Bio Notes PDF

Chapter 2 pt. 3 Molecular shape and function: Molecules are characterized by a specific shape and function Function depends on the shape- very important in cells Receptors and ligands ○ Shape can determine if they connect or not Antigens and antibodies ○ Antibodie...

Chapter 2 pt. 3 Molecular shape and function: Molecules are characterized by a specific shape and function Function depends on the shape- very important in cells Receptors and ligands ○ Shape can determine if they connect or not Antigens and antibodies ○ Antibodies fight to neutralize antigens Water: Polar molecule - with a V shape ○ Polar because Hydrogen is positive and oxygen is negative (opposites) Water molecules are held together by hydrogen bonds Good solvent Sugar dissolving in water-solution- solvent - solute ○ a aqueous solutions = water is the solvent ○ NaCl dissolving in water Hydrophilic = hydro (water) + Philios (loving) and eg (molecules like water) Hydrophobic = hydro + phobos (fearing) and eg - (repels water) Importance of Hydrogen Compounds Hydrogen is important because depending on the level will determine the PH which will impact the molecules ○ Acids Protons (hydrogen ion) donors, bases accept hydrogen ions. pH scale 7 is neutral ○ Anything above is more alkaline (baking soda, soapy water, ammonia cleanser) ○ Anything below is more acidic ( saliva, urine, black coffee) Chapter 2 pt.4 The chemistry of living things - Biological Molecules Biological Molecules: Each type of organic molecule has a unique three-dimensional shape that defines its function in an organism The molecules of your body recognize one another based on their SHAPE The unique properties of an organic compound depend not only on its carbon skeleton but also the atoms attached to the skeleton ○ Any molecule that has carbon in it will be called an organic molecule  These atoms are called function groups Hydroxyl groups- found in alcohols and sugars Carbonyl group- found in sugars Amino group- found in amino acids and urea in urine (from protein breakdown) Carboxyl group- found in amino acids, fatty acids, and some vitamins Giants Molecules from smaller building blocks: On a molecular scale, many of life's molecules are gigantic ○ Biologist call them macromolecules ○ Ex: DNA, carbohydrates Biological Macromolecules There are four categories of large molecules in cells: ○ Carbohydrates (Important functions - store energy, structural support) Small sugar molecules in soft drinks Long starch molecules in pasta and potatoes Types of carbohydrates: ○ Monosaccharides (one sugar) Glucose found in sports drinks Fructose found in fruit Honey contains both Monosaccharides are the main fuel that cells use for cellular work ○ Polysaccharides (50+ sugars) Complex carbohydrate Long chains of sugar units Starch (stores energy) found in plants Cellulose (structural support) found in plants ○ Most abundant organic compound on Earth ○ Major component in wood ○ Dietary fiber (clean you out) ○ Prokaryotes can break it down Glycogen (stores energy) found in animals ○ Oligosaccharides (three sugars) ○ Disaccharides (two sugars) Sucrose Sucrose is extracted from sugar cane and the roots of sugar beets ○ Lipids: Insoluble in Water (hydrophobic) Fats perform essential functions in the human body (insolation) Energy storage  Cushioning Insulation Types of lipids: Triglycerides: energy storage molecules (Glycerol + fatty acids) Phospholipids: Cell membranes Steroids: carbon-based ring structures: ○ Cholesterol: used in making estrogen and testosterone Triglycerides Most animal fats have a high proportion of saturated fatty acids- can be unhealthy ○ Ex. butter Most plant oils tend to be low in saturated fatty acids. ○ Ex. corn oil Not all fats are unhealthy ○ Some fats perform important functions in the body and are essential to a healthy diet Ex. omega 3 (fish) Phospholipids Structural component of a cell membrane One side is soluble (head) and another is insoluble in water (tail) Steroids Steroids are very different from fats in structure and function Cholesterol is the base steroid from which your body produces other steroid ○ Ex. sex hormones (testosterone, estrogen) Steroids are controversial- variants of testosterone ○ Athletes may use them but can have serious health risks ○ Proteins ○ Nucleic acids Average American consumes about 64 kg of sugar per year Good cholesterol and bad cholesterol: Chylomicron - high in triglyceride low in protein (bad) Low density lipoprotein- high in cholesterol, low protein (bad) High density lipoprotein - high protein and low in cholesterol (good) Lipid transport LDL “bad cholesterol” ○ Can lead to heart disease Cells get cholesterol from LDL ○ HDL is good cholesterol  High LDL is bad, high HDL is good ○ LDL level is higher with consumption of saturated fatty acids Chapter 2 pt. 5 Biological Macromolecules Proteins Made of amino acids ○ Set of 20 kinds of amino acids Each amino acid consist of ○ A central carbon atom bonded to four covalent partners ○ A side group that is variable among all 20 Amino group (left) Carboxyl group (right) side group (middle) Leucine (hydrophobic) Serine (hydrophilic ○ Of the 20 amino acids, our body can synthesize 11 ○ 9 are obtained from food (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine). Lysine and tryptophan are poorly represented in most plant proteins- problem for vegetarian ○ Your body has tens of thousands of different kinds of protein The arrangement of amino acids makes each one different Proteins: Complex Structures Constructed of Amino Acids ○ Structure Primary: amino acid sequence Secondary: describes chain orientation in space (ex. Alpha helix, beta sheet) Tertiary describes three-dimensional shape created by disulfide and hydrogen bonds Creates polar and nonpolar areas in molecule Quaternary: describes proteins in which two or more tertiary protein chains are associated Note: a slight change in the primary structure of a protein affects its ability to function The substitution of one amino acid for another in hemoglobin causes sickle cell disease. Red blood cells can move easily Sickle cell does not move as easily and can get stuck ○ Function Structural proteins Storage proteins Contractile proteins Transport proteins ○ Several biological functions  Enzymatic catalysis (rate chemical reaction) Transportation and storage: HB transport o2 in red blood cells and myoglobin in muscles; iron stored in liver as ferritin Coordinated motion: muscle contraction Mechanical support: collagen important for the skin and bone strength Other protein functions ○ Immune protection ○ Generation and transmission of nerve impulse ○ Control of growth and differentiation What determines protein structure ○ A protein shape is sensitive to the surrounding environment Unfavorable temperature and pH changes can cause a protein to unravel and lose its shape This is called denaturation Enzyme Function The functional shape of an enzyme is dependent on: ○ Temperature of reaction medium ○ pH ○ Ion concentration ○ Presence of inhibitors Nucleic acids: Function ○ Store genetic information ○ Provide information used in making proteins Structure ○ Nucleotides consist of a phosphate group, a sugar, and a nitrogen base ○ DNA structure is a double helix: two associated strands of nucleic acids ○ RNA is a single-stranded molecule Structure of DNA and RNA ○ DNA: double stranded Sugar: deoxyribose Nitrogenous bases: adenine, uracil, cytosine, guanine Pairing: adenine-uracil, cytosine-guanine ○ RNA: single stranded Sugar: ribose (extra OH group) Nitrogenous bases: adenine, uracil, cytosine, guanine Pairing: adenine-uracil, cytosine-guanine ○ ATP produces useful energy for the cell Come from food or body stored of glycogen or fat