NLN-PAX Science Rated A+

NLN-PAX Science Rated A+ Cell the smallest living unit and the basic unit of function and structure for all living things. Nucleus contains the genetic information, or DNA, and controls the activities of the cell. Plasma (cell) membrane separates the contents of the cell from the surrounding fluid (interstitial fluid) Semipermeable membrane refers to the selective nature of the plasma membrane. It contains pores and channels that allow only particles of the right size or the right chemical nature to pass through. Interstitial fluide contains substances such as amino acids, sugars, fatty acids, hormones, neurotransmitters, and salts. Cytoplasm is the fluid matrix found between the plasma membrane and the nucleus that acts as scaffolding for the organelles. Organelles (little organs) are specialized units in the cell that per form certain functions. Mitochondria are the locations for cellular respiration, that is, the conversion of food to energy at the cellular level. The site of energy production and of most of its ATP. ATP (adenosine triphosphate) the chemical the cell uses to store and transfer energy within itself. Ribosomes are the sites of protein synthesis in the cell Endoplasmic reticulum (ER) Ribosomes are attached. Serves as a means for transport within the cell and is made up of many channels. Rough endoplasmic reticulum named for the fact that it has ribosomes on its surface, serves to store and deliver the proteins made by the attached ribosomes. Smooth ER is free of ribosomes it performs varying functions in different cells, including the storage of enzymes and minerals and the folding of proteins, among other things. It is thought to be involved in the detoxification of chemicals and the metabolism of fats. Golgi complex modifies and packages proteins destined for use in the cell or for export from the cell. Lysosomes are sacs that contain strong digestive enzymes. These sacs are responsible for digesting cell structures that are no longer living or that are malfunctioning, and for digesting waste. Cell wall Only plant cells have them. It is responsible for the protection of the cell, the maintenance of the shape, and water balance. Chloroplasts contain chlorophyll, which is necessary for photosynthesis. Vacuoles plant cells also often large ones. Which are compartments in the cytoplasm that act as places for secretion, excretion, and storage. Chromatin DNA is in this loosely structured form when it is not dividing Chromosomes DNA is seen in condensed rod-shaped bodies when the cell is dividing Mitosis When cells divide, the appropriate amount of genetic material must be passed on to the new, or so-called daughter, cells. In somatic (non reproductive) cells, the new cells are identical copies of the parent cells. This is achieved by a doubling of the chromosomes prior to division. It is useful in the growth and repair of our bodies. Zygote the cell created by the union of a sperm and egg contains a full set of chromosomes, half from each parent. Meiosis Another type of division takes place in the production of gametes. It contains half of the normal number of chromosomes. It consists first of doubling of chromosomes and then two subsequent divisions. Thus the products are four daughter cells, each with half the normal number of chromosomes. Muscle tissue skeletal, cardiac, and smooth Epithelial tissue skin, the lining of organs Nervous tissue neurons Connective tissue cartilage, blood, fat, bone Organ performs a specialized function in the body. Organ system made up of a number of organs working together to carry out a major function.