Biology: The Dynamic Science
Peter J. Russell, Stephen L. Wolfe
Format: PDF / Kindle (mobi) / ePub
Biology: The Dynamic Science is the first general biology text with an experimental approach that connects historical research, recent advances achieved with molecular tools, and a glimpse of the future through the eyes of prominent researchers working on key unanswered questions of the day. This comprehensive framework doesn't come at the expense of essential concepts. Rather, it provides a meaningful, realistic context for learning all of the core material that students must master in their first course. Written "from the ground up" with minimal jargon and crisp, straight forward explanations of the current state of biological knowledge, the text supports students as they learn the scientific process-and how to think as scientists do.
becomes a nonﬂuid gel. In a paradoxical way, cholesterol also helps protect against the adverse eﬀects of low temperatures. Cholesterol in the membrane decreases membrane ﬂuidity at moderate to high temperatures because of Outside cell Carbohydrate groups Integral proteins Integral proteins Glycolipid Plasma membrane Cholesterol Gate Integral protein (gated channel protein) Peripheral proteins Integral protein (transport protein) Glycoprotein Cytosol Peripheral protein (linking
The net movement of solutes is into the cell. b. There is no concentration gradient. c. There is a potential for plasmolysis. d. The solvent will move against its concentration gradient. e. If this were a plant cell, turgor pressure would be maintained. Using the principle of diﬀusion, a dialysis machine removes waste solutes from a patient’s blood. Imagine blood runs through a cylinder wherein diﬀusion can occur across an artiﬁcial selectively permeable membrane to a saline solution CHAPTER 6
pathways in mammals and other vertebrates. The receptors that bind these hormones control such varied cellular responses as the uptake and oxidation of glucose, glycogen breakdown or synthesis, ion transport, the transport of amino acids into cells, and cell division. For example, a cAMP pathway is involved in the regulation of the level of glucose, the fundamental fuel of cells. When the level of blood glucose falls too low in mammals, cells in the pancreas release the peptide hormone glucagon.
phosphates to the receptor to activate it. a. 2, 1, 4, 3, 5 b. 5, 3, 4, 2, 1 c. 4, 1, 5, 2, 3 d. 4, 2, 5, 1, 3 e. 2, 5, 3, 4, 1 CHAPTER 7 C E L L C O M M U N I C AT I O N 155 5. 6. 7. 8. 9. 156 Which of the following is the ability of enzymes, requiring few receptors, to activate thousands of molecules in a stepwise pathway? a. autophosphorylation b. second-messenger enhancement c. ampliﬁcation d. ion channel regulation e. G protein turn-on Which of the following is incorrect about
chains. d. lack glycerol. e. are not stored in cells as triglycerides. Which of the following statements about steroids is false? a. They are classiﬁed as lipids because, like lipids, they are nonpolar. b. They can act as regulatory molecules in animals. c. They are composed of four interlocking rings. d. They are highly soluble in water. e. Their most abundant form is as sterols. The term secondary structure refers to a protein’s: a. sequence of amino acids. b. structure that results from local