Chemicals Found in cells:

• Cells contain organic compounds and inorganic compounds. • Organic compounds contain carbon atoms combined with other atoms.

• Inorganic compounds do not necessarily contain carbon atoms. The main inorganic compounds found in cells are water, salts and oxygen.

• The main groups of organic compounds found in cells are
--> proteins
--> carbohydrates
--> lipids
--> nucleic acid

• Proteins contain the elements carbon, hydrogen, oxygen, nitrogen and sometimes phosphorous and sulfur. Proteins are used for the growth and repair of body tissues, and are present in hormones, cell membranes and enzymes. Enzymes are a vital cellular component, as they help to control all the chemical reactions that occur in the cell. Proteins are composed of chains of amino acids joined together by peptide bonds.

• Carbohydrates contain the elements carbon, hydrogen and oxygen, and are the major source of

proteins, carbohydrates, lipids, and

nucleic acids

energy for the cell. The form in which carbohydrates are used by the cell for respiration.

• Disaccharides such as sucrose are composed of two sugar units, and are often the form in which sugars are transported in the phloem cells of plants.

• Polysaccharides consist of many glucose units joined together, and are used as energy storage molecules. In plants, the polysaccharide starch is used to store energy, and in animals the polysaccharide glycogen is used as an energy storage molecule.

• Carbohydrates are also used to provide structural support; structural carbohydrates include cellulose, the main component of cell walls in plants, and chitin, which is found in the exoskeleton of insects and the cell walls of fungi.

• Lipids include oils, fats, steroids and waxes. As in carbohydrates, all lipids contain carbon, hydrogen and oxygen, but there is less oxygen in lipids.

• Fats consist of a glycerol molecule joined to three fatty acid groups, and are used to store energy. Oils are also used to store energy.

• Steroids are present in membranes and sex hormones, and waxes act as a waterproof layer in the leaves and fruits of plants.

• Nucleic acids contain a ribose or deoxyribose sugar, nitrogen bases and phosphate groups. They are the main component of DNA, the molecule responsible for heredity in all organisms, and RNA, which is involved in the manufacture of proteins.

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Apunte sobre A Local Ecosystem, creado por zoe98xoxo el 11/09/2013.