Study Guide for Chapter 1 - Study Guide for Chapter 1: Cell...

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Study Guide for Chapter 1: Cell Structure and FunctionLearning Objective 1.Understand the basic structure and functions of the cell membrane.1. Explain the importance of cell function from the standpoint of the Integration of CellFunction. Describe the 2 cellular communication mechanisms and the three membranetransport mechanisms.The proper function of cells is very important to everyday life. Whether replicating,transcribing, or even adapting the exterior environment, cells must be able to adapt. Thecells in a living thing are all working together and must do so to ensure the organism cansurvive growth and development. To, cells in the liver, stomach and kidney must be able toadapt to harmful foreign objects such as drugs, alcohol, foods, or infectious material within afood substance. Cell function with regards to Integration of Cell Function is an importantpart of organism existence in the cell-to-cell communication, adaptation and transportation.Cell communication is done so by two ways: cell surface receptors and intracellularreceptors. The cell chemically sends information to the receptors on the intended cell. Withcell surface receptor communication, there are three types: g-protein-linked receptors,enzyme-linked receptors, and ion channel-linked receptors. G-protein-linked receptors arenamed so, because they are linked to guanine nucleotides such as GDP or GTP. A specificligand or first messenger binds to the membrane spanning receptor; a conformationalchange takes place, activating the G protein found inside the cell, also activating theGTPase cycle. The activation causes the alpha subunit to dissociate from the receptor, betaand gamma subunit. The effector becomes activated which in turn activates the productionof cAMP, the second messenger. Eventually, the desired action, whether muscle contractionor relaxation, is reached. Enzyme-linked receptors are similar in the sense that they spanthe membrane, but do not have a cytosolic G-protein portion. Instead, the cytosolic portionis intrinsic enzyme activity or direct contact with an enzyme. Once bound to the enzyme, thesecond messenger is activated and carries out the stimulus. Lastly, ion channel-linkedreceptors are involved in the transmission of nerve and muscle impulses; the link betweenrapid synaptic signaling of electrically excitable cells. It is done by opening or closing ionchannels within the membrane. Intracellular receptors are within the cell and receivehormones that come across the cell membrane. The receptors move the hormone stimulusto the nucleus where it binds to DNA therefore increasing mRNA production and ultimatelyincreasing the protein production which alters cell activity.Membrane transport is done so by three mechanisms: diffusion, active transport, andvesicular transport. Diffusion is the movement of substances from an area of high to lowconcentration, with the concentration gradient and does not require ATP. Simple diffusion

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Term
Fall
Professor
LeeHannah
Tags
Adenosine triphosphate, Ion channel

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