Exam I Review To prepare for the exam please use the following tools 1 lecture notes slides 2 the q work keys posted on Bb 3 the book 4 Me office hours or appointment Go through the membrane physiology questions after the blog questions NOW Give yourself some time These are hard but will help make sure you can work through the toughest of the material Use the slides as your guide Anything on them is fair game Think about the central question of each slide and try to anticipate questions that could be asked Homeostasis 1 Define homeostasis The process of maintaining a constant internal environment within an organism The regulation of the body s internal environment keeping it relatively stable The variables are divided into osmolarity temperature pH nutrients heart rate blood glucose levels water sodium calcium hormones and other chemicals Homeostasis DOES NOT mean equilibrium In a steady state there is no net movement of materials between compartments 2 Be familiar with the characteristics of homeostasis To maintain homeostasis the body must maintain mass balance o For example water loss by sweating and urinating must be balanced by water intake Excretion clears substances from the body o Saliva sweat breast milk and hair all contain substances that have been cleared from the body Control systems have three components an input a controller that integrates incoming information and initiates an appropriate response and an output signal that creates a response 3 4 Explain multiple mechanisms of homeostasis Compare and contrast positive and negative feedback Positive feedback o Not homeostatic o The response reinforces the stimulus rather than decreasing or removing it Exam I Review o The response sends the regulated variable cycle of ever increasing response and sends the system temporarily out of control o Requires some intervention or event outside the loop to stop the response o Examples childbirth and orgasm Negative feedback o Homeostatic designed to keep the system at or near a set point so that the regulated variable is relatively stable o Receptors feel a change in set variable control center sends commands to effectors which release hormones to change set variable back to homeostatic levels 5 Identify specific examples of positive and negative feedback Positive childbirth and orgasm Negative rising body temperature followed by sweating to lower body o temperature 6 Understand the role of feed forward control in human physiology A few reflexes have evolved that enable the body to predict that a change is about to occur and start the response loop in anticipation of the change The salivation reflex is a good example of this The sight smell or even the thought of food is enough to start our mouths watering in expectation of eating food Cell Physiology 1 Name and identify the various functions of cell organelles refer to reading from book for background Cell membrane phospholipid bilayer that is semi permeable separates the inside environment of the cell from the outside Cytoskeleton o Microvilli increase cell surface area o Microfilaments network just inside the cell membrane o Microtubules largest cytoskeleton fiber o Intermediate filaments myosin and keratin Peroxisomes contain enzymes that break down fatty acids and some foreign materials Lysosomes small spherical storage vesicles that contain powerful digestive enzymes Centrioles made from microtubules and direct DNA movement during cell division Mitochondria spherical or elliptical organelles with a double wall that creates two separate compartments within the organelle The inner matrix is surrounded by a Exam I Review membrane that folds into leaflets called cristae The intermembrane space plays an important role in ATP production Site of most ATP synthesis in the cell Golgi apparatus consists of a series of hollow curved sacs called cisternae stacked on top of one another and surrounded by vesicles Participates in protein modification and packaging ER protein synthesis calcium ions o Rough ER granular appearance due to rows of ribosomes Main site of o Smooth ER lacks ribosomes Synthesizes lipids and concentrates and stores Nucleus control center of the cell surrounded by nuclear envelope pierced by pores to allow communication with the cytoplasm Outer membrane connects to the ER Usually also contains from one to four larger dark staining bodies of DNA RNA and nucleoli 2 Characterize the structure and functions of the cell membrane including phospholipids various proteins etc Cell membrane serves like the walls of a house Some molecules can easily slip through while others cannot Proteins are important for controlling what enters and leaves the cell Responsible for physical boundary selection motility signal transduction and cellular recognition Phospholipids o Made out of a large molecule made from smaller molecules Polar non lipid group Phosphate Glycerol Fatty acid FA relatively non polar o Biochemical properties Polar charged region is attracted to other polar molecules Non polar region no net charge is attracted to other non polar molecules Where the long hydrocarbon chains of fatty acids are Amphipathic has polar and non polar domain Determinants size polarity Permeable water gases lipids Impermeable ions proteins large polar molecules 3 Understand the fluid mosaic model of the cell membrane Peripheral proteins can be removed without disrupting integrity of the membrane Phospholipid heads face the aqueous intracellular and extracellular compartments Exam I Review Lipid tails form the interior layer of the membrane Cholesterol molecules insert themselves into the lipid layer Transmembrane proteins cross the lipid bilayer 4 List the functions of membrane proteins Integral proteins tightly bound to the membrane and the only way they can be removed is by disrupting the membrane structure with detergents or other harsh methods that destroy the membrane s integrity transmembrane proteins and lipid anchored proteins Peripheral proteins attached to other membrane proteins by non covalent interactions and can be separated from the membrane by chemical methods that do not disrupt the integrity of the membrane enzymes and some structural binding proteins Transmembrane proteins classified into families based on how many segments Lipid anchored covalently bound to lipid tails that insert themselves into the they have bilayer 5 Explain the mechanism of action of various membrane transporters Alpha helices permit polar