Cell activities are controlled by whom?
Cell activities are controlled by whom?
The nucleus is the control center of the cell. A cell's nucleus is able to control the other activities in a cell by expressing certain segments of its DNA, which creates proteins that perform specific activities. Proteins can vary from enzymes to structural components, but they are needed for almost all processes in a cell and the human body.
The nucleus directs all cellular activities by controlling the synthesis of proteins. The nucleus contains encoded instructions for the synthesis of proteins in a helical molecule called deoxyribonucleic acid (DNA). The cell's DNA is packaged within the nucleus in a structural form called chromatin. Chromatin consists of DNA wound tightly around spherical proteins called histones. When the cell prepares to divide, the DNA unwinds from the histones and assumes the shape of chromosomes, the X-shaped structures visible within the nucleus prior to cell division. Chromatin packaging of DNA allows all of the cell's DNA to fit into the combined space of the nucleus. If DNA was not packaged into chromatin, it would spill out over a space about 100 times as large as the cell itself.
The first step in protein synthesis begins in the nucleus. Within the nucleus, DNA is translated into a molecule called messenger ribonucleic acid (mRNA). mRNA then leaves the nucleus through the nuclear pores. Once in the cytoplasm, mRNA attaches to ribosomes (either bound to endoplasmic reticulum or free in the cytoplasm) and initiates protein synthesis. Proteins made for export from the cell function as enzymes that participate in all the body's chemical reactions. Because enzymes are essential for all the body's chemical processes-from cellular respiration to digestion-direction of the synthesis of these enzymes in essence controls all the activities of the body. Therefore, the nucleus, which contains the instructions for the synthesis of these proteins, directs all cellular activities and thus all body processes.
The nucleus is the control center of the cell. A cell's nucleus is able to control the other activities in a cell by expressing certain segments of its DNA, which creates proteins that perform specific activities. Proteins can vary from enzymes to structural components, but they are needed for almost all processes in a cell and the human body.
The nucleus directs all cellular activities by controlling the synthesis of proteins. The nucleus contains encoded instructions for the synthesis of proteins in a helical molecule called deoxyribonucleic acid (DNA). The cell's DNA is packaged within the nucleus in a structural form called chromatin. Chromatin consists of DNA wound tightly around spherical proteins called histones. When the cell prepares to divide, the DNA unwinds from the histones and assumes the shape of chromosomes, the X-shaped structures visible within the nucleus prior to cell division. Chromatin packaging of DNA allows all of the cell's DNA to fit into the combined space of the nucleus. If DNA was not packaged into chromatin, it would spill out over a space about 100 times as large as the cell itself.
The first step in protein synthesis begins in the nucleus. Within the nucleus, DNA is translated into a molecule called messenger ribonucleic acid (mRNA). mRNA then leaves the nucleus through the nuclear pores. Once in the cytoplasm, mRNA attaches to ribosomes (either bound to endoplasmic reticulum or free in the cytoplasm) and initiates protein synthesis. Proteins made for export from the cell function as enzymes that participate in all the body's chemical reactions. Because enzymes are essential for all the body's chemical processes-from cellular respiration to digestion-direction of the synthesis of these enzymes in essence controls all the activities of the body. Therefore, the nucleus, which contains the instructions for the synthesis of these proteins, directs all cellular activities and thus all body processes.
