Human+Bio+HW2+MC

2.3 Molecules of Life (pg.27) •	Organic Molecules are types of molecules that contain carbon and hydrogen and often contains oxygen too. 1.	What are the four classes of molecules unique to cells? The four classes of molecules unique to cells are carbohydrates, lipids, proteins, and nucleic acids. 2.	2. What type of reaction occurs during the synthesis of macromolecules? A dehydration reaction occurs during the synthesis of macromolecules. 2.4 Carbohydrates (pg.28-29) •	A monosaccharide is a simple sugar and a carbohydrate that cannot be decomposed by hydrolysis. •	A disaccharide is a sugar that contains two units of a monosaccharide. •	A glucose is a six-carbon sugar that organisms degrade as a source of energy during cellular respiration. •	A polysaccharide is a polymer made from sugar monomers. •	A starch is storaged polysaccharide found in plants that is composed of glucose molecules joined in a linear fashion with a few side chains. •	A glycogen is a storaged polysaccharide that is composed of glucose molecules joined in a linear fashion but having numerous branches. •	Cellulose is a polysaccharide that is the major complex carbohydrate in plant cell walls. 1.	What is the usual function of carbohydrates in humans? It functions for quick and short-term energy storage in humans. 2.	What is the difference between a simple carbohydrate and the various complex carbohydrates? A simple carbohydrates means that the number of carbon atoms is low and a complex carbohydrate are polysaccharides that contain many glucose units. 3.	Of what benefit is fiber in our diet? If you have high-fiber in your diet you will have a low incidence of heart disease and cancer. 2.5 Lipids 1.	Define saturated fats, unsaturated fat, and trans fat. Saturated fats have no double bonds between the carbon atoms. Unsaturated fat have double bonds in the carbon chain wherever the number of hydrogens is less than two per carbon. Trans fat is vegetable oils that have been partially hydrogenated to make them semi-solid. 2.	What is the main function of fats and oils and what are they composed of? Fat is used for long-term energy storage, it insulates against heat loss, and it forms a protective cushion around major organs. Oils have been found to be protective against cardiovascular disease. They are composed of one glycerol molecule reacting with 3 fatty acid molecules. 3.	What are the uses of phospholipids and steroids in the body? Phospholipids are the primary components of cellular membranes and they form a bilayer in which the hydrophilic heads face outward toward watery solutions and the tails form the hydrophilic interior. Steriods produce estrogen in females and testosterones in males to have a profound effect on the body. 2.6	Proteins (pg. 32-34) •	Peptide Bond is the resulting covalent bond between 2 amino acids. A denaturation is a process being an inversible change in shape. 1.	What are the major functions of proteins in an organism? Proteins make up hair and nails and collagen, lending support to ligaments, tendons and skin. Enzymes speed up reactions. Channel and carrier proteins in the plasma membrane allow substances to enter and exit cells. It transports oxygen. They prevent antigens from destroying cells and upsetting homeostasis. They serve as intercellular messengers that influence the metabolism of cells. They also allow parts of cells to move and cause muscles to contract. 2.	How does an amino acid get its name? One of the groups is an NH2 (amino group) and another is a COOH (an acid group). The third group is the R group for an amino acid. 3.	How does the shape of a protein relate to its function. Proteins cannot function unless they have their usual shape. When proteins are exposed to extremes in heat and pH, they undergo an irreversible change in shape called denaturation.