ANSWER THE FOLLOWING QUESTIONS TO THE STUDY GUIDE Concepts to know: 1. )Be able
ID: 186101 • Letter: A
Question
ANSWER THE FOLLOWING QUESTIONS TO THE STUDY GUIDE
Concepts to know:
1. )Be able to recognize the different types of membrane molecules.
2.)Be able to give the factors that influence membrane fluidity.
3.)Know the different functions of the cell membrane.
4.)Know the basic structure of cell membranes.
5.)Be able to describe the different ways that membrane proteins associate with the lipid bilayer
6.)Know the different functional classes of membrane proteins and be able to give an example of each.
7.)Be able to give the secondary structures used by proteins to span the membrane.
8.)Be able to explain the three types of transmembrane pumps.
9.)Be able to explain Uniport, Symport and Antiport transporters and be able to give an example of each.
10.)Know the different types of gated ion channels and how they work, and be able to give an example for each.
11.)Understand what resting membrane potential is, how Sodium and Potassium ions are utilized in its establishment, and how voltage-gated ion channels are used to start and propagate an action potential.
12.)Tell how voltage-gated Ca2+ channels are important in neurotransmitter release from nerve terminals.
13.)Tell how neurotransmitters can be excitatory or inhibitory.
14.)Know the organelles of the cell and their function.
15.)Be able to explain why ER signal sequences are thought to be necessary and sufficient
16.)Know how the cell regulates the activity of transporters, receptors, and enzymatic proteins.
17.)Be able to explain, in moderate detail, the three main mechanisms of protein transport into organelles.
18.)Be able to explain how the rough ER can tell the difference between a trans-membrane protein and a water-soluble protein.
19.)Be able to describe the transport of proteins into the mitochondria and chloroplasts
20.)Be able to describe the transport of soluble, single-pass and double-pass transmembrane proteins across the ER membrane.
21.)Know what happens to improperly folded and incompletely modified proteins.
22.)Be able to explain the difference between the constitutive and the regulated secretory pathways of the cell.
23.)Be able to name the three fates of proteins after endocytosis.
24.)Be able to explain the different types of endocytosis.
25.)Be able to explain how the different types of ion channels are used by neurons to receive and transmit information.
26.)Be able to explain the formation of clathrin-coated vesicles
Explanation / Answer
1) Our cell membrane is made up of phospholipid bilayer. And in addition to phospholipid, other molecules like, cholesterol can be seen between the lipid molecules, proteins like integral membrane proteins and peripheral membrane proteins will be also present. Integral membrane proteins will be present within the bilayer whereas peripheral membrane proteins will be present on the periphery or outside the lipid bilayer. In addition, carbohydrate chains are also attached to lipid bilayer. They are attached on to the outer side of the phospholipid bilayer of the membrane and is generally called as ' Glycocalyx'.
2) The fluidity of plasma membrane can be due to a number of reasons. The well packed arrangement of lipid molecules in trans configuration is the major factor that contributes to fluidity. In addition, presence of cholesterol molecules also has a role. In fact, the presence of cholesterol molecule provide stiffness to the membrane. If the amount of cholesterol is less the membrane can become over fluid.
3) The different functions of cell membrane inclue,
a) The cell membrane always act as a physical barrier by seperating cells interior from the extracellular fluid
b) It helps to exchange materials with the cells sorroundings as they contain receptors and protein channels within them (selective permeability).
c)They posses role in cell adhesion and cell signalling
4) The cell membrane is a phospholipid bilayer that is made by the packing of lipid molecules. Lipid molecules has a hydrophobic tail region and a hydrophilic head region. So they will be arranged in such a way that the the hydrophilic head region faces the aqeous environment and the hydrophobic tail region points to the interior( thus keeps them away from water).
Within the hdrophobic tail of the lipid molecules, cholesterol molecules can be found. They are also hydrophobic and they are essential to provide stiffness to the membrane, because if cholesterol molecules are absent, then the lipid bilayer will be too loose.ie, cholesterol molecules keeps the membrane fluid at the same time flexible.
In addition both peripheral and integral memrane proteins are also present. Peripheral proteins are present within the surface of the lipid bilayer while integral membrane proteins are located within the lipid bilayer.
Carbohydrate molecules are also found attached to the outside of lipid membrane which is called as glycocalyx.
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