Transport Across the Cell Membrane

Flashcards covering key concepts about membrane transport mechanisms from the lecture notes.

What forms the basic structure of the plasma membrane?

A bi-molecular layer of phospholipid molecules.

What purpose do integral proteins serve in the plasma membrane?

Act as pores, channels, or carriers to allow substances to cross the membrane.

What is the term for the process that requires energy to move solutes against a concentration gradient?

Active transport.

Name the three types of passive transport across the membrane.

1. Diffusion through lipid bilayer, 2. Diffusion through ion channels, 3. Facilitated diffusion using a carrier.

What is facilitated diffusion?

A process where a solute binds to a specific transporter on one side of the membrane and is released on the other side.

What are Gated Protein Channels?

Ion channels that can open or close, allowing faster transport than facilitated diffusion.

What is exocytosis?

Movement of large molecules out of the cell, occurring in secretory cells.

What is endocytosis?

Movement of large molecules and particles into the cell.

What are the three types of endocytosis?

1. Pinocytosis, 2. Phagocytosis, 3. Receptor-mediated endocytosis.

What molecules pass through simple diffusion and provide examples

• lipid-soluble substances

• alcohol, CO2, O2, urea, steroids

Facilitated diffusion includes of channel mediated and carrier mediated. What molecules does channel-mediated transport and what are their different types?

transports small, charged, polar ions and water

• open channels: Na+, K+

• gated channels: Ca2+, Cl-

• aquaporins: H2O

Facilitated diffusion includes of channel mediated and carrier mediated. How does carrier mediated differentiate from channel mediated

• protein carrier changes the shape of the molecule

• transports large, polar molecules

• glucose and amino acids

Contrast what types of carriers primary and secondary active transport use and how it uses ATP

• primary: uses direct ATP via transport proteins

• secondary: uses indirect ATP from ion gradient via co-transporters

List and explain the different types of co-transporters in secondary active transport

• symporters: moves in the same direction as Na+ molecule

• antiporters: moves in different directions as Na+ molecule