All flashcards
Flashcard 1: Identify the transport type: oxygen moves into a cell from higher outside concentration to lower inside concentration.
Answer: Simple diffusion (passive transport). Small gas molecules diffuse freely without proteins or energy.
Flashcard 2: What is a carrier protein, in terms of membrane transport function?
Answer: A protein that binds a substance and changes shape to move it. Undergoes conformational change to transport molecules.
Flashcard 3: What is a channel protein, in terms of membrane transport function?
Answer: A protein pore that lets specific ions or water pass. Forms tunnel for passive movement of specific molecules.
Flashcard 4: Which cellular molecule usually provides the energy for active transport?
Answer: ATP. Cell's energy currency powers uphill molecular transport.
Flashcard 5: What type of transport moves substances from low to high concentration and requires energy?
Answer: Active transport. Uses energy to pump molecules against concentration gradient.
Flashcard 6: Which direction does water move by osmosis relative to solute concentration?
Answer: Toward the side with higher solute concentration. Water dilutes concentrated solutions to reach equilibrium.
Flashcard 7: What is the basic structure of the cell membrane that forms a barrier?
Answer: Phospholipid bilayer. Two layers of phospholipids create the membrane's foundation.
Flashcard 8: What is the main structural model that explains cell membrane organization?
Answer: Fluid mosaic model. Describes membrane as flexible with proteins embedded in lipids.
Flashcard 9: What property of the cell membrane describes allowing some substances through but not others?
Answer: Selective permeability (semipermeable). Allows only certain molecules through while blocking others.
Flashcard 10: Which molecule provides energy for many active transport processes?
Answer: ATP. The cell's energy currency powers transport pumps.
Flashcard 11: What is diffusion across a membrane called when it requires no energy from the cell?
Answer: Passive transport. Molecules move naturally down their concentration gradient.
Flashcard 12: What is active transport?
Answer: Movement against the gradient using energy (ATP). Pumps molecules from low to high concentration areas.
Flashcard 13: What is endocytosis?
Answer: Cell takes in substances by forming membrane vesicles. Membrane pinches inward to engulf external materials.
Flashcard 14: Identify the transport type: a white blood cell engulfs a bacterium into a vesicle.
Answer: Endocytosis (phagocytosis). Cell eating - membrane surrounds and engulfs large particles.
Flashcard 15: Identify the transport type: a cell uses ATP to pump extNa+ out where extNa+ is already higher outside.
Answer: Active transport. Energy required to pump ions against concentration gradient.
Flashcard 16: Identify the transport type: glucose crosses the membrane through a specific protein with no ATP used.
Answer: Facilitated diffusion. Protein channels help polar molecules move down gradient.
Flashcard 17: Which part of a phospholipid faces water: the head or the tails?
Answer: The hydrophilic head faces water. Polar heads are attracted to water molecules.
Flashcard 18: Which part of a phospholipid avoids water: the head or the tails?
Answer: The hydrophobic fatty acid tails avoid water. Nonpolar tails repel water, forming the membrane's interior.
Flashcard 19: Identify the transport type: oxygen moves directly through the bilayer from high to low concentration.
Answer: Simple diffusion (passive transport). Small, nonpolar molecules cross the lipid bilayer freely.
Flashcard 20: What is exocytosis?
Answer: Cell releases substances when vesicles fuse with the membrane. Vesicles merge with membrane to expel contents outside.
Flashcard 21: What phrase describes the cell membrane property of allowing some substances through but not others?
Answer: Selectively permeable (semipermeable). Like a filter that blocks some molecules while letting others pass.
Flashcard 22: What type of membrane protein provides a passageway for specific ions or molecules?
Answer: Channel protein. Acts like a tunnel for specific ions or small molecules.
Flashcard 23: What type of membrane protein changes shape to move a substance across the membrane?
Answer: Carrier protein. Binds and releases molecules through conformational changes.
Flashcard 24: What is the main function of the cell membrane in controlling cell contents?
Answer: It selectively regulates what enters and leaves the cell. Acts as a gatekeeper, maintaining cell homeostasis.
Flashcard 25: Which option describes facilitated diffusion: movement with or against the gradient?
Answer: With the gradient (high to low) using a membrane protein. Proteins help large or polar molecules cross without energy.
Flashcard 26: What term describes a concentration difference across a membrane?
Answer: Concentration gradient. The difference drives passive transport processes.
Flashcard 27: What is the cell membrane mainly made of that forms a barrier between cell and environment?
Answer: A phospholipid bilayer with embedded proteins. Proteins help transport specific molecules across the lipid barrier.
Flashcard 28: What is osmosis?
Answer: Diffusion of water across a selectively permeable membrane. Water moves to balance solute concentrations.
Flashcard 29: What is diffusion?
Answer: Movement from high concentration to low concentration. Molecules naturally spread out to reach equilibrium.
Flashcard 30: Which type of transport uses a membrane protein to move molecules down their concentration gradient?
Answer: Facilitated diffusion. Proteins help larger molecules cross without using energy.