Why are the mitochondria often called the powerhouse of the cell?

The cell membrane, also known as the plasma membrane, contains two layers of phospholipids arranged in a bilayer structure. Each phospholipid molecule consists of a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) tails. In the bilayer structure, the hydrophilic heads face outward, interacting with the aqueous environments both inside and outside the cell, while the hydrophobic tails face inward, shielded from the surrounding water. This arrangement forms a barrier that separates the internal environment of the cell from the external environment, regulating the passage of substances into and out of the cell.

The flagellum is a whip-like structure found in many single-celled protists, bacteria, and sperm cells of animals. Its primary purpose is propulsion, enabling the cell to move through its environment. The flagellum achieves propulsion by undergoing a whip-like motion, either beating rhythmically to propel the cell forward or rotating like a propeller. This movement allows the cell to navigate toward nutrients, avoid harmful substances, or seek optimal environmental conditions for survival and reproduction.

The cellular membrane, also known as the plasma membrane or phospholipid bilayer, is primarily composed of lipids, specifically phospholipids. Phospholipids are molecules with hydrophilic (water-attracting) heads and hydrophobic (water-repelling) tails. These phospholipids arrange themselves into a bilayer structure, with the hydrophilic heads facing outward toward the aqueous environments inside and outside the cell, while the hydrophobic tails are sandwiched in between. Additionally, the cellular membrane contains proteins, carbohydrates, and cholesterol, which play various roles in maintaining membrane structure, cell signaling, and cell recognition.

Glycolysis is the first step in the process of cellular respiration, which is the metabolic pathway by which cells generate ATP (adenosine triphosphate), the energy currency of the cell. Glycolysis occurs in the cytoplasm and involves the breakdown of glucose, a six-carbon sugar, into two molecules of pyruvate, a three-carbon compound. During glycolysis, glucose is oxidized and ATP is produced through substrate-level phosphorylation. Glycolysis is anaerobic, meaning it does not require oxygen, and is common to both aerobic and anaerobic respiration pathways.