1. What is the primary role of membrane proteins?
A) Providing energy to the cell
B) Facilitating chemical reactions
C) Transporting molecules across the membrane
D) Maintaining the genetic material
Answer: C) Transporting molecules across the membrane
2. Which of the following is an integral protein?
A) Hemoglobin
B) Aquaporin
C) Insulin
D) Histone
Answer: B) Aquaporin
3. Peripheral proteins are located on:
A) The cytoplasmic side of the membrane
B) Embedded in the lipid bilayer
C) The extracellular side only
D) Both cytoplasmic and extracellular sides
Answer: D) Both cytoplasmic and extracellular sides
4. What type of protein forms ion channels?
A) Structural proteins
B) Integral proteins
C) Peripheral proteins
D) Enzymatic proteins
Answer: B) Integral proteins
5. Glycoproteins on the cell membrane are primarily involved in:
A) Energy production
B) Cell recognition
C) Signal transduction
D) DNA replication
Answer: B) Cell recognition
6. What is the role of carrier proteins?
A) Passive diffusion
B) Facilitated transport
C) Energy storage
D) Lipid synthesis
Answer: B) Facilitated transport
7. Which of these is an example of a channel protein?
A) ATP synthase
B) GLUT4
C) Sodium-potassium pump
D) CFTR (Cystic fibrosis transmembrane conductance regulator)
Answer: D) CFTR
8. The sodium-potassium pump is an example of:
A) Passive transport protein
B) Symporter protein
C) Antiporter protein
D) Channel protein
Answer: C) Antiporter protein
9. Which membrane proteins participate in signal transduction?
A) Receptor proteins
B) Transport proteins
C) Channel proteins
D) Enzymatic proteins
Answer: A) Receptor proteins
10. The main function of integrins is:
A) Transport of ions
B) Cell adhesion
C) Energy production
D) DNA repair
Answer: B) Cell adhesion
11. Which protein is responsible for water transport across membranes?
A) Collagen
B) Aquaporin
C) Actin
D) Tubulin
Answer: B) Aquaporin
12. A membrane protein that catalyzes chemical reactions is called:
A) Channel protein
B) Transport protein
C) Enzyme
D) Receptor protein
Answer: C) Enzyme
13. Membrane proteins are synthesized by:
A) Ribosomes on the rough endoplasmic reticulum
B) Free ribosomes in the cytoplasm
C) Mitochondria
D) Golgi apparatus
Answer: A) Ribosomes on the rough endoplasmic reticulum
14. The lipid bilayer of membranes interacts primarily with:
A) Integral proteins
B) Peripheral proteins
C) Both integral and peripheral proteins
D) Cytoskeletal proteins
Answer: A) Integral proteins
15. Which membrane protein type is involved in active transport?
A) Channel proteins
B) Carrier proteins
C) Receptor proteins
D) Peripheral proteins
Answer: B) Carrier proteins
16. Cell membrane receptors bind to:
A) DNA molecules
B) Signaling molecules like hormones
C) ATP molecules
D) Phospholipids
Answer: B) Signaling molecules like hormones
17. What is the role of clathrin in the membrane?
A) Facilitates ion transport
B) Supports vesicle formation during endocytosis
C) Anchors peripheral proteins
D) Synthesizes lipids
Answer: B) Supports vesicle formation during endocytosis
18. G-protein coupled receptors are involved in:
A) Ion transport
B) Signal transduction
C) Structural support
D) Membrane repair
Answer: B) Signal transduction
19. Which proteins mediate cell-cell communication?
A) Cadherins
B) Actin
C) Tubulin
D) ATP synthase
Answer: A) Cadherins
20. Which of the following is not a function of membrane proteins?
A) Signal transduction
B) Energy storage
C) Transport of substances
D) Cell adhesion
Answer: B) Energy storage
21. Which proteins link the cytoskeleton to the membrane?
A) Peripheral proteins
B) Integrins
C) Actin filaments
D) Glycoproteins
Answer: B) Integrins
22. Voltage-gated channels open in response to:
A) Chemical signals
B) Electrical potential changes
C) Mechanical stress
D) Temperature changes
Answer: B) Electrical potential changes
23. Ligand-gated channels are controlled by:
A) Voltage
B) Ligand binding
C) Temperature
D) ATP hydrolysis
Answer: B) Ligand binding
24. Which protein mediates cholesterol transport in cells?
A) Hemoglobin
B) LDL receptor
C) Actin
D) Tubulin
Answer: B) LDL receptor
25. What anchors peripheral proteins to the membrane?
A) Lipid bilayer
B) Hydrophobic interactions
C) Cytoskeletal elements
D) Integral proteins
Answer: D) Integral proteins
26. The primary role of connexins is:
A) DNA replication
B) Forming gap junctions for intercellular communication
C) Acting as enzymes
D) Transporting glucose
Answer: B) Forming gap junctions for intercellular communication
27. Which membrane proteins contribute to the immune response?
A) Major histocompatibility complex (MHC) proteins
B) Receptor tyrosine kinases
C) Voltage-gated ion channels
D) Integrins
Answer: A) Major histocompatibility complex (MHC) proteins
28. What is the function of spectrin in red blood cells?
A) Facilitates gas exchange
B) Provides membrane stability
C) Synthesizes hemoglobin
D) Acts as an enzyme
Answer: B) Provides membrane stability
29. Proteins involved in facilitated diffusion are:
A) Enzymes
B) Carrier and channel proteins
C) Peripheral proteins
D) Glycoproteins
Answer: B) Carrier and channel proteins
30. Which of the following is an example of an ATP-powered pump?
A) Sodium-potassium pump
B) Aquaporin
C) GLUT4 transporter
D) CFTR protein
Answer: A) Sodium-potassium pump
