cells of the human body
Cells are the basic living units of all plants and animals. The cell is the structural and functional unit of all living organisms. There are a wide variety of cell types, such as nerve, muscle, bone, fat, and blood cells. Each cell type has many characteristics, which are important to the normal function of the body as a whole. One of the important reasons for maintaining hemostasis is to keep the trillions of cells that form the body functioning normally. An averaged size cell is one-fifth the size of the smallest dot you can make on a sheet of paper with a sharp pencil. Although cells may have quite different structures and functions, all cells share some common characteristics. The plasma, or cell membrane, forms the outer boundary of the cell through which the cells interacts with its external environment. The nucleus is usually located centrally and functions to direct cell activities, most of which take place in the cytoplasm, located between the plasma membrane and the nucleus. The plasma membrane is the outer part of a cell. The plasma membrane is made up of 45% - 50% lipids, 45% - 50% proteins, and 4% - 8% carbohydrates. The main lipids are phospholipids and cholesterol. Phosp
MITOCHONDRIA Mitochondria usually are small, rod-shaped structures. A complex series of mitochondrial enzymes forms two major enzyme systems that are responsible for oxidative metabolism and most ATP synthesis. All cells of the body have a nucleus at some point in their life cycle, although some cells, such as red blood cells, lose their nuclei as they develop. The fluid-mosaic model suggests that the plasma membrane is highly flexible and can change its shape and composition through time. For example, the normal process of bone remodeling involves the breakdown of bone tissue by specialized bone cells. DNA determines the structure of messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). When muscles enlarge as a result of exercise, the number of mitochondria within the muscle cells increases to provide the additional ATP required for muscle contraction. mRNA moves out of the nucleus through the nuclear pores into the cytoplasm, where it determines the structure of proteins. They provide mechanical strength to cells. Dust, minerals, and dyes can also accumulate in the cytoplasm. Small molecules or ions of the right shape, size, and charge can pass through the channel. G proteins may function in one of several ways. The Golgi apparatus concentrates and, in some cases, chemically modifies the proteins by synthesizing and attaching carbohydrate molecules to the proteins to form glycoproteins or attaching lipids to proteins to form lipoproteins. The ability of membrane proteins to function depends on their three-dimensional shape. Spindle fibers extend out in all directions from the centrosome.
Common topics in this essay:
CELL MEMBRANE,
CYTOSOL Cytosol,
ATP ATP,
ENDOPLASMIC RETICULUM,
SPINDLE FIBERS,
APPARATUS Golgi,
MITOCHONDRIA Mitochondria,
FLAGELLA Cilia,
LYSOSOMES Lysosomes,
,
plasma membrane,
endoplasmic reticulum,
golgi apparatus,
actin filaments,
cell division,
chemical reactions,
smooth endoplasmic,
lipid bilayer,
nm diameter,
smooth endoplasmic reticulum,
spindle fibers,
rough endoplasmic reticulum,
cell structure function,
red blood cells,
plasma membrane containing,
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Acceptance Essays
