Biological Membranes Lecture Review

This set of flashcards covers essential concepts about biological membranes, their composition, transport mechanisms, and the roles of various membrane components.

What is the primary structure of biological membranes composed of?

Lipids, proteins, and oligosaccharides.

What model describes the structure of biological membranes?

Fluid Mosaic Model.

What are glycoproteins?

Proteins that have oligosaccharides attached to them.

What are the two main parts of phospholipids?

Polar head and non-polar tail.

What determines the selective permeability of a membrane?

The composition and structure of the membrane.

What is the role of cholesterol in the membrane?

To maintain fluidity and stability of the membrane.

What process involves the movement of substances from high to low concentration without the use of energy?

Passive transport.

What type of transport uses proteins to facilitate the movement of molecules across the membrane?

Facilitated diffusion.

What is the difference between simple diffusion and facilitated diffusion?

Simple diffusion occurs through the phospholipid bilayer, while facilitated diffusion requires transport proteins.

Define osmosis.

The diffusion of water across a selectively permeable membrane.

What is an example of a small, non-polar molecule that can easily diffuse through the membrane?

Oxygen (O2).

What type of molecules typically require facilitated diffusion?

Polar molecules and larger molecules.

What is the energy source for active transport processes?

ATP (Adenosine triphosphate).

Differentiate between uniport, symport, and antiport mechanisms.

Uniport transports one type of molecule, symport transports two types in the same direction, and antiport transports two types in opposite directions.

What is the role of aquaporins in cells?

Facilitating the transport of water across the membrane.

How do animal cells behave in an isotonic solution?

They maintain their normal shape without net water movement.

What happens to plant cells in a hypotonic solution?

They become turgid or swollen due to water intake.

What is the primary function of membrane proteins?

Transport, communication, and structural roles.

What are integral or transmembrane proteins?

Proteins that span the membrane and are involved in transport and signaling.

What are anchored peripheral proteins?

Proteins attached to the membrane surface, often involved in signaling.

What is the main function of glycolipids in the membrane?

Cell recognition and signaling.

Define passive transport in terms of energy requirements.

It does not require cellular energy.

What does the term 'saturation of fatty acids' refer to?

The presence of double bonds in fatty acid tails affecting membrane fluidity.

What are the characteristics of small and medium-sized molecules in terms of transport?

They can often pass through membranes via simple diffusion.

What types of ions typically move through ion channels?

Charged or unchanged ions, such as Na+ and Cl-.

Why is membrane potential important for cells?

It is crucial for the function of nerve and muscle cells, affecting excitability and signaling.