AP® BIOLOGY 2012 SCORING GUIDELINES Question 1 Note: At least 1 point must be earned from each of parts (a)‚ (b)‚ (c)‚ and (d) in order to earn a maximum score of 10. The ability to reproduce is a characteristic of life. (a) Describe the process of embryological development in a typical vertebrate embryo‚ beginning with a fertilized egg and ending with the development of three tissue layers. (4 points maximum) Embryological process Fertilization Cleavage (can occur in other stages)
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Diffusion is when molecules move into available space. It’s the spread of something more widely. Substances diffuse in high concentrated area to a low concentrated area. Water is one molecule that can diffuse freely in a cell. Other molecules need assistance through the cell membrane through a process called facilitated diffusion. Osmosis moves from an area of low concentration to high concentration. In osmosis water moves in the opposite way. Water flow is determined by the concentration‚ not
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Diffusion Introduction Diffusion is the net movement of ions or molecules from a region of high concentration to a region of low along the concentration gradient until equilibrium has been reached. The steeper the gradient the faster the rate of diffusion. There are a few types of diffusion. Three (3) of those are: Facilitated Diffusion- refers to diffusion of substances across a cell membrane with the help of transport protein. Dialysis- refers to the diffusion of solutes across a semipermeable
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Ronald Wilson Pd:4th 11/16/12 Introduction In this experiment diffusion and osmosis is the main idea. When using diffusion and osmosis you are trying to separate different solute concentrations on either side of the membrane. Only a solute’s relative concentration‚ or water potential‚ affects the rate of osmosis. The higher the concentration of solutes‚ the faster water will flow through the membrane to equalize the concentration. The way we describe the movement from higher to lower concentration
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Practical 1- An experiment to observe the features of an Onion Cells Method: Gather all equipment that will be used for the experiment and check that they are clean and undamaged. Using forceps‚ peel the membrane from the underside of a small piece of onion. Place the membrane flat on a clean‚ glass slide and add one drop of iodine solution. Use a pin to carefully lower the cover slip over the slide‚ ensure there are no air bubbles before the use of the slide. Set the microscope to its lowest
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Osmosis is the spontaneous net movement of solvent molecules through a partially permeable membrane into a region of higher solute concentration‚ in the direction that tends to equalize the solute concentrations on the two sides.[1][2][3] It may also be used to describe a physical process in which any solvent moves‚ without input of energy‚[4] across a semipermeable membrane (permeable to the solvent‚ but not the solute) separating two solutions of different concentrations.[5] Although osmosis does
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[pic] [pic] [pic] [pic] [pic] ----------------------- Why use Abscitrim? The active ingredient in Abscitrim is Abscisic Acid. Abscitrim is highly concentrated form that that is potent and highly effective. What it does: - induces the closure in stomata to prevent transpiration and water loss - prevents fruit ripening - promotes seed dormancy by stopping cell growth and seed germination -stops synthesis of Kinetin nucleotide -Kinetin: cytokinin
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the aim and background information 2.1. Diffusion is the spontaneous kinetic movement by which molecules move from an area of a high concentration to an area of low concentration. Diffusion continues until it reaches equilibrium. Osmosis is similar to Diffusion but it’s the process in which water moves across a semi-permeable membrane and goes to the higher concentration of solute.1 2.2. Important factors to Osmosis and Diffusion include Temperature‚ Concentration and Surface area
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Dissolved Oxygen and Aquatic Primary Productivity By: Mayank Makwana AP Biology Mrs. Biondo September 19‚ 2012 Design Diagram Dissolved Oxygen: Title: The effect of the temperature of water on the concentration of dissolved oxygen Hypothesis: If the temperature of the water is increased‚ then the concentration of dissolved oxygen will decrease. |Independent Variable: Temperature of water (Cº)
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Biology 107 Section 1 11/4/13 Diffusion & Osmosis Introduction The purpose in this experiment was to estimate the osmolarity of potato tuber and celery cells by change of weight.Pieces of potato tuber and celery would be incubated in different sucrose solutions to find out the molarity at which weight of potato and celery tissues do not change. My hypothesis was that the Table 1: Group Data for Experiment:Estimating Osmolarity by Change in Weight Table
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