BIOL 101 Guided Reading Questions GRQs Complete and submit this GRQ as a PDF before lecture and before your online Mastering Assignment L5 GRQs Cell Signaling with Hormones Reading Objectives Differentiate between chemical and electrical signaling to cells Describe how the two types of chemical signaling mechanisms affecting target cells differently Explain the consequences of endocrine disruptors Explain how testosterone and estrogen affect gender development Identify functions of enzymes and the conditions they work best Explain how enzymes are inhibited Modules 26 1 2 Chemical and electrical signals coordinate body functions Hormones affect target cells using two main signaling mechanism 1 What two type of signals does the body use to communicate To maintain homeostasis cells use chemical and electrical signals to communicate through the endocrine and nervous systems Endocrine system a group of interacting glands and tissues that produce and secrete chemicals to initiate and maintain body functions o Release hormones chemical signals In the nervous system signals are mainly electrical and travel through neurons 2 How do they affect different responses in the body Endocrine system is well suited for gradual changes that affect the whole body o Coordinate the body s responses to stimuli such as dehydration low glucose Nervous system is well suited for immediate and rapid responses to the environment stress puberty o Survival instincts Endocrine Glands where hormones are made and secreted 3 What does a target cell have that allows it to respond to a hormone secreted from a distant gland that a non target cell is lacking Endocrine Signaling membrane enclosed secretory vesicles in an endocrine cell are full of hormone molecules the endocrine cell secretes the molecules which then diffuse into the blood vessels only target cells have receptors for specific hormones Neurosecretory Cells specialized neurons that perform functions in both systems 4 List and describe the three stages of hormone signaling Reception occurs when a hormone binds to a specific receptor protein on or in the target cell each cell has a unique shape that functions to recognize a specific signal Signal Transduction convert the signal from one form to another Response change in cell s behavior 5 Are hormone receptors on the plasma membrane or inside cells BIOL 101 Guided Reading Questions GRQs Complete and submit this GRQ as a PDF before lecture and before your online Mastering Assignment 6 Draw a quick diagram outlining the differences between water soluble hormone signaling o Polypeptides proteins and some modified single amino acids o Most produced by the endocrine glands are water soluble o Cannot pass through the phospholipid bilayer Bring about change without entering the cell receptor proteins are mainly in the plasma membrane o Molecule binds to receptor protein initiating a signal transduction pathway a series of changes in cellular proteins that converts an extracellular chemical signal to a form that brings about response the final relay molecule activates a protein that carries out the cell s response which may occur in the cytoplasm or the nucleus Lipid soluble hormone signaling o Steroid hormones small molecules made from cholesterol Only sex organs and the adrenal gland produce steroid hormones o Pass through the phospholipid bilayer and bind to receptors inside the cell o A hormone enters a cell by diffusion binding to an open receptor protein in the cytoplasm or nucleus the hormone receptor carries out the signal transduction this complex attaches to sites on DNA the binding to DNA stimulates gene regulation 7 Why can steroid hormones pass through the plasma and nuclear membranes Because they are lipid soluble Modules 26 8 9 Diabetes is a common endocrine disorder The adrenal glands mobilize responses to stress 1 What organ secretes insulin and glucagon Pancreas secretes digestive enzymes into the small intestine and secretes two protein hormones insulin and glucagon into the blood Antagonistic Hormones insulin beta cells and glucagon alpha cells o Controls the amount of glucose energy source for animals in the body o Insulin lowers glucose it is taken up by all cells and excess glucose is stored in liver and muscle cells as a polysaccharide glycogen o Glucagon increases glucose glycogen stores are broken down and glucose is returned to the blood 4 Diabetes as a group of diseases affects 1 in 11 Americans What is diabetes Diabetes mellitus hormonal disorder caused by the body s inability to produce or use insulin decreasing the absorption of glucose from the blood resulting in an elevated level of blood glucose or hyperglycemia o Cells cannot obtain enough glucose from the blood even though there is plenty 5 Compare and contrast the differences in hormone signaling defects in type 1 vs type 2 diabetes Type 1 insulin dependent the body s autoimmune disorder in which the body s own immune system attacks and destroys the pancreatic beta cells that release insulin BIOL 101 Guided Reading Questions GRQs Complete and submit this GRQ as a PDF before lecture and before your online Mastering Assignment Type 2 non insulin dependent insulin is produced but the signal is not relayed normally inside the target cells the beta cells adapt by producing even more amounts of insulin 6 What condition occurs if too much insulin is produced or injected Hypoglycemia blood glucose levels drop way below normal ADDITONAL KNOWLEDGE FUN Check out this short 2 min video to about diagnosing diabetes Take notes if it helps you https www youtube com watch v bIhy Rb2xp4 Module 5 13 and 5 14 Enzymes speed up the cell s reactions by lowering energy barriers A specific enzyme catalyzes each cellular reaction 1 What does the activation energy of a chemical reaction specifically do to reactants Activation Energy activates the reactants so that energy can be absorbed and new bonds can form o Protects highly ordered molecules from spontaneously breaking down 2 What do enzymes do to the activation energy Enzymes molecules that function as catalysts increasing the rate of a reaction without being consumed by the reaction almost all are proteins o Lowers the activation energy needed for a reaction to begin 4 True or False Defend your answer for each i e explain why a particular statement is true or correct a false statement F Enzymes are consumed in reactions Substrate is another word for reactant a specific reactant that an enzyme
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