Cell Membrane Transport Worksheet

Question 1

What is a selectively permeable membrane?

Answer 1

the membrane only lets certain substances into the cell

Question 2

What is solute?

Answer 2

substance being dissolved

Question 3

What is diffusion?

Answer 3

random movement of particles so naturally flow down the concentration gradient (flow from high concentration to low concentration)

Question 4

What is osmosis?

Answer 4

diffusion of water across a semipermeable membrane (Free flow of water molecules)

Question 5

What does it mean when something is isotonic?

Answer 5

equal amount of water outside of the cell and inside, no net gain/loss of water

Question 6

What does it mean when something is hypotonic?

Answer 6

higher concentration of water in the cell, so more water moves in, causing the cell to swell/burst

Question 7

What does it mean when something is hypertonic?

Answer 7

higher concentration of water outside of the cell, so water wants to leave the cell causing it to shrink/shrivel

Question 8

Describe how a channel protein moves solute across the membrane

Answer 8

by forming a hydrophilic pore through the hydrophobic phospholipid bilayer, allowing specific ions or small polar molecules to passively diffuse across the membrane without directly contacting the lipid interior

Question 9

Describe how a carrier protein moves solute across the membrane

Answer 9

binding specifically to the solute on one side of the membrane, then changing its shape to transport the solute to the other side, where it is released

Question 10

Distinguish between active (primary) transport and secondary

Answer 10

primary active transport that uses ATP, and secondary active transport that uses an electrochemical gradient

Question 11

1) What is an electrochemical gradient? 2) How does this affect how molecules move?

Answer 11

1) concentration gradient and charged gradient that determines where molecules go
2) by determining the net direction of an ion’s movement across a cell membrane, taking into account both the concentration gradient and the electrical gradient across the membrane

Question 12

1) What types of molecules are transported in simple diffusion?
2) Does simple diffusion require a carrier or channel protein?
3) Does simple diffusion require an additional energy source?
4) Do any molecules travel against their concentration gradient or electrochemical gradients?

Answer 12

1) small, uncharged, nonpolar molecules
2) no
3) no
4) no

Question 13

1) What types of molecules are transported in facilitated diffusion?
2) Does facilitated diffusion require a carrier or channel protein?
3) Does facilitated diffusion require an additional energy source?
4) Do any molecules travel against their concentration gradient or electrochemical gradients?

Answer 13

1) large, charged, polar molecules
2) yes
3) no
4) no

Question 14

1) What types of molecules are transported in primary active transport?
2) Does primary active transport require a carrier or channel protein?
3) Does primary active transport require an additional energy source?
4) Do any molecules travel against their concentration gradient or electrochemical gradients?

Answer 14

1) large, charged, polar molecules
2) yes, carrier
3) yes
4) yes

Question 15

1) What types of molecules are transported in secondary active transport?
2) Does secondary active transport require a carrier or channel protein?
3) Does secondary active transport require an additional energy source?
4) Do any molecules travel against their concentration gradient or electrochemical gradients?

Answer 15

1) glucose, amino acids
2) yes, carrier
3) no
4) yes

Question 16

What are the 6 steps involved in ion transport using the sodium-potassium pump?

Answer 16

3 sodium ions enter the pump, ATP binds to the pump and releases a phosphate group turning into ADP, the pump closes to the interior, pump reopens and changes shape to release 3 sodium ions and lets in 2 potassium ions, the pump closes to the exterior, and reopens releasing the potassium ions and the process repeats