BIOSC 048: Problem Set Questions 1. Given that cell A has significantly more nongated K+ channels than cell B‚ which cell has the larger resting membrane potential? Explain. If the permeability to K is higher in A than in B‚ then the resting membrane potential (rmp) will be closer to the equilibrium potential in cell A‚ which means the rmp will be more negative in cell A than in cell B; or in other words‚ the potential difference will be LARGER in cell A. 2. Predict the effect of a reduced
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3.1 BIOLOGICAL MEMBRANES 3.1.1 Properties of Cell Membranes • Separates living cell from its nonliving surroundings. • 8 nm thick. • Selectively permeable - allows some substances to cross more easily than others. 4.1.2 Fluid Mosaic Model • Singer and Nicolson (1972) - plasma membrane is a mosaic of proteins dispersed within lipid bilayer‚ with only bilayer‚ the hydrophilic regions exposed to water. Hydrophilic region of protein Phospholipid bilayer Hydrophobic region of protein
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BCR: Which Towel? A student asks a testable question: “Which brand of paper towel absorbs the greatest volume of water?” Design an investigation to provide an answer for the student. Be sure to include • the materials needed. • a numbered procedure. • the independent and dependent variables. • important data that will answer the question. • ways to help ensure the accuracy of the results. Materials: Several paper towels‚ a flat dish‚ bottled water‚ a thermometer‚ a tong
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Biological Membranes Lipid Membranes • Receptors‚ detecting the signals from outside: Light Odorant Taste Chemicals A Hormones Neurotransmitters Drugs • Channels‚ gates and pumps • Electric/chemical potential Neurophysiology Energy • Energy transduction: Photosynthesis Oxidative phosphorylation • • • • • • Structure Function Composition Physicochemical properties Self-assembly Molecular models highly selective permeability barrier Internal membranes for organelles Bilayer Permeability
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Name two properties of this polymer. e) Name two uses for this type of polymer. 4. a) What is addition polymerisation? b) Polyethylene is an example of an addition polymer. Describe what happens to the ethene molecule during this process. c) The mechanism of addition polymerisation consists of three steps. Name each step and give a brief description of each. 5. a) What is condensation polymerisation? b) Where is condensation polymerisation
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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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Diffusion is the movement of molecules (or ions) from a high concentration to low concentration. Diffusion is form of passive transport as energy 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
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Water is also known as H2O. I am made of two Hydrogens and one Oxygen. I love to travel and can be found in every home in the United States. I can change into many different shapes and can go almost anywhere if I am given the chance. My story starts in a well in my back yard at my home. I come from an underground aquifer. I can travel through the pipes into my kitchen faucet. I have many uses. I can be hot‚ warm or even cold. I can be mixed with dish soap in the kitchen sink or ran through
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stress that various alcohols have on biological membranes. Using five solutions of differing alcohol concentration for each of the three alcohols; methanol‚ ethanol‚ and 1-propanol and a small slice of beet‚ the stirred solution was placed into a plastic cuvette and then into a spectrophotometer and the absorbance of alcohol solutions were determined in order to conclude which alcohol and concentration of alcohol had the greatest effect on biological membranes. The results showed that the most non-polar
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Cell Membrane The Cell Membrane- The cell membrane is a semi-permeable membrane that surrounds the cytoplasm of a cell; the cell membrane is made up of phospholipids‚ proteins and carbohydrates. Its function is to protect the integrity of the interior of the cell allowing certain substances into the cell‚ while keeping other substances out. The phospholipids form a thin‚ flexible sheet while the proteins float in the phospholipid sheet like an ice berg‚ and the carbohydrates extend out from the
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