Intro to Chemistry and Biology

• Study notes for BIOL-1101 Exam 1

Elements

• The simplest pure substances, comprising only one type of atom or molecule.
• Protons are positively charged atomic particles found in the nucleus.
• Electrons are negatively charged atomic particles orbiting the nucleus.
• Neutrons are neutral atomic particles located in the nucleus.
• Atomic number corresponds to the quantity of protons or electrons in an atom.
• Atomic mass equals the total count of protons and neutrons; values provided are mass averages.
• Isotopes feature variances in neutron count, impacting atomic mass though proton and electron counts are consistent.
• Unstable isotopes are radioactive, discharging energy or particles.

Electrons

• Electrons, negatively charged, orbit the atomic nucleus, balancing positive protons.
• Their mass is so negligible that it does not factor into calculations.
• The electron cloud is a construct with energy levels and orbitals.
• Energy levels are designated as K, L, M, etc.
• Orbitals are designated as S, P, D, F.
• Circular S orbitals at the K-level, having the lowest energy, support up to two electrons.
• L-level incorporates S and dumbbell-shaped P orbitals along the x, y, and z axes.
• Each P orbital contains up to 2e-, making total of 6e-
• Together, S and P orbitals at this highest shell can host a total of eight electrons.
• A valence electron is the outermost electron of an atom.
• Valence electrons participate in chemical reactions.
• Valence electrons determine the atom's reactivity.

Reactivity and Bonding

• Atoms seek a full valence shell, acquiring, relinquishing, or sharing electrons for stability.
• Ions are nonstable atoms exhibiting non-neutral charges.
• Cations are atoms that lose electrons and become positively charged.
• Anions are those that gain electrons, acquiring a negative charge.
• Ionic bonding involves one metal and one nonmetal exchanging electrons.
• Cations and anions combine to form a neutral compound.
• The magnitude of ionic charges influences the strength of the ionic bond, leading to polar bond development.
• Covalent bonding entails the sharing of electrons between two nonmetals.
• Covalent bonding produces three types of bonds; single (weakest), double (intermediate), and triple (strongest)
• The polarity of covalent bonds depends on the participating atoms.

Water's Properties

• Electronegative atoms strongly attract electrons.
• Halogens (F, Cl, Br, I) and Oxygen are electronegative atoms.
• Metals, toward the periodic table’s left, have the lowest electronegativity and readily lose electrons.
• Greater electronegativity disparities between atoms in a molecule result in a more polar molecule; water (H2O) is an example.
• Similar electronegativity results in less polar to no polar like H2 or F2
• Cohesion is the propensity of water molecules to bond with each other via hydrogen bonding.
• Cohesion generates surface tension, which surfactants can disrupt.
• Adhesion is the capability of water molecules to adhere to other polar and nonpolar molecules.
• An example of adhesion is water sticking to glass
• Water is often the universal solvent.
• Water is hydrophilic (water-loving) and dissolves ionic bonds.
• Nonpolar, water-repelling compounds are hydrophobic.

Water Reactions

• Dehydration synthesis occurs as molecules combine and release a water molecule.
• Hydrolysis occurs as complex molecules are broken apart with the addition of water.

pH, Acids, Bases, and Buffers

• The pH scale, ranging from 0-14, indicates acidity or alkalinity.
• A pH of 7 is neutral.
• The pH range of 0-6 is acidic.
• A pH above 7, ranging from 8-14, is basic or alkaline.
• Acids release H+ ions (protons) when dissolved in water, as seen in the example HCl = H(+) + Cl(-).
• Bases are a type of substance where OH− (hydroxide ions) absorb H+ ions, reducing acidity.
• Buffers counteract pH shifts with small quantities of added acids/bases.
• Buffers almost include a inclusion of a particular salt

Functional Groups

• Functional groups are specific groups of atoms with notable properties.
• The hydroxyl group is specified as R-OH.
• Hydroxl groups are bonded to a single OH and are found in alcohols like methanol/methylachohol.
• Carbonyl groups are designated as R-C=O, carbon double bonded to oxygen.
• Carbonyl groups are found in multiple compounds like Aldehydes, formaldehyde.
• Esters construct an "L" shape while ketones construct a "T" shape
• Carboxyl groups are a combination of hydroxyl and carbonyl groups.
• Carboxyl groups are found in organic acids like formic acid.
• Amino/Amine Groups are specified as NH2.
• Found in amino acids and acids (carboxyl group) + amine group; Simplest is glycine.

Macromolecules

• Primarily composed of carbon, oxygen, and hydrogen.
• Carbohydrates store energy in their C-H bonds.
• Monomers, or monosaccharides (aldehydes or ketones), are uncomplicated sugars in ring form with the suffix -ose.
• The number of carbons; pentose (5) and/or hexose (6).
• Monosaccharides merge into disaccharide polymers using dehydration synthesis.
• For instance, glucose can transform into various disaccharides.
• Alpha and beta forms of hexose are determined by the location of hydroxyl groups.
• Fructose is categorized as a ketone.
• Glucose and fructose form sucrose.
• When two glucose units bind, they form maltose.
• Connecting one unit of glucose with one of galactose forms lactose.
• Polysaccharides are longer and more complex carbohydrates.
• Alpha glucose creates a branched polymer.
• Starches and glycogen.
• Beta glucose is a polymer without branches like cellulose.

Lipids

• Composed of C, O, and H; store energy through C-H bonds in nonpolar and hydrophobic forms.
• Oils, fats, and waxes
• Triglycerides consist of glycerol and 3 fatty acids
• Cholesterol contains hormones created from saturated fats.
• Glucose becomes starch, with excess glucose from the liver being converted into triglycerides for storage.
• High Density Lipoprotein (HDL) serves as "Good" cholesterol.
• Low Density Lipoprotein (LDL) serves as "Bad" cholesterol.

Proteins

• Monomers are amino acids composed of amino and carboxyl groups; amine + organic acid.
• Monomers = amino acids
• Simplest = glycine
• Polypeptides named by # of amino acids being bonded together
• Ex: 2 amino acids bound by 1 peptide bond = dipeptide
• Primary sequence of amino acids
• Secondary
  • Primary sequences together in 3D space
  • Alpha helices
  • Beta pleated sheets
• Secondary structures folded back on each other,
• Globular proteins
• Enzymes
• Quaternary
  • Multiple tertiary structures together
  • Hemoglobin, hemocyanin
• Tertiary proteins catalyze reactions; The tertiary proteins have -ase endings. specific substrates bind to specific active sites that when when broken, break bonds and loose function.

Nucleic Acids

• The major components of nucleotide monomers are pentose sugar, phosphate group, and nitrogenous base.
• Nitrogenous bases contain purines with a 2 ring structure, comprising adenine and guanine as well as pyrimidines with 1 ring structure, comprising thyymine, cytosine and uracil
• DNA, Deoxyribonucleic Acid, is a double stranded helix using deoxyribose sugar and Thymine.
• RNA, Ribonucleic Acid , is single-stranded, in the form of a single strand using ribose sugar and uracil.

Test your knowledge of chemistry and biology with this quiz! Topics covered encompass acids, bases, functional groups, and properties of water, all fundamental to understanding biological processes.