Cell Structure and Function

What type of transport moves molecules along their concentration gradient without requiring energy?

• Active transport
• Phagocytosis
• Pinocytosis
• Passive transport

Why is membrane fluidity essential for cellular functions?

• It prevents water loss
• It stores energy
• It synthesizes DNA
• It supports processes like secretion and endocytosis

What property of the lipid bilayer allows proteins to move laterally within the membrane?

• Rigidity of lipids
• Polarity of lipids
• Cholesterol rigidity
• Quasi-fluid nature of lipids

Which model describes the dynamic structure of the cell membrane with mobile proteins embedded in a lipid bilayer?

• Unit membrane model
• Sandwich model
• Lattice model
• Fluid mosaic model

What is the role of carrier proteins in facilitated diffusion?

• They use ATP to pump ions across the membrane
• They create channels for water movement
• They engulf large particles
• They help move polar or large molecules across the membrane without using energy