PHYS 261 Mid Term Exam 2023 Complete

PHYS 261 Mid Term Exam 2023 Complete. chemical structure of the R group. E) number of peptide bonds in the molecule. 9) Nucleic acids are polymers of units called A) nucleotides. B) fatty acids. C) bases. D) ribose. E) amino acids. 10) A component of an important buffer in the human body is A) H2O. B) NaCl. C) HCO3 -. D) HCl. E) H+. 11) The basic structural and functional unit of the human body is A) tissue. B) the cell. C) protein. D) the organ system. E) the organ. 12) Cell membranes are said to be A) actively permeable. B) impermeable. C) freely permeable. D) selectively permeable. E) none of the above 13) Most of the ATP required to power cellular operations is produced in the A) endoplasmic reticulum. B) Golgi apparatus. C) mitochondria. D) ribosomes. E) nucleus. 14) Glands that secrete hormones directly into the blood are A) endocrine glands. B) mixed glands. C) unicellular glands. D) exocrine glands. E) none of the above 15) According to the second law of thermodynamics, A) the total amount of energy in the universe never changes. B) the amount of entropy increases during natural processes. C) energy can be converted, but not be created nor destroyed. D) entropy decreases in living systems as a result of cellular processes. 16) When a chemical reaction is in equilibrium A) there are equivalent amounts of reactants and products. B) the reaction has stopped. C) there is no net change in the amount of reactants or products. D) the reaction is proceeding at its maximum rate. 17) A competitive inhibitor binds to A) the surrounding tissue. B) the product. C) the active site. D) the substrate. E) a region of the enzyme other than the active site. 18) Compartmentation refers to A) dividing metabolic reactions into groups for better understanding. B) pairing together isozymes that perform similar reactions. C) separating substrates into chemical classes. D) grouping related enzymes into specific organelles. 19) Which body fluid compartment contains higher levels of Na +, Cl-, and HCO3 -? A) plasma B) interstitial fluid C) intracellular fluid D) A and C E) A and B 20) Water is a polar molecule, yet it easily moves through the nonpolar portions of cell membranes. Which transport process is responsible? A) symport B) facilitated diffusion C) antiport D) uniport E) simple diffusion 21) An allosteric modulator binds to A) the product. B) a region of the enzyme other than the active site. C) the active site. D) the substrate. E) the surrounding tissue. 22) Saturation occurs when A) a carrier molecule has the ability to transport only one molecule or a group of closely related molecules. B) a group of carrier proteins is operating at its maximum rate. C) the energy required to move molecules results from a high-energy bond. D) a preference of a carrier protein for a substance is demonstrated based on the differing affinities of the carrier for the substrates. E) molecules are moved by the use of vesicles. 23) The resting membrane potential in a typical nerve cell is approximately A) +70 mV. B) - 70 mV. C) 0 mV. D) +70 mV. E) -7 mV. 24) As the charge on the membrane of a typical neuron approaches 0 from -70 mV, the cell is A) repolarizing. B) depolarizing. C) becoming more difficult to stimulate. D) hyperpolarizing. 25) When adenylyl cyclase is activated, A) calcium ions are released from intracellular stores. B) steroids are produced. C) cAMP is formed. D) cAMP is broken down. E) protein kinases are metabolized. 26) Negative feedback A) can prevent the initial disturbance of homeostasis. B) reinforces the stimulus. C) stabilizes the variable being regulated. D) none of the above 27) The increasingly forceful uterine contractions that lead to childbirth are an example of A) negative feedback. B) effector shutdown. C) positive feedback. D) receptor activation. E) none of the above 28) The link between a first messenger and a second messenger in a cell that responds to peptide hormones is usually A) a G protein. B) cGMP. C) cAMP. D) calcium. E) adenylyl cyclase. 29) When steroid hormones bind to their receptors, A) cyclic nucleotides are formed. B) gene transcription may start or stop. C) G proteins are inhibited. D) adenylyl cyclase is activated. E) protein kinases are activated.