The nucleus is the control center of a cell. The nucleus controls the cell's growth and reproduction and contains the cell's DNA.Know More
The nucleus of a cell contains most of that cell's genetic material. Its job is to maintain the integrity of the cell while controlling its activities. The nucleus is separated from the cytoplasm by a membrane called a nuclear envelope.This helps to protect the cell's chromosomes which is where the DNA is located.
The nucleus was first discovered by microscopist Antonie van Leeuwenhoek in the mid-1600s while he was examining the red blood cells of salmon. The nucleus was again observed in 1804 by Franz Bauer and botanist Robert Brown, who described the nucleus in great detail in 1831.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 >