Bio 211 Exam 1 Practice Questions and Correct Answers

The most common isotope of carbon contains a nucleus with 6 protons and 6 neutrons. Suppose you have a beaker containing 6 grams of pure carbon. Approximately how many moles of carbon are present in the beaker? Eukaryotic cells move when their flagella or cilia bend. How does the bending of these structures occur? A) The Golgi apparatus transports numerous vesicles to these structures, making them bulge. B) Actin filaments are bound by the motor protein myosin. C) The motor protein dynein changes its position on the surfaces of microtubules. D) The mitochondria within these structures rapidly change shape. C) The motor protein dynein changes its position on the surfaces of microtubules. What role does the membrane bound receptor play in signal transduction pathways? A) It binds to DNA and activates transcription. B) It binds to GTP and becomes an activated G protein. C) It amplifies the signal by making more extracellular signalling ligands. D) It interacts with the extracellular ligand and starts a signal transduction cascade on the interior of the cell. D) It interacts with the extracellular ligand and starts a signal transduction cascade on the interior of the cell. Acetylcholine is a neurotransmitter that binds to receptors on skeletal muscle cells. Binding of acetylcholine to the receptors causes contraction of skeletal muscle. One component of the venom from a black widow spiders causes release of very high levels of acetylcholine. What effect would this have on the victim of a black widow spider bite? A) The extracellular matrix between skeletal muscles would break down. B) Skeletal muscles would contract and then be unable to relax. C) Skeletal muscles would fail to contract. D) The skeletal muscles would begin to grow and divide uncontrollably. B) Skeletal muscles would contract and then be unable to relax. Which of the following osmotic situations would likely cause a red blood cell to shrink and become wrinkled? A) placing the cell into distilled water, so that the surrounding solution is hypotonic relative to the cell B) placing the cell into a solution with a high concentration of salt (eg. water from the Great Salt Lake), so that the surrounding solution is hypertonic relative to the cell C) placing the cell into seawater, so that the surrounding solution is isotonic relative to the cell B) placing the cell into a solution with a high concentration of salt (eg. water from the Great Salt Lake), so that the surrounding solution is hypertonic relative to the cell The -COO- (ionized carboxyl) group on the side chain (R-group) of aspartic acid can contribute to protein folding by A) forming ionic bonds with other negatively charged amino acids B) causing the formation of a beta sheet C) contributing to the formation of the hydrophobic core of the protein. D) forming ionic bonds with amino acids that have positively charged side chains E) interacting with the hydrophobic interior of the phospholipid bilayer. D) forming ionic bonds with amino acids that have positively charged side chains Which of the following biological molecules contains sugars (carbohydrates) as part of its structure? A) glycogen B) RNA C) DNA D) amino acids E) A, B, and C E) A, B, and C