(A) Cohesion and Adhesion: Two Properties of Water COHESIVE force are STRONG enough to cause water to have a thin “SKIN” on its surface. NOTE: ADHESION is force between UNLIKE substances (Ex: Water holding TWO glass microscope slides together)
(1) The SURFACE TENSION of water at room temperature is so great that you can actually “float” a small needle on the surface of water. (The needle doesn’t truly float—it is denser than water. It is held in place by the force of hydrogen bonding between water molecules lying below and around the needle.) If the water were HEATED, WHAT would LIKELY happen to the needle and WHY? Critical Thinking
(1) Capillarity (result of BOTH cohesion AND adhesion of water) Property of water to be PULLED UP a straw OR a stem of a plant.
(2) Most automobiles have water-cooled engines. What must be true about a SOLUTION that can replace water in the cooling system, such as ANTIFREEZE? Critical Thinking
(3) Cells contain mostly WATER. What might happen to the stability of an organism’s INTERNAL TEMPERATURE with respect to environmental temperature changes if cells contained mostly OIL, which does NOT have extensive hydrogen bonding? Critical Thinking
(B) Temperature Modification (Crucial to LIFE) Water MUST gain or lose a HUGE amount of THERMAL energy for its temperature to SLIGHTLY change. Advantage? A body that does not overheat easily (70% water) A stable environment for aquatic ecosystems, freshwater and marine.
(A) Amino Acids (20 different types; building blocks of proteins) All begin with a CENTRAL carbon covalently bonded to 4 other atoms. (1) A H atom at 1 st site. (2) A carboxyl group (-COOH) at 2 nd site (3) An amino group (-NH 2 ) at 3 rd site (4) A functional group (-”R”) at 4 th site (** SHAPE and FUNCTION **)
Bonds and is catalyzed by an enzyme (broken up OR pulled together). (1) Substrate (i.e., reactant)
(4) HIGH temperatures can WEAKEN bonds between different parts of a protein molecule, thus changing its SHAPE. How might this SHAPE change alter the EFFECTIVENESS of an enzyme? Critical Thinking
III. Lipids (3 CLASSES) NON-polar (do NOT dissolve in water) AND stores MORE NRG than carbs due to NUMEROUS C-H bonds (carbs LESS NRG C-O bonds)
(A) Fatty Acids (BUILDING BLOCKS of most LIPIDS) Unbranched C chain with TWO ends of DIFFERENT properties: (1) Hydrophilic (2) Hydrophobic CARBOXYL end of chain, polar, and “water-LOVING” HYDROCARBON end of chain, non-polar, and “water-FEARING”
(1) Triglyceride (e.g., saturated (animal) and unsaturated (plant) fats 3 fatty acids joined to a GLYCEROL molecule.
(5) Triglycerides in ANIMALS’ bodies are usually SOLID FATS, and those in PLANTS are usually OILS. However, many animal species living in the Arctic and Antarctic have a GREATER number of triglycerides that are OILS than do other animals. What advantage might the storage of body fat as OIL INSTEAD of SOLID FAT be to animals that inhabit freezing climates? Critical Thinking
Made of 3 PARTS: (1) Sugar deoxyribose (DNA) OR ribose (RNA) (2) Phosphate Group (PO 4 ) (3) Nitrogenous Base (A, T, C, G) (U in RNA) (1) Nucleotide (monomer for DNA and RNA, 4 types of nucleotides)
Extra Slides AND Answers for Critical Thinking Questions (1) Solutions that can replace water as a coolant in automobiles must have the ability to absorb large quantities of heat. (2) An organism’s internal temperature would likely change more abruptly and drastically in response to environmental temperature changes. (3) Heating the water would cause the water molecules to move about and the hydrogen bonds to break, thus allowing the needle to eventually fall through the surface of the water. (4) Changing the shape of an enzyme may affect its ability to function because the enzyme may no longer physically interact appropriately with its substrate. (5) Oil solidifies at a lower temperature than fat does; storing body fat as oil is helpful in freezing climates because oil is less likely to solidify in these climates than is fat.