This is a summation of the concepts that I feel are most important for students to understand for the first test of the semester The test will cover material from chapters 1 5 and will focus mainly on the information that I stressed during lecture This is not meant in any way to be a comprehensive collection of knowledge required for the test Instead it is a list of general principles on which you should focus your studies If you thoroughly understand and can apply all of the concepts listed here you should do well on this test In order to perform well on this test each student should Chapter 11 Cell Communication Essentially the entire chapter with special focus on G protein coupled receptors Understand the basic reasons why cells of a multicellular organism need to communicate Cells signal each other to interpret signals they receive from other cells and the environment Understand the basic method by which cells communicate o Receptor Ligand interactions the binding between a signal molecule ligand and receptor is highly specific o Changes in receptor shape in response to ligand binding Know the three major types of membrane associated receptors o Focus on the G protein coupled receptors G protein receptors are cell surface trans membrane receptors that work with the g protein G proteins bind the energy rich GTP o What is the relationship between the receptor and the G protein G protein bind the receptor and G proteins and the GPCR G protein coupled Study Guide for Exam IV Dec 4th receptors are very similar in structure Fall 2014 o Distinguish between GDP and GTP bound G proteins and the nature of activation Know the one type of intracellular receptor o What types of signaling molecules are most likely to bind to intracellular receptors In long distance signaling plants and animals use chemicals called hormones Specialized cells release hormones which travel to target cells via the circulatory system Understand the two major signal transduction mechanisms that we discussed o Phosphorylation cascades Protein Kinases transfer phosphates from ATP to protein a process called phosphorylation Most of the relay molecules in signal transduction pathways are protein kinases creating a phosphorylation cascade o Second Messengers Small nonprotein water soluble molecules or ions that spread throughout a cell by diffusion Know the three different second messengers that we discussed and how they are activated or produced Cyclic AMP cAMP is widely used Adenylyl cyclase an enzyme in the plasma membrane converts ATP to cAMP in response to an extracellular signal Calcium ions act as secondary messengers because its concentration in the cytosol is normally much lower than the concentration outside the cell Know the three major types of cellular response to signaling and the molecules and cellular machinery involved in each Study Guide for Exam IV Dec 4th o Transcriptional o Behavioral o Enzyme Activation Regulates the activity of enzymes rather than their synthesis Reacts in the cytoplasm A signal could cause opening or closing of an ion channel in the plasma membrane or a change in cell metabolism Understand the mechanisms involved in differential cellular responses to signaling o How can a cell amplify a signal Enzyme cascades amplify the cell s response to the signal At each step the number of activated products is much greater than in the preceding step o How do two different cells respond differently to the same signal Different kinds of cells have different collections of proteins and therefore the potential to respond differently to the same signal o How can scaffolding proteins enhance the efficiency of a signal Can increase the signal transduction efficiency by grouping together different proteins involved in the same pathway Know the basics of apoptosis o What happens to a cell undergoing apoptosis Components of the cell are chopped up and packaged into vesicles that are digested by scavenger cells Apoptosis prevents enzymes from leaking out of a dying cell and damaging neighboring cells o The signal that triggers apoptosis can come from either inside or outside the cell Study Guide for Exam IV Dec 4th Fall 2014 The pathway that controls apoptosis in C elegans involves transduction steps that include negative regulation inhibition Chapter 42 Circulation and Gas Exchange 42 1 42 2 the blood pressure section of 42 3 and general blood components in 42 4 Understand the need for a circulatory system in larger multicellular organisms Every organism must exchange materials with its environment Exchanges end up occurring at the cellular level by crossing the plasma membrane o Gas and nutrient exchange is terribly slow beyond a few cell diameters Diffusion is only efficient over small distances In most animals cells exchange materials with the environment via a fluid filled circulatory system Understand the example of the gastrovascular cavity as a simple example of gas exchange Gastrovascular cavity is for animals who lack a circulatory system Functions in both digestion and distribution of substances throughout the body one opening for ingestion and elimination Study Guide for Exam IV Dec 4th Be able to describe the difference between open and closed circulatory systems In insects arthropods etc blood bathes the organs directly in an Open Circulatory system An open circulatory system has no distinction between blood and interstitial fluid This mix of the two is known as hemolymph A closed circulatory system is used by vertebrates In this type of system blood is confined to vessels and is distinct from the interstitial fluid Study Guide for Exam IV Dec 4th They are more efficient at transporting fluids to tissues and cells Pic 1 open system Pic 2 closed system Fall 2014 Be able to describe the difference between single and double closed circulatory systems Study Guide for Exam IV Dec 4th Single circulation is when blood leaves the heart and passes two capillary beds before returning basically one big loop where the blood only flows in one direction A double circulation system means that oxygen poor and oxygen rich blood are pumped separately from the right and left sides of the heart blood flows two ways in the body Study Guide for Exam IV Dec 4th Fall 2014 Know the unidirectional flow of blood through all four chambers of the human heart as well as important blood vessels of the pulmonary and systemic circuits Oxygen poor blood flows through the pulmonary circuit to pick up oxygen through
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