NU 545 Unit 1Test Bank Questions & Answers 100% Success (A+ Score)

NU 545 Unit 1Test Bank Questions & Answers 100% Success (A+ Score) What is metabolic absorption? - ANSWER-The uptake and use of nutrients and other substances from the cells surrounds (pg. 3). What uses oxygen to remove hydrogen atoms in an oxidative reaction? - ANSWER-Peroxisomes contain enzymes to use o2 to remove H atoms. This produces hydrogen peroxide. (pg 8) During cell injury what is released that is capable of cellular autodigestion? - ANSWER-Lysosomes aid in cellular digestion, seen as "trash cans and recycling agents" "as cells complete their life span and die, lysosomes digest...the debris... Lysosomes involved in this process of autodigestion are called autolysosomes or autophragms (pg 7-8). Where is the genetic info contained in the cell? - ANSWER-The nucleus contains the Nucleolus, a small dense structure composed of RNA, DNA, DNA protein. Pg 3. Cell membranes contain which major chemical components? - ANSWER-"The main components of cell membranes are lipids and proteins. The basic structure of cell membranes is the lipid bilayer..." pg 12 What allows potassium to diffuse in and out of cells? - ANSWER-Diffusion is the movement of a solute molecule from and area of greater solute concentration to an area of lesser solute concentration. (pg. 29). Active transport of K+ and Na+ requires a Sodium-Potassium Pump (pg. 31). How is the cell protected from injury? - ANSWER-Plasma membrane pg 12 table 1.1 (functions of membrane). In cirrhosis, what does cholesterol have to do with the erythrocytes? - ANSWER-causes a decrease in membrane fluidity and affects the cells' ability to transport oxygen What is platelet-derived growth factor? - ANSWER-PDGF stimulates proliferation of connective tissue cells and neuroglial cells. Can help with creating blood clots. Pg 38. What is cell communication? How does it occur? - ANSWER-Cells need to communicate w/ each other to maintain a stable internal environment, or homeostasis; to regulate growth and division... it is done by 3 main ways. 1) they display plasma membrane-bound signaling molecules (receptors) that affect the cell itself and other cells in direct physical contact. 2) they affect receptor proteins inside the target cell and the signal molecule has to enter the cell to bind w/ them. 3) they form protein channels that directly coordinate the activities of the adjacent cells. Pg 19. What is chemical signaling? - ANSWER-Primary means of cell-to-cell communication. 5 forms of signaling mediated by secreted molecules: (1) Contact-dependent signaling requires cells to be in close membrane-membrane contact; (2) Paracrine signaling- cells secrete local chemical mediators that are quickly absorbed, destroyed, or immobilized; (3) Autocrine signaling- cells produce signals that they, themselves, respond to (cancer cells); (4) Hormonal signaling involves specialized endocrine cells that secrete chemicals called hormones (TSH). Hormones are released by one set of cells and travel through the tissue and through the bloodstream to produce a response in other sets of cells; (5) Neurohormonal signaling- hormones are released into the blood by neurosecretory neurons. (p.19) How is glucose transported from the blood to the cell? - ANSWER-Pancreatic cells secrete and release insulin to signal muscle cells to absorb sugar from the blood for energy. (p.3) Understand the transportation of potassium and sodium across plasma membranes - ANSWER-The Na+ -K+ antiport system (Na+ moving out of the cell and K+ moving into the cell) uses the direct energy of ATP to move these cations. The transporter protein is the enzyme adenosine triphosphatase (ATPase). Approximately 60% to 70% of the ATP synthesized by cells is used to maintain the Na+-K+ transport system. 1, three Na+ ions bind to sodium- binding sites on the carrier's interface. 2, at the same time, an energy- containing adenosine triphosphate molecule produced by the cell's mitochondria bind to the carrier. The ATP disassociates, transferring its stored energy to the carrier. 3 and 4, the carrier then changes shape, releases the three Na+ ions to the outside of the cell, and attracts two potassium ions to its potassium- binding site. 5, the carrier then returns to its original shape, releasing the two K+ ions and the remnant of the ATP molecule to the inside of the cell. The carrier is now ready for another pumping cycle (p.31) What is active transport? - ANSWER-requires life, biologic activity, and the cell's expenditure of metabolic energy. Unlike passive transport, active transport occurs across only living membranes that have to drive the flow "uphill" by coupling it to an energy source (p. 28) What are cytokines? - ANSWER-Growth factor, also called cytokines, stimulate an increase in cell mass or cell growth by promoting the synthesis of proteins and other macromolecules and inhibiting their degradation (p. 38) Cytokines constitute a large family of small-molecular-weight soluble intracellular-signaling molecules that are secreted, bind to a specific cell membrane receptors, and regulate innate or adaptive immunity; either proinflammatory or anti-inflammatory. Majority of important cytokines are classified as interleukins or interferons (p. 201) Do all cells continue to replicate and divide? - ANSWER-No. For example, most of the neurons and skeletal muscle cells are in a terminally differentiated G0 state; with their cell cycle control system disassembled, the molecular regulatory switches become permanently turned off and cell division rarely occurs (p. 37) continues...