| | | A) | cytoskeleton | | | B) | fluid mosaic model | | | C) | impermeable membrane | | | D) | genetic material | | | | | | Feedback: Phospholipids in the plasma membrane create a fluid environment in which other molecules can float, allowing selective permeability. This is known as the fluid mosaic model. | | 13 CORRECT | | What effect has eukaryotic evolution had on cells? | | | A) | more simplified structures | | | B) | greater adaptability
Diffusion Osmosis Lab (Title) Questions: 1. What size of molecules (monosaccharide vs polysaccharide) can diffuse through a semi-permeable membrane? 2. How will the concentration of sucrose within the dialysis tubing affect the rate that water diffuses through a semi-permeable membrane? 3.
Unit 13 P2 Describe how materials of different states pass into and out of cells. The cells plasma membrane is not only used for structural purposes. Its functions to allow certain substances in and out of the cell. It can allow other substances into the cell against the concentration gradient or allow other substances (for example waste) out of the cell. There are two ways that the cell can transport substances; passive transport processes and active transport processes.
The bilayer is selectively permeable which enables it to act as a barrier that keeps proteins, ions and other molecules where they are needed and prevents them from diffusing into areas where they are not (Wisegeek.com/bilayer. 2011). Small molecules can move through the layer automatically, this is diffusion from a high concentration to an area of low concentration, whereas water diffuses from highly concentrated areas to low concentrated areas. This process is known as osmosis and its purpose is to maintain equilibrium within the cell in order for it to function properly (Wisegeek.com/bilayer. 2011).
Solutes meaning: the substance that is being dissolved, while solvents meaning: substance being dissolved into, much like diffusion. Diffusion can be defined as particles that move from a higher concentration to areas of lower concentration. Diffusion is one of the key processes involved in the movement of materials into and out of cells throughout living systems. Osmosis is the diffusion of the water through a selectively permeable membrane from an area where it is more concentrated to an area where it is less concentrated. Different solutions can be categorized as hypotonic, hypertonic and isotonic as different concentrations.
| 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).
* An electrogenic pump is a transport protein that generates voltage across a membrane * Animal- sodium/potassium * Plants- proton pump Understand how a co-transporter works. Where you likely find one? Understand how large molecules and particles are transported across membranes including the role of Vesicles. What is meant by endocytosis? There are several types – what are they and how do they differ?
Since the membrane has a non-polar layer in its centre and two polar layers on either side, it is difficult for both polar and non-polar molecules to pass through both layers. The bilayer also contains proteins (almost 70%), namely integral and peripheral ones. The main function of the integral proteins is to facilitate the exchange of materials within the cell – one of which is diffusion, which is defined as the movement of substances from a region of higher concentration to a region of lower concentration. The purpose of this experiment is to find out the effect of varying temperature on the permeability of the cell membrane which is to be tested using a beetroot core immersed in water of different temperature and then, using spectrophotometry, finding the absorbance and transmittance percentage of the pigment that is left over. The red pigment present in beetroot (that was mentioned above) is Betalain, a water-soluble (thus making the pigment is suitable for diffusion into an aqueous environment) glycoside with some or all of the sugar groups removed.
Fibre and other digested foods as they pass through the body do not change very much until it reaches the large intestine, the process of excretion after the reaching of the large intestine depends on the type of Fibre is consumed. There are two types of Fibre: soluble Fibre and insoluble Fibre. Soluble Fibre is a Fibre that is quite helpful to nutrients, as it makes energy from consumed substances leave the body at a smoother and steadier pace. Preventing tiredness, hunger pains, lack of energy and strength. Soluble Fibre when passing through the large intestine absorbs the water turning the faecal matter much softer, allowing the waste to pass through the body quickly.
Strategy For this coursework, I will be investigating the following question: ‘How do different concentrations of salt solutions affect the mass of the potato after the process of osmosis?’ Osmosis is the movement of water particles from a high concentration of water particles to a low concentration across a partially permeable membrane. A partially permeable membrane is a membrane that acts as a barrier to some molecules but allows others to freely diffuse through. The partially permeable membrane of cell membranes prevent large molecules such as Sucrose, protein and starch to pass through but allow smaller molecules such as oxygen, carbon dioxide and water, glucose and amino acids to proceed. In this coursework we will be using potato to test the rate of osmosis. If the area around a cell has a higher water concentration it will gain water by osmosis.