BIO 208 gardner CSULB final Exam Graded A+

What is tonicity? - Answer-The ability of a solution to cause a cell to shrink or swell. Why does it matter if you are hypotonic or hypertonic? What happens during these conditions? - Answer-If the interstitial fluid has greater solute concentration than that of the cytosol, water from inside the cell flows out causing the cell to crenate and blood pressure to increase. If the interstitial fluid has less solute concentration than that of the cytosol, water flows into the cell and it undergoes hemolysis, dehydrating you. What is simple diffusion? when is it used? for which substances? - Answer-the passive movement of small molecules through the plasma membrane. (Molecules such as: O2, CO2, NO2) O2 exchange between the arteries and tissues What is facilitated diffusion? when is it used? - Answer-are the passive movement of ions or molecules through a channel. Mass movement of water through aquaporins What is active transport? when is it used? - Answer-the movement of ions against a concentration gradient. Uses energy (ATP). Na+/K+ pump. (3Na+ out/2K+ In =repolarization) What is hydrolysis? - Answer-The process of breaking substances with H2O; breaks down ATP aka burst of energy. Why do you need O2? - Answer-O2 is the final electron acceptor so therefore we need it to make ATP.How is O2 transported in the blood? - Answer-O2 is transported in the blood via hemoglobin and dissolves in plasma Why do we need to get rid of CO2? - Answer-We need to get rid of co2 to maintain pH balance. What happens to pH if we have too much CO2? - Answer-If we have too much co2, ph goes down which means it is too acidic. How is pH measured? - Answer-pH is measured by looking at the concentration of hydrogen ions If it is more concentrated, the pH is lower. Which organs help you to maintain pH Homeostasis? - Answer-The organs that help are kidneys and lungs. How is the resting potential determined? - Answer-Negatively charged organic phosphates and proteins stay in the cell, contributing to an overall negative charge. 3Na+ are pumped out and 2K+ are pumped into the cell by ATPase pumps so there is more positive charge being pumped out than pumped in, also giving a negative charge. Cell membrane is more leaky to K+ which is constantly coming out by facilitated diffusion, faster than Na+ can diffuse in so this also gives a more negative charge. What does the word interstitial mean? - Answer-It means extracellular fluid, so all the fluid outside of the cell is interstitial fluid. What does the Na+, K+ ATPase do? Why/when is it important? - Answer-3 Na+ out and 2 K+in. It is important because it keeps cell at resting membrane potential, as well as helping it revert back to resting state after an action potential. Where is the pacemaker of your heart? What does itdetermine? - Answer-SA nodes; contains pacemaker cells that are highly permeable to Na+, allowing the constant generation of action potential. It determines your resting heart rate. What is blood flow through the heart starting at the vena cava? - Answer-Superior inferior vena cava and coronary sinus > right atrium > tricuspid valve > right ventricle > pulmonary valve > pulmonary trunk > pulmonary arteries > lungs > pulmonary veins > left atrium > mitral valve > left ventricle > aortic valve > ascending aorta > aortic arch. When are the valves of the heart closed/open? - Answer-The valves are open during diastole. The valves are closed during systole and isovolumetric contraction. Why do we need valves? Where do we see valves? - Answer-We need valves to prevent backflow and and we see them in the heart, lymphatic vessels and in veins.