The Cell membrane surrounds all living cells and is the most important organelle‚ there is also a similar plasma membrane that surrounds all the organelles except for the ribosome. The membrane controls how and what substances can move in and out of the cell/organelle The structure of the membrane is often referred to as the “Fluid Mosaic Model”; this is because of the way it is structured It is composed of phospholipids‚ proteins‚ and carbohydrates‚ which are arranged in a fluid
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mosaic model of the cell membrane. What is the fluid mosaic model? The fluid mosaic model is a model conceived by S.J. Singer and Garth Nicolson in 1972 to describe the structural features of biological membranes. The membrane is described to be fluid because of its hydrophobic integral components such as lipids and membrane proteins that move laterally or sideways throughout the membrane. That means the membrane is not solid‚ but more like a ’fluid’. The membrane is depicted as mosaic because
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The plasma or cell membrane exhibits ability for the cell to discriminate in its chemical exchanges with its environment and this makes cell membrane fundamental to life. This property can only be possible because of the cell membrane’s selective permeability (Campbell and Reece‚ 2002). The structure of the membrane can be best illustrated by the fluid mosaic model where the membrane is said to be a fluid structure with various proteins embedded in or attached to a bilayer of phospholipids (Campbell
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Experiment 2 : Transport Across Membrane Name : Matrix No : Group : B Semester : 1 Date of Experiment : 05.09.2013 Lecturer’s Name : Miss OBJECTIVE To study the effects of hypotonic‚ hypertonic and isotonic solutions on plant and animal cells. INTRODUCTION In cellular biology the term membrane transport refers to the collection of mechanisms that regulate the passage of solutes such as ions and small molecules through biological membranes‚ which are lipid bilayers that
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liquid permeability of porous media. The apparatus used in the experiment is the liquid permeameter. The liquid used in this experiment is water. Three membrane samples of different thickness (0.1‚ 0.2‚ 0.3 cm) are used as the porous media. The determination of the permeability is carried out using elevated pressure test. Each sample is tested for 5 times at different values of pressure gradient which are 5‚ 10‚ 15‚ 20 and 30 psi. In order to obtain more accurate data‚ ensure that the membrane samples
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PLASMA MEMBRANE SELECTIVE PERMEABILITY= allowing some substance to cross it more easily than others composed of: Phospholipids Proteins Carbohydrates Cholesterol FLUID MOSAIC MODEL Phospholipids are primary lipids(constantly moving‚ fluidly) AMPHIPATHIC-containing hydrophobic and hydrophilic regions Mosaic part=not made of one thing Freeze-fracture studies:way to view what’s inside FLUIDITY OF MEMBRANE Move within bilayer Most of lipids and some proteins‚ drift laterally
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Sep 27 2009 15:44:17 GMT-0600 (Mountain Daylight Time) --------------------------------------------------------------------------Question 1 Differential permeability can also be described as: Correct: the allowance of only certain substances to pass through a membrane without hindrance. Compare the molecule size and the MWCO for the membrane. --------------------------------------------------------------------------Question 2 Passive transport includes which of the following processes? Correct:
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REVIEW SHEET EXERCISE 1 Cell Transport Mechanisms and Permeability NAME: LAB TIME/DATE: 1. Match each of the definitions in Column A with the appropriate term in Column B. Column A Column B __E__ term used to describe a solution that has a lower concentration of solutes compared to another solution _G___ term used to describe a solution that has a higher concentration of solutes compared to another solution _A___ the movement of molecules from an area of higher concentration to an area of
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does not need to be generated. Diffusion is complete when the concentration of molecules is equal on either side of the membrane. Diffusion rate can be influenced by many factors such as: Concentration gradient across the the membrane. Permeability of the membrane to the diffusing substance. Temperature. Surface area of the membrane. Question 2 2.1 Acetylcholine is an organic chemical that functions in the brain and body as a neurotransmitter it is an ester of acetic acid and choline. Acetylcholine
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1 The Effect of Molecular Weight on the Rate of Diffusion of Substances1 Alexander Ken Libranza Group 1 Sec. A – 1L March 6‚ 2012 A scientific paper submitted in partial fulfillment of the requirements in General Biology I laboratory under Prof. Cheryl M. Talde‚ 2nd sem.‚ 2011-2012. 1 2 ABSTRACT The effect of molecular weight on the rate of diffusion was assessed using two tests: the glass tube test and the agar-water gel test. In the glass tube set-up‚ two cotton plugs soaked
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