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TLS Online TPP Program

#Question id: 14754

Plant cells have several internal compartments, each of which can differ in its ionic composition. The cytosol and the vacuole are the most important intracellular compartments that determine the ionic relations of plant cells, Ion concentrations in the cytosol and the vacuole are controlled by passive (dashed arrows) and active (solid arrows) transport processes
  

Which of the following statement INCORRECT from the above figure;

#Unit 6. System Physiology – Plant
  1. Potassium is accumulated passively by both the cytosol and the vacuole, except when extracellular K+ concentrations are very low, in which case it is taken up actively
  2. All the anions are taken up actively into the cytosol.
  3. Calcium is actively transported out of the cytosol at both the cell membrane and the vacuolar membrane, which is called the tonoplast
  4. Sodium is pumped passively out of the cytosol into the extracellular spaces and vacuolar membrane
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TLS Online TPP Program

#Question id: 379

#Unit 1. Molecules and their Interaction Relevant to Biology

A compound has a pKa of 7.4. To 100 mL of a 1.0 M solution of this compound at pH 8.0 is added 30 mL of 1.0 M hydrochloric acid. The resulting solution is pH:
TLS Online TPP Program

#Question id: 380

#Unit 1. Molecules and their Interaction Relevant to Biology

The Henderson-Hasselbalch equation:
TLS Online TPP Program

#Question id: 381

#Unit 1. Molecules and their Interaction Relevant to Biology

Consider an acetate buffer, initially at the same pH as its pKa (4.76). When sodium hydroxide (NaOH) is mixed with this buffer, the:
TLS Online TPP Program

#Question id: 382

#Unit 1. Molecules and their Interaction Relevant to Biology

The molar ratio of sodium acetate to acetic acid in a buffer solution with a pH OF 5.76 is 10:1. Assuming the total buffer concentration is 2.2 X 10-2 mol/L, how many grams of sodium acetate (m.w. 82) and how many grams of acetic acid (m.w. 60) should be used in preparing a litre of the solution?
TLS Online TPP Program

#Question id: 383

#Unit 1. Molecules and their Interaction Relevant to Biology

Three buffers are made by combining a 1 M solution of acetic acid with a 1 M solution of sodium acetate in the ratios shown below

1 M acetic acid              

1 M sodium acetate  

Buffer 1: 10 mL

 90 mL

Buffer 2: 50 mL

50 mL

Buffer 3: 90 mL

10 mL

 Which of these statements is true of the resulting buffers?
TLS Online TPP Program

#Question id: 384

#Unit 1. Molecules and their Interaction Relevant to Biology

A solution was prepared by dissolving 0.02 moles of acetic acid (HOAc; pKa = 4.8) in water to give 1 liter of solution. What is the pH? To this solution was then added 0.008 moles of concentrated sodium hydroxide (NaOH). What is the new pH? (In this problem, you may ignore changes in volume due to the addition of NaOH).