Concept explainers
To explain:
Draw and label model of plasma membrane of a cell that is placed in a solution with concentrations of calcium ion and lactose that are greater than those on the inside of the cell, and use arrows to show the relevant gradients and the activity of the following membrane proteins:
a pump that exports protons;
a calcium channel; and
a lactose carrier.
Introduction:
The plasma membrane is composed of a phospholipid bilayer, which is selectively permeable and regulates the entry and exit of the cell. The different solute concentrations outside and inside the cell create a concentration gradient. The solutes move from regions of high concentration to regions of low concentration during concentration gradient.
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Biological Science (7th Edition)
- Consider the artificial cell experiment below: Lactose 2.0 M Ca+ = 0.4 M The ion channels in the membrane will allow Ca+ to pass freely, but nothing else. The starting conditions for the experiment are shown. Rewrite the following statement to make it correct: "The calcium ions will move across the membrane because ion channels allow active transport." Lactose = 0.1 M Ca+ = 3.0 M Edit View Insert Format Tools Table 12pt ✓ Paragraph :arrow_forwardBy providing examples, explain what roles molecular motors play in the transport of vesicles and the intercellular organisation of organelles.arrow_forwardSuppose calcium ion is maintained within an organelle at a concentration1000 times greater than outside the organelle (T = 37 °C). Assuming the membrane is permeable to Ca2+, what is the contribution of Ca2+ to the membrane potential? Which side of the organelle membrane is positive, and which is negative?arrow_forward
- Below is a picture of the sodium-potassium (Na*/K*) pump. Na Higher concentration Lower concentration Na* ATP protein pump K* Lower concentration Higher concentration (i) When sodium and potassium ions move across the membrane using the Na*/K* pump, they are using which type of cell membrane transport? ( (ii) In your own words, describe the process by which sodium ions cross the membrane using the Na*/K* pump. Incorporate into your answer all of the following terms; higher concentration, lower concentration, ATP, concentration gradient, Na*/K* pump. (iii) In your own words, describe the process by which potassium ions cross the membrane using the Na*/K* pump. Incorporate into your answer all of the following terms; higher concentration, lower concentration, ATP, concentration gradient. Na /K pump Edit View Insert Format Tool 12pt Paragrapharrow_forwardThis graph shows the electrical charges of the cytosol at one spot along an axon or muscle cell. a) Even though the charges are the same at steps 3 and 6, explain the situation with the ions on either side of the membrane. I am not looking for a vocabulary term here, just a simple explanation in normal words. b) At step 6, this spot in the cell is not ready to conduct another action potential/impulse. What has to happen to get it ready again- and how is this done?arrow_forwardSuppose calcium ion is maintained within an organelle at a concentration 1000 times greater than outside the organelle (T = 37 °C). Assuming the membrane is permeable to Ca2+, what is the contribution of Ca2+ to the membrane potential? Which side of the organelle membrane is positive, and which is negative?arrow_forward
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