Cell Membrane Transport

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What is passive transport?

Passive transport is the movement of substances across a cell membrane without the need for energy input from the cell.

What is diffusion?

Diffusion is the passive movement of particles from an area of high concentration to an area of low concentration.

What is facilitated diffusion?

Facilitated diffusion is a type of passive transport that uses transport proteins to move substances across the cell membrane.

Define osmosis.

Osmosis is the diffusion of water molecules across a semi-permeable membrane from low solute concentration to high solute concentration.

What is active transport?

Active transport is the movement of substances across a cell membrane against a concentration gradient, requiring energy (ATP).

What role does the sodium-potassium pump play in cells?

The sodium-potassium pump is an active transport mechanism that moves sodium out of and potassium into cells, essential for cell function.

What is endocytosis?

Endocytosis is a process where cells engulf external substances, bringing them into the cell in vesicles.

Differentiate between phagocytosis and pinocytosis.

Phagocytosis is the engulfing of large particles, while pinocytosis is the ingestion of liquid or small particles.

Explain exocytosis.

Exocytosis is the process of vesicles fusing with the plasma membrane to release their contents outside the cell.

What is meant by membrane permeability?

Membrane permeability refers to the ability of the membrane to allow substances to pass through it.

How do carrier proteins function in cell transport?

Carrier proteins facilitate the transport of specific substances across the cell membrane by undergoing a change in shape.

What is the role of channel proteins in the cell membrane?

Channel proteins provide passageways for molecules and ions to pass through a membrane, without energy input.

Define cell membrane potential.

Membrane potential is the voltage difference across a cell's membrane.

What is the purpose of the lipid bilayer in cell membranes?

The lipid bilayer gives the cell membrane structural integrity and controls the passage of substances into and out of the cell.

Explain how temperature affects cell membrane fluidity.

Increased temperature enhances fluidity, whereas decreased temperature reduces it, affecting membrane permeability and protein function.

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