This guide is meant to help you focus your studies as you prepare for our first exam. It is not meant to be exhaustive – there will likely be questions on the exam that are not explicitly covered here. But if you are comfortable with this material, you should do well on the exam. When looking for information to refresh your memory, I recommend that you start by looking at the lecture slides or recordings. Then, if you need more clarity, you can supplement that information with material from the textbook.

Introduction

• Define homeostasis, and explain what happens when homeostasis cannot be maintained.
• Understand the difference between extracellular fluid and intracellular fluid. How do they relate to compartmentation?
• Explain the difference between equilibrium and steady state; if homeostasis does not mean equilibrium, then what does it mean?
• Distinguish between a positive and negative feedback loop. What is the purpose of a feedback loop? Which type of feedback loop is homeostatic?
• Know the seven steps of a reflex response loop.

Chemical Reactions and Bonds

• List the four major groups of biomolecules and briefly describe their structures and functions.
• List and describe the four important roles electrons play in physiology.
• What are the properties of a polar molecule? Give at least one example. What are the properties of a nonpolar molecule? Give at least one example.
• Using NaCl as an example, draw how an ionic bond is formed.
• Cations have a ____ charge; anions have a ____ charge.
• Contrast hydrophilic interactions and hydrophobic interactions.
• Describe the induced-fit model of protein-ligand binding and use it to explain how proteins exhibit specificity in their ligand binding.
• What are agonists?
• Describe how temperature and pH affect protein structure and function.
• Define and distinguish between the processes of up-regulation and down-regulation.

Compartmentation

• Identify the three major body cavities and the three functional fluid compartments in the body.
• List and briefly describe the general functions of the cell membrane. Diagram the fluid mosaic model of the cell membrane. Show the orientation of the phosphate heads and the lipid tails, and include membrane proteins.
• List the three main types of lipids found in cell membranes and describe their functional roles. 
• Describe and distinguish between integral proteins, peripheral proteins, transmembrane proteins, and lipid-anchored proteins. 
• List the four primary tissue types in the human body. 
• What class of molecules is responsible for cell-cell adhesion? 
• What are the structural classifications for epithelia? What are the functional classifications for epithelia? 
• Distinguish between and give examples of exocrine glands and endocrine glands. 
• What is the distinguishing characteristic of connective tissue? 
• What is ground substance? 

Energy and Metabolism

• Define energy and list three kinds of work in biological systems and give an example of each. 
• What is a concentration gradient? 
• Describe the difference between kinetic energy and potential energy. Give an example of each. How is potential energy stored in biological systems? 
• What is entropy? 
• Compare and contrast endergonic reactions and exergonic reactions. Describe the free energy of the products in each reaction type. 
• Define enzymes and substrates. What are coenzymes? What are vitamins? 
• How does an enzyme lower the activation energy of a reaction? 
• What is the term for the process of adding a phosphate group to a molecule? What type of enzyme carries out this function? 
• Define metabolism. Distinguish between catabolic and anabolic reactions. 
• What is feedback inhibition? What role does it play in modulation of enzymes? 
• What is the advantage of having a reaction that is regulated by two enzymes (one for the forward direction and one for the reverse direction)? 
• Describe the structure of ATP. What roles does ATP play in the body? 
• Compare aerobic and anaerobic pathways. Which one produces more ATP? 
• For each of the following pathways: What key substrate(s) enter(s) each pathway? What key product(s) come(s) out of each pathway? What are the fates of these key products? Which pathways require oxygen?
  • Glycolysis
  • The citric acid cycle
  • The electron transport system (ETS)
• What makes proteins highly variable and highly specific? 

Membrane Transport

• What is chemical disequilibrium? Give some examples of specific solutes that exist in a state of chemical disequilibrium in our body.
• How does chemical disequilibrium in the body give rise to electrical disequilibrium? What is the result of electrical disequilibrium? 
• Define and describe osmosis. What is osmotic pressure? 
• Distinguish between the terms isosmotic, hyposmotic, and hyperosmotic. Contrast osmolarity and tonicity. Distinguish between the terms isotonic, hypotonic, and hypertonic. 
• What properties of a cell membrane contribute to its permeability? Give examples of substances that typically are permeable and impermeable to human cell membranes. 
• What two properties of a molecule determine whether it can diffuse across a membrane? 
• What is the difference between active transport and passive transport? 
• Define diffusion. Differentiate between protein-mediated transport, facilitated diffusion, and active transport. 
• What is the role of membrane receptor proteins?
• Diagram the general mechanism by which carrier proteins move molecules across a membrane. 
• What is active transport? Why does it require the input of energy? Diagram the structure and mechanism of the Na⁺-K⁺-ATPase as an example of primary active transport. 
• Explain what is meant by an electrochemical gradient.
• Explain the term resting membrane potential difference.
• What two factors influence a cell’s membrane potential? 
• Which four ions contribute the most to changes in membrane potential? In which fluid compartment is each ion most concentrated? 

Cell Communication

• List and describe the basic methods of cell-to-cell communication. 
• Distinguish between paracrine and autocrine signals. 
• How do chemical signals secreted by cells spread to adjacent cells? 
• What are hormones? How do they reach their targets? 
• Why don’t all cells react to hormones circulating in the body? 
• Distinguish between a neurotransmitter, neuromodulator, and neurohormone. 
• What features do all signal pathways share in common? 
• Where can receptor proteins be found in target cells? 
• Sketch a G protein-coupled receptor (GPCR) and describe how GPCRs accomplish signal transduction. Name the two most common amplifier enzymes for GPCRs. 
• Sketch an example of a receptor-enzyme and describe how receptor-enzymes accomplish signal transduction. Name two examples of enzymes found in receptor-enzymes. 
• Describe the structure and function of integrins. 
• Diagram the ways Ca²⁺ can bring about an intracellular response. How does extracellular calcium enter the cell? Where and how is intracellular calcium stored? What effects can a calcium spark initiate?
• Distinguish between an agonist and an antagonist.
• List Walter B. Cannon’s four postulates. 
• Give two different meanings for the word receptor. 

Endocrine System

• Define hormone and describe what, in general, a hormone does. List three basic ways hormones act on their target cells.
• What types of cells and tissues secrete hormones? 
• Why is it necessary for hormone action to be terminated? How is hormone action terminated?
• List three chemical classes of hormones. 
• Outline the synthesis, storage, and release of peptide hormones. Which organelle(s) is (are) involved? Explain processing from a preprohormone to a prohormone to a hormone.  
• List the tissues/organs from which steroid hormones are secreted. 
• Can steroid hormones be stored? Explain. How does this affect steroid hormone synthesis? 
• Explain nongenomic responses to steroid hormones. How do these types of responses differ from traditional steroid responses? 
• Amine hormones are derived from one of two amino acids. Name these two amino acids. 
• Describe the components of a simple endocrine reflex. What serves as the sensor? What serves as the integrating center? 
• What two neurohormones are stored and released by the posterior pituitary? Identify their functions. 
• Define the role of a tropic hormone.  What about a trophic hormone? 
• Know the six hormones synthesized by endocrine cells of the anterior pituitary and indicate their target tissue(s), and know which are tropic and which are non-tropic.
• Distinguish between long-loop negative feedback and short-loop negative feedback. Give examples of each. 
• Identify three types of hormone interactions, and give an example of each.
• What are the causes and cardinal signs of diabetes mellitus?