Bioap Ch.1 Study Guide

Bio- Mega Study Guide: Chap. 1 3.1 to 3.2: -A water molecule is made of two hydrogens joined with an oxygen through single covalent bonds. -The charge of oxygen is partial negative, while the charge of hydrogen is partial positive. -The opposite ends of a polar molecule ELECTRONEGATIVITY: O-N-C-H (from strongest to weakest. remember in this order.) Life-Sustaining Properties of Water: 1) Cohesion: Water sticks to itself. -Water is held by very fragile hydrogen bonds. However, because they are so weak, the hydrogen bonds can break and reform all the time. 2) Adhesion: Water sticks to something else. �Capillary action.� 3) High Surface Tension: -Surface tension is the difficulty of breaking the surface of a liquid. 4) Water can moderate the temperature by absorbing or releasing heat. It absorbs heat from warm air and releases the stored heat to cool air. When two objects of different temp. are brought together, heat passes from the warmer object to the cooler one until both have the same temp. For instance, an ice cube makes the drink cooler by sucking heat from it. 5) Water�s High Specific Heat: (high HEAT CAPACITY) -Specific heat= how well a substance resists temperature change when it gains or loses heat -Spec. heat of water= 1 cal/1 g/ 1� C. -Means that water will not have to change its temperature as much when it gains/loses heat. - Because of water�s high spec. heat, oceans� temperatures don�t change a lot (permits life) 6) Ice floats on water. -water is less dense as a solid than as a liquid. Therefore, ice (solid form) floats in water. At 0�C, water molecules are frozen and cannot break the hydrogen bonds. -if ice sank, then all the lakes and seas would freeze Evaporative Cooling: -as a liquid evaporates, the surface of the liquid that remains behind cools down. -the hottest molecules leave and become gas molecules, while the ones left behind can cool down. -evaporative cooling helps keep temperatures stable. -Hydration shell: the sphere of water molecules around each dissolved ion. Example: a salt crystal is put in water. The H+ of the water is attracted to the chloride ions (which are negative), and the Oxygen is attracted to the Na+. __________________________________________ Organic Molecules: -Organic molecules have carbon atoms. Polymers are molecules that are made of a sequence (repeated many times) of monomers. -Condensation/dehydration reaction: a water molecule is lost to put two monomers together. One monomer loses an OH-, and the other loses an H+. -Hydrolysis: Water added to take apart the monomers. Carbohydrates: -monosaccharides, disaccharides, and polysaccharides. -location of �carbonyl� group (the C=O) determines whether the sugar is an aldose

or a ketose. (note: carbonyl group at top branch= aldose; at side/middle branch= ketose). -Hexose= a 6-carbon sugar (ex: glucose, fructose, etc.) -Disaccharides= formed from a glycosidic linkage (�glyco�=glucose/sugar); which is a covalent bond formed between two monosaccharides through a dehydration reaction. -most common disaccharide: sucrose (=glucose+fructose) -Polysaccharides can either serve for storage or structure. (think starch, glycogen, cellulose, and chitin). -simplest form of starch is amylose, which has no branching. -plants store starch in cell parts called �plastids�. Synthesizing starch allows the plant to store extra glucose. If the plant needs more glucose, the glucose monomers can be broken off from the starch through hydrolysis. -most abundant compound on Earth= cellulose. -Chitin: can also be found in cell walls of fungi -We are unable to digest cellulose because our enzymes can�t hydrolyze the �linkages of cellulose. *The shapes of the enzymes don�t match the shape of the cellulose. -Glycogen: energy storage for animals; hydrolysis of glyco. releases glucose.

Lipids: Fats: -not polymers, but they are macromolecules -glycerol + 3 fatty acids -the nonpolar C-H bonds of the fatty acids make fats hydrophobic -Saturated fatty acids are STRAIGHT and SOLID at room temperature (they don�t have the �cis,� or double bond between carbon atoms and therefore are not bent) -Unsaturated fatty acids have the bend, and the carbon atoms are not so tightly packed (reason why unsaturated fats are not solid at room temp.) Phospholipid: -glycerol + 2 fatty acids -hydrophilic head (because of phosphate group) and two hydrophobic tails Steroids: -A steroid is made of 4 linked carbon rings. -Examples of steroids are cholesterol and hormones. ____________________________________________________________ Proteins: -most important type of protein= the enzyme. -enzymes work as catalysts, or agents that speed up reactions without being consumed -monomers are amino acids. 1) Primary structure: describes the sequence of amino acids. 2) Secondary structure: made of hydrogen bonding. Alpha helix: has a hydrogen bond between every fourth amino acid. Keratin has mostly alpha helixes. Beta pleated sheets: dominate the structures of globular and fibrous proteins.

3) Tertiary structure: made of hydrogen, disulfide, and ionic bonds. 4) Quarternary: aggregation of all the chains. CLARIFICATION: Amino acids -� polypeptide chains (or just polypeptides) � proteins -a protein is made of one or more polypeptides that conformations. -denaturation: the unraveling of a protein�s shape; *Factors such as the transfer of the protein from a organic solvent, high temperature, and change in pH

are folded into specific makes it inactive watery environment to an can cause denaturation

*The sequence of amino acids determines protein conformation (shape)!!!!!!! -chaperonins: are protein molecules that assist the folding of other proteins ____________________________________________________________ Nucleic Acids: -nucleic acids are polynucleotides. A nucleotide (the monomer) is made of a base, a pentose sugar, and a phosphate. -the part of the nucleotide without the phosphate group is called a nucleoside -two types of nitrogenous bases= pyramidines and purines -A pyramidine has a six-membered ring of carbon and nitrogen atoms. *The pyramidines are Cytosine, Uracil, and Thymine (REMEMBER: PYRAMIDS CUT). - A purine is larger, with a six-membered ring attached to a five-membered ring. *The double helix has an antiparallel structure. The two sugar-phosphate backbones run in opposite 5� to 3� directions from each other. *The 5� end has a phosphate group. ATP and How It Works: