders, Thomas Huckle Weller and Frederick Chapman Robbins, who were awarded a Nobel Prize for their discovery of a method of growing the virus in monkey kidney cell cultures.

Acrosome is formed of the golgi complex.