General Biology Study Notes

General Biology Study Notes

• Chemical elements: Four most common in living organisms are hydrogen, oxygen, nitrogen, and sodium.

• Fluoride addition: Fluoride is added to municipal water supplies to reduce tooth decay and prevent bacteria growth.

• Trace element in table salt: Iodine is a trace element commonly added to table salt.

• Boron atom neutrons: An uncharged boron atom with atomic number 5 and atomic mass 11 has 6 neutrons.

• Radioactive carbon isotopes: Radioactive isotopes of carbon undergo decay and contain more neutrons than protons.

• Radioactive isotopes uses: Radioactive isotopes can be used in conjunction with PET scans to diagnose diseases but are not typically added to food as nutritional supplements.

• Nitrogen electron shells: A nitrogen atom with atomic number 7 has an innermost electron shell that holds 2 electrons, and an outermost shell holding 5 electrons when full.

• Silicon valence electrons: A silicon atom has 4 valence electrons in its outer shell.

• Covalent vs ionic bonding: Covalent bonds form when partners share electron pairs, while ionic bonds form when one partner accepts electrons from the other.

• Nitrogen covalent bonds: A nitrogen atom can form three single covalent bonds.

• Lithium and chlorine bonding: Lithium donates its single outer electron to chlorine when LiCl forms.

• Medicine pill bonding: The active ingredient of a pill is often bonded to another stable substance via covalent bonds, forming a salt.

• Water molecule bonding: Hydrogen atoms in a water molecule are bonded to the oxygen atom with polar covalent bonds. Neighboring water molecules are held together by hydrogen bonds.

• Water molecules cohesion and adhesion: Cohesion is the tendency of water molecules to stick together; adhesion is the tendency of water to stick to other surfaces. Both are important in plant water transport.

• Chemical reactions & atoms: Chemical reactions involve the rearrangement of atoms, with the same number of each element on both sides of the equation.

• Balanced equation: H3PO4 + 3KOH → K3PO4 + 3H2O is a balanced chemical equation.

• Water properties: Water's polarity allows it to dissolve various substances, including many important biological molecules.

• Hydrogen bonds & water temperature moderation: Hydrogen bonds allow water to absorb and release heat slowly, moderating temperature changes.

• Water as a solvent: Water's polarity enables it to dissolve many substances, making it a versatile solvent.

• Polar and nonpolar substances: Polar substances dissolve in water, while nonpolar substances do not.

• pH scale: The pH scale measures the hydrogen ion concentration, and an increase in hydrogen ion concentration leads to a decrease in pH (more acidic).

• Aqueous solutions: Bases release hydroxide ions (OH-) into an aqueous solution, increasing the pH (decreasing acidity).

• Ocean acidification: Dissolving CO2 in the ocean lowers the pH.

• Coral reefs and acidification: Coral reefs grow slower due to lower carbonate ion availability with increasing ocean acidity.

• Isomers: Isomers have the same molecular formula but different chemical properties.

• Functional groups: Functional groups, which contain carbon atoms, make organic compounds hydrophilic and participate in chemical reactions.

• Octe and covalent bonds: Octane's covalent bonds are formed by carbon and hydrogen with similar electronegativities, making them nonpolar.

• Hydrolysis & dehydration: Hydrolysis breaks down polymers into monomers using water, while dehydration forms monomers into polymers by releasing water.

• Monosaccharides: Monosaccharides have a molecular formula that represents multiples of CH2O.

• Glucose: Glucose is a monosaccharide, a primary source of energy for cells.

• Polysaccharides Structure Chitin is a structural polysaccharide found in exoskeletons and cell walls of fungi, while Glycogen is a storage polysaccharide found in animal tissues.

• Cell structure: Mitochondria and chloroplasts are involved in energy transformations; however, only chloroplasts are responsible for photosynthesis and are not found in animals.

• Microtubules and Microfilaments: Microtubules, which are composed of tubulin, are thicker and are a part of the protective structure of cells; microfilaments are made of actin and play a role in cell shape and movement.

• Mitochondria and DNA: Mitochondria contain their own DNA.

• Sperm motility and dynein: Sperm motility depends on dynein, which is a protein essential for flagellar movement.

• Cell junctions: Tight junctions prevent fluid leakage between cells in the intestinal linings.

• Plant cell walls: Plant cells have a cell wall, made primarily of cellulose, providing support for the structure.