File Name: exercise 5 the cell transport mechanisms and permeability answer.zip
- Lights, Camera, Acting Transport! Using role-play to teach membrane transport
- 3.1 The Cell Membrane
- Transport across a cell membrane questions
Lights, Camera, Acting Transport! Using role-play to teach membrane transport
Lights, Camera, Acting Transport! The activity involves three acts in which students, representing various molecules, ions and components of the plasma membrane, interact to learn the fundamentals of passive transport, primary active transport and co-transport across cellular membranes. This activity was designed in response to observations that many students struggle to understand the basic principles of membrane transport. After consistently observing high levels of student engagement and enjoyment from this activity, we assessed student learning gains from, and attitudes towards, this exercise. Student understanding of membrane transport significantly improved after participation in the activity, and these improvements were largely retained over time.
One of the great wonders of the cell membrane is its ability to regulate the concentration of substances inside the cell. The phospholipids are tightly packed together, and the membrane has a hydrophobic interior. This structure causes the membrane to be selectively permeable. In the case of the cell membrane, only relatively small, nonpolar materials can move through the lipid bilayer remember, the lipid tails of the membrane are nonpolar. Some examples of these are other lipids, oxygen and carbon dioxide gases, and alcohol. However, water-soluble materials—like glucose, amino acids, and electrolytes—need some assistance to cross the membrane because they are repelled by the hydrophobic tails of the phospholipid bilayer. All substances that move through the membrane do so by one of two general methods, which are categorized based on whether or not energy is required.
3.1 The Cell Membrane
Summarize the results of Activity 3, diffusion through nonliving membranes, below. List and explain your observations rel- ative to tests used to identify diffusing substances, and changes in sac weight observed. Water moved into the sac by osmosis; sac gained weight. There was no net diffusion of glucose or osmosis because the water concentration on both sides of the membrane was the same. Net movement occurs only when there is a concentration gradient. NaCl diffused from the sac into the water; silver nitrate added to the water showed the presence of Cl—.
The chemistry of living things occurs in aqueous solutions, and balancing the concentrations of those solutions is an ongoing problem. In living systems, diffusion of substances into and out of cells is mediated by the plasma membrane. The passive forms of transport, diffusion and osmosis, move nonpolar materials of small molecular weight across membranes. Substances diffuse from areas of high concentration to areas of lower concentration, and this process continues until the substance is evenly distributed in a system. In solutions containing more than one substance, each type of molecule diffuses according to its own concentration gradient, independent of the diffusion of other substances. Some materials diffuse readily through the membrane, but others are hindered, and their passage is made possible by specialized proteins, such as channels and transporters. One of the great wonders of the cell membrane is its ability to regulate the concentration of substances inside the cell.
Whether a particle is allowed through depends on its size, charge, polarity and hydrophobicity:. The movement of water across cell membranes can affect cell volume, shape and cell survival. In Ex , you will observe what happens to rat red blood cells when they are placed in hypertonic, isotonic or hypotonic solutions - you should be able to think of a hypothesis to predict what will happen to the red blood cells in each of these solutions. In Ex , you will observe how the rate at which water moves across the dialysis membrane is affected by the concentration of solutes on either side of the membrane. Set up experiment 2 first and get it going - it takes the longest and is the most complicated. Divide labor among the members of your lab group - at least 2 people should be working on experiment 2. Experiment 3 can be set up and done last - it only takes about 15 minutes.
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Transport across a cell membrane questions
Diffusion is the movement of particles from high concentration to low concentration in a substance. This process is essential for life on Earth, allowing for the movement of molecular compounds into and out of the cell. All matter in the universe is in motion, because all molecules are vibrating. This constant vibration is known as Brownian motion, which can be seen as random zig - zag motion in particles.
Cell membrane of the cell 2. What is active transport? It can be Clear answers for common questions. Cell Transport Quiz.
Беккер, спотыкаясь и кидаясь то вправо, то влево, продирался сквозь толпу. Надо идти за ними, думал. Они знают, как отсюда выбраться.
Дверь отворилась, и Сьюзан вышла в помещение шифровалки. Здесь она снова замерла. Все выглядело совсем не так, как несколько минут .
Когда Стратмор предпринимал какой-либо шаг, Танкадо стоял за сценой, дергая за веревочки. - Я обошел программу Сквозь строй, - простонал коммандер. - Но вы же не знали. Стратмор стукнул кулаком по столу.
Иногда она видела в нем что-то от Дэвида. У них было много общего: настойчивость, увлеченность своим делом, ум. Иногда ей казалось, что Стратмор без нее пропадет; ее любовь к криптографии помогала коммандеру отвлечься от завихрений политики, напоминая о молодости, отданной взламыванию шифров.
Единственная беда - Халохот глухой, с ним нельзя связаться по телефону. Недавно Стратмор сделал так, что Халохота снабдили новейшей игрушкой АНБ - компьютером Монокль. Себе Стратмор купил Скайпейджер, который запрограммировал на ту же частоту.