Question

cell membrane worksheet

1. what does it mean for the cell membrane to be selectively permeable?

a. it allows all substances to freely enter and exit the cell
b. it controls what can enter and leave the cell
c. it is impermeable, preventing anything from passing through
d. it only allows water molecules to pass through

1. the cell membrane is primarily composed of:

a. proteins
b. carbohydrates
c. nucleic acids
d. phospholipids

1. phospholipids in the cell membrane have:

a. two hydrophilic heads
b. one hydrophobic head and one hydrophilic tail
c. one hydrophilic head and two hydrophobic tails
d. two hydrophobic tails and two hydrophilic heads

1. integral proteins are embedded:

a. within the lipid bilayer
b. only on the surface of the membrane
c. outside the cell
d. in the cytoplasm

1. channel proteins allow the movement of molecules:

a. actively using atp
b. passively down their concentration gradient
c. both actively and passively
d. only against their concentration gradient
protein pumps use what to actively transport ions across the membrane?
a. oxygen
b. glucose
c. water
d. atp

1. which of the following is not a role of glycolipids and glycoproteins?

a. cell recognition
b. cell signaling
c. energy production
d. immune responses

1. which type of protein changes shape to transport molecules?

a. channel proteins
b. peripheral proteins
c. integral proteins
d. carrier proteins

1. protein pumps transport ions:

a. from high to low concentration
b. from low to high concentration
c. passively
d. randomly

1. cholesterol in the cell membrane helps regulate:

a. temperature
b. fluidity
c. color
d. rigidity

1. which protein specifically transports sodium ions out of the cell?

a. potassium pump
b. glucose transporter
c. sodium - potassium pump
d. cholesterol transporter

1. the cell membrane is also known as the:

a. cell wall
b. nucleus membrane
c. cytoplasmic membrane
d. plasma membrane

1. peripheral proteins are found:

a. on the surface of the membrane
b. embedded within the lipid bilayer
c. inside the cell
d. in the nucleus

Explanation:

1. Question 1: A selectively permeable cell membrane controls substance entry/exit. Option b is correct as it's the definition. Options a (all substances), c (impermeable), d (only water) are wrong.
2. Question 2: Cell membrane is mainly phospholipids (lipid bilayer). Proteins (a) are present but not primary. Carbohydrates (b) are for cell - cell recognition. Nucleic acids (c) are in nucleus.
3. Question 3: Phospholipids have one hydrophilic head (interacts with water) and two hydrophobic tails (avoids water).
4. Question 4: Integral proteins are embedded in lipid bilayer (transmembrane). Peripheral proteins are on surface.
5. Question 5: Channel proteins allow passive transport (down concentration gradient, no ATP). Active transport uses protein pumps.
6. Question 6: Protein pumps use ATP (energy currency) for active transport (against gradient).
7. Question 7: Glycolipids/glycoproteins are for cell recognition (a), signaling (b), immune response (d). Energy production (c) is mitochondria's role.
8. Question 8: Carrier proteins change shape to transport (like glucose in). Channel proteins (a) form pores. Peripheral (b) and integral (c) have other roles.
9. Question 9: Protein pumps (active transport) move ions from low to high (needs energy). High to low (a) is passive.
10. Question 10: Cholesterol regulates membrane fluidity (prevents too rigid or fluid).
11. Question 11: Sodium - potassium pump transports sodium out (uses ATP). Potassium pump (a) is part of it but incomplete. Glucose (b) and cholesterol (d) transporters are different.
12. Question 12: Cell membrane is plasma membrane. Cell wall (a) is in plant/fungi. Nuclear membrane (b) surrounds nucleus. Cytoplasmic membrane (c) is same as plasma membrane (more formal).
13. Question 13: Peripheral proteins are on membrane surface. Integral are embedded (b).

Answer:

1. b. It controls what can enter and leave the cell
2. d. Phospholipids
3. c. One hydrophilic head and two hydrophobic tails
4. a. Within the lipid bilayer
5. b. Passively down their concentration gradient
6. d. ATP
7. c. Energy production
8. d. Carrier proteins
9. b. From low to high concentration
10. b. Fluidity
11. c. Sodium - potassium pump
12. d. Plasma membrane
13. a. On the surface of the membrane