13 THE MEMBRANES OF DIFFERENT TYPES OF CELLS ARE INVOLVED IN MANY DIFFERENT FUNCTIONS – 25 MARKS Membranes are found in all organisms‚ around and within cells. They control the movements in and out of cells‚ as well as protecting cells. They also allow different functions to occur. They have the same basic structure called the plasma membrane. All plasma membranes‚ around or inside cells have a same phospholipid bilayer structure. Phospholipids contribute to the flexibility of membranes and transfer
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Goh Biology SAC 3 “The Transport systems play an essential role in the survival of flowering plants and mammals” It is imperative that the organism’s cells have an ideal supply of the necessary materials to ensure its survival. At the same time‚ waste material must be removed to make room for the new material coming in and to avoid infection. Necessary substances and waste material merely move in and out of unicellular organisms by diffusion‚ osmosis or active transport due to direct contact with
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Lab 3 – Homework 1. Purpose of today’s experiment: To determine the effect osmotic pressure might have on cellular membranes‚ specifically when beet slices are placed in NaCl solutions of varying concentrations. 2. Hypothesis: The osmolarity will directly increase with increasing NaCl concentrations. 3. Control = Distilled Water – this was present in all solutions 4. The independent variable – salinity of the 6 solutions; while predetermined‚ the NaCl concentrations varied from 0% to 15%.
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TRANSPORT IN MAMMALS Blood is a connective tissue and every connective tissue consists of cell‚ ground substance or matrix and fibres. For blood‚ it has cells‚ matrix in the form of plasma and fibres in the form of fibrin. In transportation‚ the surface area to the volume ratio of organisms contributes to the rate of movement of materials. For example in Hydra‚ and flat worms‚ the ratio is so high so simple diffusion can allow substances to reach all tissues easily. If the ratio is low‚ in mechanisms
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Estimating Osmolarity of Plant Cells Criteria Assessed: DCP Introduction In this experiment you will be estimating the osmolarity of potato cells by finding their change in weight in solutions of known molarity. The object is to find the molarity where the mass does not change. No net change in weight indicates that there has been no net gain or loss of water. This is a means of indirectly finding the osmolarity of the cells themselves. Apparatus 1 large potato Petri dish 7 x 250 ml beakers
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plasma membrane of a cell is extremely important to the transportation of substances into and out of the cell. The outer membrane of a cell is made up of lipids and proteins. Most of the lipids in plasma membranes are phospholipids. The phospholipids have a hydrophilic head and two hydrophobic tails. When engulfed in water‚ they arrange themselves such that all the hydrophobic tails clump together‚ surrounded by the hydrophilic heads‚ protecting the tails from the exposure to the water. In cells‚ which
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The Effects of Environmental Stimuli on Animal Behavior AP Biology Emily Olsen April 26‚ 2012 I. Introduction: The purpose of this lab is to test the effect certain stimuli has on the behavior of a terrestrial isopod. These bugs are more commonly known as pill bugs and potato bugs. The objective of this experiment is to determine which kinds of habitats potato bugs favor. Potato bugs have an innate behavior called taxis which will cause the animal to move away from a stimulus that is unwanted
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the kinds of homeostasis involved. In males and females‚ intracellular fluid has a greater proportion of total body water than does extracellular fluid. Give-and-take between the ICF and the ECF happens across plasma membranes by osmosis‚ diffusion‚ and carrier-mediated transport. The kinds of homeostasis involved are fluid Balance‚ electrolyte Balance‚ and Acid–Base Balance. Fluid balance is when the quantity of water we gain each day is equivalent to the amount we lose to the environment.
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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 is an organic chemical that functions in the
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Observing Onion Cells Science 8 Observing Onion Cells ***Do not write anywhere on this piece of paper!!! It will be used again this afternoon!!!***** Instructions. On a piece of paper‚ write the title (see above)‚ the date‚ your block‚ and your name. Then copy out the problem (see below). Problem. What structures can you observe in an onion cell when using a compound light microscope? Hypothesis. On your lab report‚ below your Problem‚ write a Hypothesis that will
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