Barrons SAT Biology - Chapter 4 Biochemistry
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Created by:
cjmnksa Plus on November 26, 2010
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barrons sat biology biochemistry chapter 4
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47 terms
Terms | Definitions |
|---|---|
 Six characteristics of water | 1. High specific heat 2. High heat of evaporation 3. High adhesion properties 4. Universal solvent of all polar and ionic substances 5. Strong cohesion tension - molecules stick together 6. Ice floats - water is more dense |
| Covalent bonds are two types | Nonpolar covalent - balanced. Electrons are shared equally by same atoms. H+H=H₂ Polar covalent - unbalanced. Electrons are shared unequally by different atoms. H₂O O⁻ / \ H⁺ H⁺ |
| Polar-Polar Attraction | Strong attraction between molecules of a polar bond. The negative end of one polar bond strongly attracts the positive end of another polar bond. H₂O is highly polar. |
| Hydrogen Bonding Two important hydrogen bonding functions are... | 1. Keeps the two strands of DNA bonded together, forming a double helix 2. Causes water molecules to stick together O⁻ O⁻ / \ / \ H⁺ H⁺ H⁺ H⁺ . . . . . . O⁻ / \ H⁺ H⁺ |
| Nonpolar Molecules | Have the weakest attractions, called van der Waals. Ex: CO₂ O=C=O shares double nonpolar bonds and is very balanced. |
| pH | The measure of acidity and alkalinity of a solution. Less than 7 is acidic, greater than 7 is alkaline, or basic. 7 is neutral. |
| pH of stomach acid | 2 |
| pH of milk | 6.5 |
| pH of blood | 7.4 |
| internal pH of most living cells | close to 7 |
| How is pH regulated in the body | Buffers - they absorb excess and give needed hydrogen ions for a pH 7 balance |
| Most important buffer in human blood | bicarbonate ion - HCO₃⁻ |
| Organic compounds. Name the four types | Organic compounds are compounds that contain carbon. Carbohydrates, lipids, proteins, nucleic acids |
| Carbohydrates consist of what three elements | carbon, hydrogen, oxygen. |
| Name the three important details of carbohydrates and name the three classes | 1. Supply quick energy 2. one gram of carbs will release 4 calories when burned 3. dietary sources are starches 4. three classes: monosaccharides, disaccharides, polysaccharides |
| Monosaccharides |  Have chemical formula of C₆H₁₂O₆. Examples are glucose, galactose, and fructose which are all isomers of each other but have different physical and chemical properties. Image: structural formula of glucose |
| Disaccharides |  C₁₂H₂₂O₁₁ - Consist of two monosaccharides joined by a process called dehydration synthesis. |
| Dehydration Synthesis | Process where water is removed to put two smaller molecules together. Monosaccharide+Monosaccharide=Disaccharide and water C₆H₁₂O₆ + C₆H₁₂O₆ = C₁₂H₂₂O₁₁ and H₂O Examples: Glucose+Glucose=Maltose+Water Glucose+Galactose=Lactose+Water Glucose+Fructose=Sucrose+Water |
| Hydrolysis | The breakdown of a compound. it occurs during digestion and is the reverse of dehydration synthesis. Sucrose + Water -> Glucose + Fructose |
| Polysaccharides | Polymers of carbohydrates. They are formed by many monosaccharides joined together by dehydration synthesis. |
| Four important Polysaccharides - 2 in Plants and 2 in Animals | Found in plants: cellulose and starch Found in animals: chitin and glycogen |
| Cellulose | A polysaccharide that makes up plant cell walls |
| Starch | A polysaccharide - the way plants store carbohydrates |
| Chitin | makes up the exoskeleten in anthropods and cell walls of mushrooms |
| Glycogen | A polysaccharide - "Animal starch"; in humans this is stored in the liver and skeletal muscle |
| Lipids are... | Fats, oils and waxes. Structurally, most consist of one glycerol and three fatty acids. |
| Glycerol |  An alcohol. It bonds with 3 fatty acids to form a lipid. |
| Fatty Acids (describe structure and give the two types) | A fatty acid chain is a hydrocarbon chain with a carboxyl group (COOH) at one end. Types are saturated and unsaturated |
| Saturated Fatty Acids |  Mostly from animals. Solid at room temps; linked to heart disease. Saturated fatty acids contain only single bonds between atoms and have a carboxyl group (COOH) on the end. |
| Unsaturated Fatty Acids |  Extracted from plants; liquid at room temps; considered good dietary fats; have at least one double bond between carbon atoms in the hydrocarbon chain so they have fewer hydrogen atoms, and have a carboxyl group (COOH) on the end. |
| Lipids - 3 Functions | 1. Energy storage - 1 gram of lipid releases 9 calories of energy 2. Structural - Phospholipids are a major component of the cell membrane 3. Endocrine- Some are hormones |
| Proteins are... | Polymers or polypeptides consisting of amino acids joined by peptide bonds. They consist of the elements SPCOHN. |
| Characteristics of Proteins | 1. Responsible for growth and repair. 2. Dietary sources are animal foods and plants (beans, nuts). 3. One gram burned in caloriemeter releases 4 calories. 4. Enzymes are proteins |
| Amino Acids |  The building blocks of protein. There are 20 different amino acids. Humans produce 10. The others are supplied by food. Amino acids consist of a carboxyl group, an anime group, and a variable (R), all attached to a central atom. The R group differs with each amino acid |
| Peptide bond |  covalent bond formed between amino acids. |
| Protein Structure - name the four levels |  Primary - the sequence of amino acids in the chain Secondary - the hydrogen bonding within the molecule Tertiary - the 3D shape - this determines how it functions. When a protein/enzyme denatures from high heat or adverse pH its tertiary structure is altered and cannot be repaired so it cannot function. Quaternary - proteins that consist of more than one polypeptide chain. EG - Hemoglobin is quaternary because it has four chains |
| Enzymes |  Large proteins that regulate metabolism by acting as catalysts. They speed up reactions by lowering the energy of activation (Ea); They are reused and not degraded. They work on chemicals called substrates. and are specific so they alter their shape for substrate to fit. |
| Naming enzymes | Named after their substrate with -ase suffix. Eg: Enzyme hydrolizes sucrose is sucrase; Enzyme that hydrolyzes lactose is lactase (necessary for digestion of dairy) |
| Enzymes function with the assistance of ... | cofactors (minerals) or coenzymes (vitamins) |
| Enzymes and temperature |  If body temp rises above 40C enzymes will stop functioning |
| Enzymes and pH |  Each enzyme has an optimal pH. Some acidic, some alkaline. Each are at optimal pH in he middle of their range. Gastric enzyme - active at low pH when mixed with stomach acid. Intestinal enzyme amylase active in alkaline (high) pH |
| pH compared with Molarity | A solution of pH 1 is 10 times more acidic than one of pH 2, 100 times more than pH 3, 1000 times more than pH4. Each pH value increases by 10. |
| Nucleic Acids | DNA - deoxyribonucleic acid and RNA - ribonucleic acid. They carry hereditary information. |
| Describe nucleic acids | They are polymers (chains of repeating units) of nucleotides. A single nucleotide consists of a phosphate, a 5-carbon sugar (either deoxyribose or ribose) and a nitrogen base. |
| The bases of DNA are... |  adenine, cytosine, guanine, and thymine |
| The bases of RNA are... | adenine, cytosine, guanine, and uracil |
| Prions | Infectious proteins that cause disease. it is a misfolded version of a protein normally found in the brains of mammals. If it gets into a normal brain it causes all normal proteins to misfold in the same way. |
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