Cell Transport Mechanisms

These flashcards cover key concepts related to cell transport mechanisms, including types of transport and specifics of diffusion, osmosis, and energy requirements.

What does selectively permeable mean in the context of the plasma membrane?

It means the plasma membrane controls the passage of particles in and out of the cell.

What are the three factors that determine how particles can move across the plasma membrane?

1. Size of the particle 2. Concentration gradient of the particle 3. Solubility of the particle in the phospholipid bilayer.

What is passive transport?

Passive transport mechanisms involve the movement of particles through the membrane without the use of cell energy (no ATP required).

What is simple diffusion?

Simple diffusion is the movement of particles from an area of high concentration to an area of low concentration (with/down the concentration gradient).

What factors affect the rate of diffusion?

1. Temperature 2. Particle Size 3. Concentration Gradient 4. Density of the Medium.

What is osmosis?

Osmosis is the diffusion of water across a selectively permeable membrane.

How does water move by osmosis through the plasma membrane?

Water moves through the nonpolar fatty acid tails of phospholipids and rapidly through aquaporins.

What is facilitated diffusion?

Facilitated diffusion is the movement of particles from an area of high concentration to an area of low concentration through specific protein carriers.

What are the two types of transport proteins involved in facilitated diffusion?

1. Carrier Proteins 2. Channel Proteins.

What is active transport?

Active transport is the movement of particles from an area of low concentration to an area of high concentration (against the concentration gradient) and requires energy.

How does the sodium-potassium pump function?

The sodium-potassium pump moves sodium (Na+) out of the cell and potassium (K+) into the cell, using ATP to change the shape of the transport protein.

What are the two forms of endocytosis?

1. Phagocytosis 2. Pinocytosis.

What occurs during phagocytosis?

Phagocytosis is when a cell engulfs large particles, like bacteria, by wrapping extensions of the plasma membrane around them.

What is exocytosis?

Exocytosis is the movement of large particles to the outside of the cell by fusing a vesicle with the plasma membrane.