![]() Passive processes Active processes acount for the movement of fats and respiratory gases through the plasma membrane b include c incude osmosis, simple diffusion, and filtration d occur against concentration and/or electrical gradients e use hydrostatic pressure or molecular energy as the driving force For the osmometer demonstration 10. Characterize membrane transport as fully as possible by choosing all the phrases that apply and inserting their letters on the answer blanks. What determines whether a transport process is active or passive 9. Why would it be better to use an isotonics 4. ![]() Name one similarity and one difference between pinocytosis and receptor-mediated endocytosis Many classroom protocols for extracting DNA from cheek cells instruct students to swish an isotonic sports as they gently scrape the inside of the mouth with the teeth. between simple diffusion and facilitated diffusion. Name one similarity and one difference between simple diffusion and osmosits. For the osmometer demonstration (Activity 4), explain why the level of the water column rose during the laborat 11. occur against concentration and/or electrical gradients e use hydrostatic pressure or molecular energy as the driving force 10. include osmosis, simple diffusion, and filtration d. account for the movement of fats and respiratory gases through the plasma membrane b. Characterize membrane transport as fully as possible by choosing all the phrases that apply and inserting their let answer blanks Passive processes Active processes a. What determines whether a transport process is active or passive? 9. This is one example of the use of ATP in the cell: if no ATP is available, the pump won't work.Transcribed image text: 8. Imagine a pump made up of a disc (carrier protein) embedded in the cell membrane which snatches the substance in question, in this case sodium from one side of the membrane, spins (or changes shape) provided a molecule of ATP is available and discharges the sodium on the other side. The sodium/potassium pump is as an example of countertransport mechanism - the carrier protein moves three sodium ions out of the cytoplasm and moves two potassium ions into the cytoplasm. These concentrations need to be maintained for cells like muscle and nerve cells to function normally.īecause the potassium and the sodium tend to leak slowly through the cell membrane along their concentration gradients - the potassium out of the cell and the sodium into the cell, the sodium/potassium pump operates to pump sodium out of the cell against its concentration gradient and pumps potassium back into the cell. The concentration of potassium inside the cell is generally 10 to 20 times higher than the outside and the reverse is true of sodium. Temperature - an increase in temperature causes the molecules to move faster resulting in a faster rate of diffusion. Lipid solubility - lipid (fat) soluble molecules eg steroid hormones like oestrogen and testosterone can easily pass through the phospholipid bilayer Large molecules like proteins can't diffuse across the membraneĬoncentration - the greater the concentration gradient between the two sides of the membrane the greater the rate of diffusion ![]() Size of molecules - small molecules like oxygen, carbon dioxide and water can pass easily through the phospholipids in the membrane. ![]() ![]() The rate of diffusion can be affected by a number of factors such as: The greater the difference in concentration between two areas, the faster the rate of diffusion.įactors that affect the rate of diffusion At this stage there are as many molecules moving in one direction as there are in the opposite direction but there is no net movement in any direction. Diffusion is the movement of a substance from a region of high concentration to region of low concentration without the use of energy.ĭiffusion tends to move substances spontaneously down their concentration gradient until the gradient no longer exists and an equilibrium is reached. ![]()
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