Mitochondria generate the energy that a cell needs to function properly. They are often described as the powerhouse of the cell. They are also involved in signaling, cellular differentiation, cell death, maintenance of cell growth and control of the cell cycle.
Mitochondria create chemical energy in the form of a chemical called adenosine triphosphate through a machinery known as the electron transport chain. The chain is created by four complexes created of groups of proteins and a fifth complex that is responsible for the final step of energy generation.
In order for the process to occur, electrons must be passed between the complexes of the chain. The first complex accepts the electrons. Electrons are then moved to the third complex while protons cross the inner mitochondrial wall. In the third complex the electrons are joined with others donated from the second complex. Complex three then passes the electrons to complex four as more protons move across the inner mitochondrial membrane.
In the fourth complex, electrons are joined to oxygen which creates water, and protons cross the membrane once again. A gradient is created as a result of the movement of so many protons. This gradient is used to rotate the fifth complex, creating an adenosine triphosphate with every rotation.Learn More
The zona pellucida is the transparent, thick outer layer of the ovum in mammals that protects the cell as it travels from the ovary to the uterus. The National Institutes of Health states the layer regulates interactions between ovulated eggs and free-floating sperm as the egg is fertilized. In order to fertilize the egg, sperm must penetrate this outer layer as it thins on the way to the uterus.Full Answer >
Cell division, also called mitosis, occurs in multicellular organisms to create tissues, organs and organ systems. It is a method of asexual reproduction in unicellular organisms, and it occurs because it’s essential for increasing the population of the organisms.Full Answer >
Human skin cells contain 46 chromosomes, or 23 chromosome pairs, and after mitosis, the two daughter cells also have 46 chromosomes. Mitosis is a cellular process that creates two identical daughter cells from one original cell.Full Answer >
The consensus among biochemists is that virtually every cell in the human body can break down sugar, usually in the form of glucose, to use as energy. According to the authors of the 5th edition of "Biochemistry," the brain and the kidneys prefer to run on glucose. In fact, the brain favors glucose to such an extent that it only metabolizes other fuel sources after several days of starvation.Full Answer >