The roller coaster car has a speed of 15 ft>s when it is at the crest of a vertical parabolic track. Determine the cars velocity and the normal force it exerts on the track when it reaches point B. Neglect friction and the mass of the wheels. The total weight of the car and the passengers is 350 lb.
Biology CH 1, 2 Genome: set of all genes in a cell Proteome: set of all proteins in a cell Discovery approach: collecting data with no hypothesis, then creating a hypothesis after collecting the data Hypothesis approach: developing a hypothesis, then conducting experiences based on that hypothesis Scientific Method CF gene (defective chloride gene): researchers used the discovery approach, didn’t know what to expect Hypothesis: tentative explanation Theory: tested with evidence, best explanation, not just an idea Law: not a better theory, a relationship that has been observed over and over Fact: not just an explanation, a single indisputable piece of information Everything that in a cell is a molecule Earth= 4 billion years’ old Everything follows the rules of chemistry and physics All elements want 8 electrons in their outer shell All elements have an ID- their atomic number, or number of protons Number of neutrons and electrons can change, and it can stay they same element If the number of protons change, it will no longer be the same element Period: group of atoms that have the same number of electrons in its outer shell Group: group of atoms that have the same number of shells Valence electrons: the electrons in the outer shell Biology: the study of life Angiotensin-converting enzyme(ACE) inhibitor: derivatives of a chemical, found in the venom of the arrowhead viper and used to treat high blood pressure Elements with almost 8 valence electrons are electronegative How an atom behaves depends on its number of valence electrons Bonds hold atoms together Types of bonds: polar covalent and nonpolar covalent Bonds: forces of attraction Examples of molecules that are covalent: h2o, co2, o2, glucose, ATP, chlorophyll, adrenaline 2 Ionic bond: transfers valence electrons Covalent bond: shares electrons Ionic bonds aren’t strong in biology because they are extremely soluble in water Polar covalent: has an unbalanced charge (partial negative charge) Nonpolar covalent: share electrons equally (no partial charge) CH is covalent- nonpolar because they both have low electronegativity Ionic bonds: ions attract (gains or looses 1 or more electron) Cations: positive Anions: negative Electronegative elements: oxygen, nitrogen, phosphorus, sulfur Polar: hydrophilic: dissolves in water Nonpolar: hydrophobic: hates water (ex. oil) Nonpolar covalent have similar electronegative Hydrogen bond is like Velcro (a few aren’t strong, but a lot are Solution: solutes in a solvent Amphipathic: both at the same time Water has a high heat of vaporization and evaporative cooling Cohesion: sticks to itself Adhesion: sticks to others 3 Transpiration: evaporation from leaf Chapter 3 Nutrients are molecules Organic molecule: carbon + hydrogen Carbon fixation: converts CO2 to organic molecules Carbohydrates, lipids, proteins, and nucleic acid Carbon has 4 valence electrons Functional groups H Amino: -NH2 R----N Amino acids(proteins) H Weakly basic (can accept H+); polar; forms part of peptide bonds Carbonyl Ketone: (-CO) O Steroids, waxes, and R-----C-----R proteins Polar; highly chemically reactive; forms hydrogen bonds Aldehyde: O Linear forms of sugar and some odor R----C----H molecules Polar; highly chemically reactive; forms hydrogen bonds Carboxyl: (-COOH) Amino acids, fatty acids 4 Acidic(gives up H+ in water); forms part of peptide bonds O R----C OH Hydroxyl: (-OH) R----OH Steroids, alcohol, carbohydrates, Some amino acids Polar; forms hydrogen bonds with water Methyl: (-CH3) May be attached to DNA, proteins and carbs; nonpolar H R-----C-----H H Phosphate: (-PO4) Nucleic acids, ATP, phospholipids Polar; weakly acidic and thus negatively charged at typical pH of living organisms O R-----O-----P------O O Sulfate: (-SO4) May be attached to carbohydrates, proteins and lipids Polar; negatively charged at typical pH O 5 R-----O-----S------O O Sulfhydryl: (-SH) R-----SH Proteins that contain the amino acid cysteine Polar; forms disulfide bridges in many proteins Isomers: 2 molecules with different structures and characteristics Structural isomers: same molecule, different place (attached to a different atom, same element within the group) Stereoisomers: 2 types: cis and trans Cis isomers: form a “C” Trans isomers: form a chair Enantiomers: mirror image of another group Macromolecules: polymers built from monomers Polymer: many monomers “chained” together Dehydration synthesis: lets go of water when it bonds; covalent Hydrolysis synthesis: adds a water when it breaks apart Transcription- RNA Dehydration is catalyzed by enzymes Polysaccharides of glucose: starch, glycogen, and cellulose Lipids 6 Not a polymer All are hydrophobic and nonpolar Steroids have 4 rings Fats AKA triglycerides Carboxylic acid Fatty acids Saturated and unsaturated Margarine: partially hydrated vegetable oil Steroids: Ex. cholesterol Higher electronegativity Periodic Table Lower electronegativity + charge = cation - charge= anion covalent bonds C----H nonpolar O---O nonpolar O, P,N,F polar Nonmetal+ metal= ionic Atomic number: number of protons Atomic mass: number of neutrons+ protons; mass 7 8