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Chapter 1 - The Study of Life

• The five fundamental characteristics of life include cells, replication, information, energy, and evolution.
• Pasteur's experiments demonstrated that life originates from pre-existing life, disproving spontaneous generation.
• In Pasteur's experiment, cells would appear in both flasks if the nutrient-rich broth was warmed instead of boiled.
• The structure of DNA is useful because it shows how genetic information is stored, copied, and passed to subsequent generations.
• The genetic code provides evidence for the common ancestry of all life.
• If a hypothesis is correct, certain test results can be expected.
• Hypotheses are usually relatively narrow in scope, whereas theories possess broad explanatory power.
• Stating a hypothesis and using that hypothesis to make a testable prediction is what one does when using a battery to jump-start a car.
• To run a controlled experiment on ant navigation, all variables except leg length were held constant for the test group of 75 ants.
• Theories usually explain a more general phenomenon; hypotheses typically address more specific issues.
• The genetic information of each cell is copied and passed on to daughter cells.
• Molecular machinery makes copies of particular genes in different cells to generate different features.
• Spontaneous generation refers to the idea that life could arise from nonliving matter.

Chapter 2 - Water and Carbon: The Chemical Basis of Life

• About 25 natural elements are essential to life; 4 of these make up 96% of living matter.
• The number of protons in its nucleus makes each element unique with respect to its chemical properties.
• Some carbon atoms in nature have more neutrons which is why the average atomic mass of carbon found on a periodic table is slightly more than 12 daltons
• A phosphorus atom has 15 protons due to its atomic number being 15.
• A covalent chemical bond involves the sharing of outer shell electrons by two atoms to fill their outer electron shells.
• In ammonia (NH3), each hydrogen atom has a partial positive charge, while the nitrogen atom has a partial negative charge because nitrogen is more electronegative than hydrogen..
• Nonpolar covalent bonds form between two atoms with equal electronegativity.
• Two electrons are involved in a single covalent bond.
• Elements found on the left side of the periodic table contain almost empty outer shells and form cations in solution.
• An atom with four electrons in its valence shell can form single, double, or triple covalent bonds.
• A molecular formula indicates a molecule's type and number of atoms like H20 which means that a water molecule contains 2 hydrogen atoms and 1 oxygen atom.
• A space-filling model illustrates the relative sizes of atoms and their spatial relationships in a molecule.
• The chemical versatility of carbon atoms accounts for the complexity and variety of organic molecules.
• The carboxyl group (COOH) acts most like an acid in water.
• Compounds containing both hydroxyl and carboxyl functional groups are most likely to behave in a polar manner.
• Stanley Miller's 1953 experiments supported the hypothesis that organic molecules can synthesize abiotically under conditions that may have existed on early Earth.
• Liquid water possesses a higher heat of vaporization than most other substances.
• A solution with a pH of 5 has 100 times more protons than a solution with a pH of 7.
• A neutral solution has a pH of 7 with 0.0000001 (10-7) moles of hydroxyl ions [OH-] per liter.
• Hydrocarbons are insoluble in water because the majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.
• Chemical reactions tend to be spontaneous when the reactants are more ordered than the products.
• Forward and reverse reactions continue at chemical equilibrium with no effect on the concentrations of the reactants and products.
• Hydrogen bonds must be broken to vaporize water.
• Adding an ice cube to a drink decreases the kinetic energy in the drink.

Chapter 3 - Proteins

• A phosphorus atom is not a component of each monomer used to make proteins.
• The R group varies across different amino acids.
• At pH 7, the amino group on an amino acid gains a proton and becomes positively charged.
• The carboxyl group on an amino acid will be deprotonated at pH 7.
• A peptide bond is a covalent bond formed between the carboxyl group of amino acid 1 and the amino group of amino acid 2.
• Bonding of two amino acid molecules to form a larger molecule requires releasing a water molecule.
• Twenty different amino acids exist, and each has a unique "side chain" or "R group".
• Carboxyl and amino groups are always found in amino acids.
• Hydrogen bonding stabilizes the a-helix and the β-pleated sheet structures of proteins.
• The shape of a protein shaped like a doughnut is a function of the tertiary structure.
• Van der Waals interactions stabilize hydrophobic side chains congregated together as a protein folds in an aqueous solution.
• The three-dimensional shape of a protein molecule is its tertiary structure.
• Interactions between side chains (R-groups) are most important at the tertiary level of protein structure.
• Changing a single amino acid in a protein consisting of 325 amino acids would always alter the primary structure of the protein.
• The structural level of a protein LEAST affected by a disruption in hydrogen bonding is the primary structure.
• The a-helix and the β-pleated sheet represent secondary protein structure.
• Denatured (unfolded) proteins do not function normally, which provides the strongest evidence that protein structure and function are correlated.
• A fever becomes harmful if it rises because it denatures proteins, disrupting their essential functions.
• Enzymes that catalyze reactions are proteins in biological systems.
• Energy storage that can be easily digested and metabolized is NOT a potential function of proteins.
• Secondary and tertiary structures of proteins contribute to their ability to catalyze reactions by allowing molecules to be precisely oriented.

Chapter 4 - Nucleic Acids

• Nucleic acids are polymers made up of nucleotide monomers.
• Ribonucleotides have a hydroxyl group on the 2 carbon on their sugar subunit where deoxyribonucleotides do not.
• A nitrogenous base, a pentose sugar, and a phosphate group are variable structures of a nucleotide.
• Cytosine, Uracil, and Thymine include all of the pyrimidines found in RNA and DNA.
• Guanine and adenine are purine nitrogenous bases.
• Phosphate groups provide the energy for polymerization when nucleic acids are formed.
• DNA's secondary structure is best described as double antiparallel helical strands.
• A double-stranded DNA molecule with 120 purines and 120 pyrimidines is composed of 120 adenine and 120 thymine molecules.
• Histones are large proteins that DNA typically wraps around, forming the tertiary structure of DNA.
• A nucleotide comprises a nitrogenous base, a phosphate group, and a sugar (a pentose)
• If a segment of double-stranded DNA has a guanine content of 28%, the adenine content would be 22%.
• The complementary DNA strand to 5'-GGCCAAAT – 3' is 3' - CCGGTTAA - 5'
• In DNA, Adenine (A) pairs with Thymine (T) and Cytosine (C) pairs with Guanine (G).

Chapter 5 - Carbohydrates

• Varying among monosaccharides is the number of carbon atoms they contain.
• The position of the carbonyl group distinguishes an aldose sugar from a ketose sugar.
• A molecule with the chemical formula C6H12O6 is likely a monosaccharide (specifically, glucose).
• Glycogen is significantly more branched than starch, making it a more readily accessible energy storage molecule for animals.
• A glycosidic linkage in carbohydrates is analogous to a peptide bond in proteins.
• Chitin is an important polysaccharide found in both animal exoskeletons and fungal cell walls.
• Lactose, contains one glucose and one galactose molecule and so is classified as a disaccharide.
• Cellulose is a complex carbohydrate found in plant cell walls, acting as a structural component that gives plants their rigidity.
• Glucose is a carbohydrate monomer, not a polymer.
• Starch should be expected to be most soluble in water.