Explain how this can lead to either a graded potential or a hyperpolarization. Depending on which ligand gated ion channel the neurotransmitter binds to will determine the kind of change that occurs on the postsynaptic membrane. Opening of channels such as sodium channels which will make the inner membrane surface more positive will depolarize the membrane. Whereas opening of channels such as potassium channels that will make the inner membrane surface less positive will hyperpolarize the membrane.
| Investigating Osmosis Through Living Membranes | Introduction: Diffusion is the tendency of molecules or ions to move from an area where they are in higher concentration to an area where they are in lower concentration, that is, down or along their concentration gradient (Marieb 2013). Osmosis is a special case of diffusion defined as the diffusion of a solvent, such as water, through a selectively permeable membrane (Marieb 2013). Osmosis occurs whenever the water concentration differs on the two sides of a membrane. Take a U-shaped container filled with a solution and separate the container into left and right compartments by a permeable membrane. Normally, net diffusion of both solute and water occurs until the concentration of water (and solute) is the same on both sides of the membrane (equilibrium).
D1; Analyse the role of the phospholipid bilayer in terms of the movement of materials into and out of cells The phospholipid bilayer is the structure which surrounds a cell, this plasma membrane is made up of two layers of phospholipids; these are the intracellular layer, which is at the bottom, and the extracellular layer which is at the top (Wisegeek.com/bilayer. 2011). The mosaic model shows that the phospholipids are arranged in shapes like heads and tails, the polar heads are made up of glycerol, phosphate and nitrogen and the non-polar tails are made up of fatty acid chains (Wisegeek.com/bilayer. 2011). The polar heads will interact with water as they are hydrophilic, though the tails/fatty acids are never exposed to water therefore they are hydrophobic (Wisegeek.com/bilayer.
The Effect of Diffusion and Osmosis on Hypertonic and Hypotonic Solutions. Introduction: In order to maintain homeostasis, a cell must be able to transport materials back and forth across the membrane due to the fact that cell membranes are selectively permeable. Selectively permeable means that some substances can pass through the membrane while others cannot, like glucose, proteins and carbohydrates. Both solutes and solvents may cross the cell membrane. Solutes meaning: the substance that is being dissolved, while solvents meaning: substance being dissolved into, much like diffusion.
A) is neutralized by water B) is surrounded by water molecules C) reacts and forms a covalent bond to water D) aggregates with other molecules or ions to form a micelle in water Answer: B Page Ref: Section 3 11 9) Which would you expect to be most soluble in water? A) I B) II C) III D) IV Answer: A Page Ref: Section 3 10) Solutes diffuse more slowly in cytoplasm than in water because of A) the higher viscosity of water. B) the higher heat of vaporization of water. C) the presence of many crowded molecules in the cytoplasm. D) the absence of charged molecules inside cells.
The membrane potential is due to the presence of an ionic concentration difference and electrical gradient between both sides of the membrane.movement of charged molecules across the cellular membrane leads to the creation of electrical signals. b. What two characteristics must a membrane possess in order to generate and maintain electrical signals critical to nervous tissue? The two traits required for electrical signal generation and maintenance is the presence of a resting membrane potentials and ionic pumps that maintain ionic concentration and electrical gradients between the two sides of the membrane. Membrane Transport Proteins 4.
They are used to speed up the reaction rates by providing an alternative reaction pathway of lower activation energy, which is the minimum energy that requires for reactions occur. Catalysts take part in a reaction (chemical involved), but they do not undergo any changes in chemical reaction. (Farabee, 2001) Enzymes are proteins made of a combination of different amino acids. Therefore, the enzymes may be lost
Also a larger concentration gradient produces a faster diffusion, and smaller molecules diffuse more rapidly than larger molecules. If you imagine a crystal of dye in a beaker of water, the crystal would be the solute because it is the dissolvable substance, and the water is the solvent because it’s what the solute dissolves into and there tends to be more of it, both of these form together to create a solution. If you look at the colour of the water just next to the crystal it would be
2. Explain why denatured sucrase was used as a control. to determine if a true effect was made on the active sucrase by ph, temperature and sucrose or if affect would be seen on both denaturated and active sucrase 3. Alkaline DNS denatures sucrase. Explain why it is important to denature the enzyme.
For example, the reaction |BaCl2•2H2O ( BaCl2 + 2H2O |(2) | is reversible, and if water is added to the anhydrous salt BaCl2, formation of BaCl2•2H2O takes place: |BaCl2 + 2H2O ( BaCl2•2H2O |(3) | The reaction of dehydration of hydrated ferrous sulfate |FeSO4•7H2O ( FeSO4 + 7H2O |(4)