From audio: Transporters, Channels, Pumps 1&2

This set of flashcards covers key concepts from Dr. Bruce Siegels' lecture on the physiological relevance of transporters and channels, focusing specifically on the distribution of electrolytes, plasma membrane structure, types of transport mechanisms, and the roles of active and passive transport.

What are the major electrolytes involved in physiological systems?

Sodium, potassium, chloride, bicarbonate, calcium, and impermeable anions.

What is the primary function of the plasma membrane?

To separate the internal environment of the cell (cytoplasm) from the external fluid.

What is simple passive diffusion?

The movement of molecules across the plasma membrane without the need for transport proteins, from a high concentration to a low concentration.

How is the movement of sodium ions characterized in terms of cell concentration?

Sodium ions are much more concentrated outside the cell, with a ratio of approximately 10 to 1 compared to inside.

What characterizes potassium ion distribution across the plasma membrane?

Potassium has a much higher concentration inside the cell, with a ratio of about 25 times greater than outside.

Explain the role of the lipid bilayer in the plasma membrane.

It acts as a barrier, preventing molecules from easily moving between the intracellular and extracellular environments.

What components comprise the plasma membrane?

Lipids (50%), proteins (40%), and carbohydrates (10%).

How do channels facilitate ion movement across the plasma membrane?

Channels allow the movement of specific ions or water through a selectively permeable pathway across the membrane.

What distinguishes primary active transport from secondary active transport?

Primary active transport directly uses ATP to move substances against a concentration gradient, while secondary active transport relies on the gradient created by primary active transport.

What is facilitated diffusion?

The process of transporting molecules across the plasma membrane via a specific carrier protein down their concentration gradient without the use of energy.

What happens during the sodium-potassium ATPase process?

Three sodium ions are pumped out of the cell for every two potassium ions pumped in, using ATP for energy.

Describe the difference between ligand-gated and voltage-gated channels.

Ligand-gated channels open or close in response to the binding of a chemical messenger, while voltage-gated channels respond to changes in membrane potential.

What is the main function of primary active transport?

To maintain ion gradients across the cell membrane, which allows for various cellular functions including bioelectricity and osmotic stability.

What is the source of energy for active transport processes?

The hydrolysis of ATP (adenosine triphosphate) provides the energy necessary for active transport.

What role do impermeable anions play within the cell?

They contribute to the negative charge inside the cell, maintaining an electrochemical gradient.

What is secondary active transport, and how does it work with sodium-glucose transport?

It utilizes sodium's concentration gradient, created by primary active transport, to co-transport glucose into the cell against its concentration gradient.