Bio 210 test 2 Questions with Correct Answers

Bio 210 test 2 Questions with Correct Answers Receptors for lipophobic messengers are typically located where in the cell? - AnswerPlasma membrane Which of the following are proteins on a target cell that specifically recognize and bind only one messenger or a class of messengers? - Answer-Receptors Chemical messengers derived from cholesterol fall under which category? - AnswerSteroid messengers Which of the following chemical messengers is characteristically released from an endocrine gland? - Answer-Hormone Hormones can be transported in blood in dissolved form or bound to - Answer-Carrier proteins What type of hormones bind to receptors located on the cell membrane? - AnswerWater soluble hormones, such as insulin and epinephrine Which intracellular substance degrades cAMP, thus inactivating the response to a hormone? - Answer-Phosphodiesterase Growth factor hormones, such as insulin, bind to which type of receptors? - AnswerTyrosine Kinase Receptors Which is the correct order of events for hormones activating Gs Proteins? - AnswerActivation of G protein, binding of GTP, activation of adenylate cyclose, conversion of ATP to cAMP Which second messenger causes the release of calcium from the endoplasmic reticulum - Answer-IP3 Which of the following adrenergic receptors increase cAMP levels? - Answer-B(beta) receptors Where in the cell are receptors for cholesterol derived chemical messengers typically located? - Answer-Nucleus/Cytosol The strength of binding between a messenger and its receptors is known as - Answeraffinity One of the striking features of second messengers is the ability to elicit a marked response on a target cell by small changes in the concentration of a chemical messenger. This phenomenon is known as - Answer-single amplification A chemical messenger that is released into the blood stream to travel to its target would be categorized as a(n) - Answer-hormone Chemical messengers that bind to a receptor, preventing a biological response are - Answer-antagonists Direct communication between adjacent cells is provided by - Answer-Gap junctions A change in electrical properties of the cell is most likely the result of a chemical messenger binding to which type of receptor? - Answer-An ion channel Mechanisms of intercellular communication - Answer-Direct: Gap junctions Indirect: Chemical messengers Gap Junctions - Answer-Composed of membrane proteins, link the cytosol of two adjacent cells, particle movement between cells acts as a signal, communication is direct, common in smooth and cardiac muscles. Where are gap junctions common? - Answer-Smooth and cardian muscles Chemical messengers - Answer-Messenger is produced by the source cell and released often by secretion. The messenger travels to the target cell. The target cell has receptors for the messenger. Binding of the messenger to the receptor triggers a target cell response. Communication is indirect. Paracrine Chemical messenger - Answer-Chemical that signals a nearby cell. Example is histamine which is responsible for inflammation response. Autocrine - Answer-A subclass of paracrine. Chemical signals the same cell that secreted it (talks to itself). Source and target are the same. Neurotransmitter - Answer-Messenger produced by neurons. Is released into the ECF of the synaptic cleft. Ex: ACH, GABA, serotonin. Hormone - Answer-Messenger is produced by endocrine cells. Secreted into the blood via interstitial fluid. EX: insulin, estrogen, thyroxin. Neurohormone - Answer-A special class of hormone. Messenger is produced by neurons. Secreted into the blood. Ex: ADH, oxytocin Lipophobic ligand - Answer-Water soluble. Does not cross the cell membrane, receptors are on the cell membrane. General action of target response, enzyme activation and membrane permeability changes. Lipophillic ligand - Answer-Lipid soluble. Easily crosses cell membrane, has intracellular receptors. General action of target response is via gene activation. Amino acid - Answer-Lipophobic. Target cell receptors are on the cell membrane. Only four amino acids function as messengers, all as neurotransmitters. Ex: glutamate, asparate, glycine, GABA. Amino acids are synthesized within a neuron, stored in vesicles until needed, and released by exocytosis. Amines - Answer-Most are lipophobic, except thyroid hormones. Target receptors on the cell membrane. Made or derived from an amino acid. Contains an amine group. Amines are produced in the cytosol of the source cell, stored in vesicles of the source, released by exocytosis. The amine produced is determined by which enzymes are present in the source cell.