Mechanisms of Transport - AP Biology
- What is antiport?
- Transport of two substances in opposite directions across a membrane. One substance enters while another exits the cell.
- What is cotransport?
- The coupled transport of two substances across a membrane. One substance's gradient drives another's transport.
- Name a protein involved in active transport.
- Sodium-potassium pump. Maintains cellular ion gradients essential for nerve function.
- How does temperature generally affect diffusion rate?
- Higher temperature increases diffusion rate. Increased kinetic energy accelerates molecular movement.
- What is the function of glycoproteins in the cell membrane?
- Cell recognition and communication. Sugar chains on proteins enable cellular identification.
- What is osmosis?
- The diffusion of water across a selectively permeable membrane. Water moves to equalize solute concentrations.
- What type of transport uses energy: endocytosis or facilitated diffusion?
- Endocytosis. Endocytosis requires ATP for membrane deformation and vesicle formation.
- What is the meaning of 'hypertonic' in terms of solution concentration?
- A solution with a higher solute concentration than another. Higher solute concentration creates osmotic pressure.
- What is the primary function of the cell membrane?
- To regulate the movement of substances in and out of the cell. This selective permeability controls cellular homeostasis.
- Which transport mechanism involves vesicles?
- Endocytosis and exocytosis. These processes transport large materials through membranes.
- What is facilitated diffusion?
- Passive transport using proteins to move substances across the membrane. Enables transport of polar molecules that can't cross lipid bilayer.
- What is membrane potential?
- The voltage difference across a cell's plasma membrane. Results from unequal ion distribution across membrane.
- What is the role of cholesterol in the cell membrane?
- To maintain fluidity and stability of the membrane. Modulates membrane fluidity at different temperatures.
- Explain the term 'concentration gradient'.
- The difference in concentration of a substance across a space. This drives the direction of passive transport.
- What is the primary function of the sodium-potassium pump?
- To maintain the electrochemical gradient in cells. Essential for nerve impulses and cellular signaling.
- Identify the main component of the cell membrane.
- Phospholipids. These amphipathic molecules form the bilayer structure.
- Which molecule provides energy for active transport?
- ATP (adenosine triphosphate). Hydrolysis of ATP releases energy for cellular work.
- Which type of molecule generally requires facilitated diffusion?
- Polar or charged molecules. These cannot cross the lipid bilayer directly.
- What role do aquaporins play in cells?
- They facilitate water transport across cell membranes. These protein channels specifically transport water molecules.
- What does the term 'selectively permeable' mean?
- Allowing certain substances to pass through while blocking others. Membrane proteins determine this selective passage.
- Identify a type of protein used in facilitated diffusion.
- Channel proteins. These form specific pathways for ion movement.
- Define exocytosis.
- The process of expelling materials from the cell via vesicles. Vesicles fuse with membrane to release contents.
- What is passive transport?
- Movement of substances across the membrane without energy input. Driven by concentration gradients and kinetic energy.
- What is pinocytosis?
- A type of endocytosis involving the ingestion of liquid into the cell. Literally means 'cell drinking' for fluid uptake.
- Identify the water channel proteins in the cell membrane.
- Aquaporins. These specialized channels transport only water molecules.
- What is the key difference between active and passive transport?
- Active transport requires energy, passive does not. Energy requirement distinguishes these transport types.
- What is the role of carrier proteins?
- To transport substances across the cell membrane. They undergo conformational changes to move substances.
- What is a hypotonic solution?
- A solution with a lower solute concentration than another. Lower solute concentration causes water to enter.
- Define diffusion.
- The movement of particles from high to low concentration. This process continues until equilibrium is reached.
- What is symport?
- Transport of two substances in the same direction across a membrane. Both substances move together in same direction.
- What is active transport?
- Movement of substances against their concentration gradient using energy. ATP hydrolysis powers this uphill transport process.
- Identify the gradient used in chemiosmosis.
- Proton gradient. This electrochemical gradient drives ATP synthesis.
- What is phagocytosis?
- A type of endocytosis involving the ingestion of large particles. Literally means 'cell eating' for particle uptake.
- What is an isotonic solution?
- A solution with equal solute concentration to another. Equal concentrations prevent net water movement.
- Which process requires ATP: diffusion or active transport?
- Active transport. Diffusion uses no energy, active transport requires ATP.
- What role do glycoproteins play in cell membranes?
- They assist in cell-cell recognition. Carbohydrate markers enable immune system recognition.
- What is the process of removing waste from a cell called?
- Exocytosis. Vesicles transport waste to the cell surface.
- Identify the term for the movement of ions across a membrane.
- Ion transport. Charged particles require specific protein channels.
- What is the function of the proton pump in cells?
- To transport protons across membranes, creating a gradient. Essential for chemiosmosis in cellular respiration.
- Describe endocytosis.
- The process of taking in materials by engulfing them in the cell membrane. The cell membrane invaginates to form vesicles.