Exercise 1: Activity 1-5

The driving force for diffusion is a. ATP b. Kinetic energy of molecules c. Membrane transport protein d. Dialysis membrane

In diffusion, molecules move a. from high to low concentration b. from low to high concentration c. from either high or low concentration d. against concentration gradient

Which of the following dialysis membranes has the largest pore size? a. 20 MWCO b. 50 MWCO c. 100 MWCO d. 200 MWCO

Avogadro's number is a constant for the number of a. moles b. molecules c. milliliters d. atoms

Predict Question: 1. The molecular weight of urea is 60.07. Do you think urea will diffuse through the 20 MWCO membrane?

Predict Question: 2. Recall that glucose is a monosaccharide, albumin is a protein with 607 amino acids, and the average molecular weight of a single amino acid is 135 g/mole. Which of the following will be able to diffuse through the 200 MWCO membrane?

The reason sodium chloride didn't diffuse left to right is that

Glucose is a six-carbon sugar. Albumin is a protein with 607 amino acids. The average molecular weight of a single amino acid is 135 g/mole. There is no reason to run these solutes at the 20 MWCO because

The rate of diffusion for urea

The effect of increasing the concentration of sodium chloride from 9 mM to 18 mM in the left beaker was to a. decrease b. increase c. no change

Describe the difference between the rate of diffusion seen for sodium and urea.

Which of the following solutes did not pass through any of the membranes?

When diffusion stops, we say the solution has reached

Molecules need a carrier protein to help them move across a membrane because

Which of the following is true of facilitated diffusion?

Predict Question: 1. What effect do you think increasing the number of protein carriers will have on the glucose transport rate?

Which of the following would not affect the rate of facilitated diffusion? a. amount of intracellular ATP b. concentration of solutes c. number of membrane carriers d. gradient steepness

Predict Question: 2. What effect do you think adding Na+ Cl- will have on the glucose transport rate?

What happened to the glucose transport rate when the glucose concentration was increased from 2 mM to 8 mM?

Describe the conditions that resulted in the fastest rate of glucose transport.

Why do you think equilibrium wasn't reached?

Examples of solutes that might require facilitated diffusion include a. glucose b. sodium c. potassium d. all of the above

What variable(s) increased the rate of facilitated diffusion of glucose? a. increasing its concentration b. increasing number of membrane carriers c. adding sodium chloride d. both a and b

For facilitated diffusion, increasing the concentration of glucose on one side of the membrane is the same as a. making the concentration gradient flatter b. making the concentration gradient steeper c. adding ATP d. changing the direction of diffusion

When all of the membrane carriers are engaged, or busy, we say they are a. saturated b. satiated c. inhibited d. selected

Na+ Cl- had no effect on glucose transport because a. glucose and sodium are co-transported b. sodium isn't required for glucose transport in the simulation c. sodium is actively transported in the simulation d. the membrane proteins were saturated

The movement of sodium and potassium maintained by the Na+ -K+ pump

The sodium-potassium pump is classified as a(n)

The sodium-potassium pump moves _____ sodium ions and _____ potassium ions simultaneously.

Solutes that require active transport for movement might be too large to pass or might be

Predict Question: 1. What do you think will result from these experimental conditions?

Predict Question: 2. Do you think the addition of glucose carriers will affect the transport of sodium or potassium?

Why did the sodium transport stop before the transport was completed?

Why was the equilibrium for the solutes reached earlier?

What happened when you increased the amount of ATP dispensed with the same concentration of sodium and potassium on either side of the membrane?

At what concentration of ATP were the sodium and potassium maximally transported?

What was the effect of adding more Na+ -K+ pumps to the simulated cell?

Describe the effect of adding glucose carriers to the sodium and potassium transport.