BioPhysics Lecturer PDF

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What is the primary difference in electrical properties between the plasma and cytoplasm of a cell?

Plasma has more potassium ions, while cytoplasm has more sodium ions

Plasma and cytoplasm have identical ion concentrations

Plasma has more sodium ions, while cytoplasm has more potassium ions (correct)

There is no difference in electrical properties between plasma and cytoplasm.

What are the two common characteristics of the plasma and cytoplasm in terms of particle concentrations?

Electroneutrality and equal osmotic pressures (correct)

Different osmotic pressures and electroneutrality.

High permeability for ions and water.

Equal ion concentrations and different osmotic pressures

The cell membrane is least permeable to:

Water

Oxygen

Ions (correct)

Gasses

How do carrier proteins facilitate transport across the cell membrane?

Through a conformational change that transports molecules, requiring metabolic energy Signup and view all the answers

Aquaporins primarily facilitate the transport of

Water Signup and view all the answers

Which statement best describes Na-K leak channels?

They are always open, allowing easier passage of potassium ions due to their smaller hydration shell Signup and view all the answers

The selectivity of protein channels in a cell membrane is primarily determined by

The size, shape, and charge distribution of the channel's inner surface Signup and view all the answers

Which molecules pass through the lipid bilayer of the cell membrane most easily?

Small nonpolar and weakly polar molecules Signup and view all the answers

Which of the following best describes the role of transport proteins in the cell membrane?

They facilitate the passage of water and ions through the membrane Signup and view all the answers

Aquaporins are specialized for transporting:

Water molecules Signup and view all the answers

. Which of the following statements is true about protein channels in cell membranes?

Some are constantly open, while others open and close due to external stimulation Signup and view all the answers

. Na-K leak channels are characterized by

Being continuously open and allowing easy passage of potassium ions Signup and view all the answers

. Which statement correctly describes the structure of a typical cell membrane?

A double layer of lipids with embedded proteins Signup and view all the answers

The primary function of cholesterol in the cell membrane is to

Stabilize the membrane at various temperatures Signup and view all the answers

What is the significance of the cell membrane's 'fluid mosaic model'?

Suggests that the membrane components are fluid and can move laterally Signup and view all the answers

What is the primary function of voltage-dependent protein channels in cells?

They regulate the opening and closing based on membrane potential Signup and view all the answers

Facilitated diffusion differs from regular diffusion in that it

Involves transport proteins in the process Signup and view all the answers

Osmosis in cells refers to

The net diffusion of water through semipermeable membranes Signup and view all the answers

The Na-K pump is an example of

Active transport Signup and view all the answers

Ligand-gated channels in the cell membrane open in response to

The binding of specific molecules Signup and view all the answers

Facilitated diffusion is characterized by

Presence of transport proteins and movement from higher to lower concentration Signup and view all the answers

Osmosis can be best described as

Net diffusion of water through semipermeable membranes Signup and view all the answers

In active transport, how are substances moved across a cell membrane?

From an area of lower concentration to higher concentration, using ATP Signup and view all the answers

Which factor primarily determines the direction of net diffusion of molecules in a solution?

The concentration gradient of the molecules Signup and view all the answers

The osmotic pressure of a solution is directly proportional to

The molar concentration of dissolved particles Signup and view all the answers

In the context of membrane transport, 'active transport' is best described as

The transport of molecules against their concentration gradient using energy. Signup and view all the answers

What is the role of the Na-K pump in cellular function?

It helps maintain the cell’s membrane potential and regulates cell volume Signup and view all the answers

Which statement accurately describes osmotic swelling and shrinkage of cells?

all of the above Signup and view all the answers

The Nernst equation is used to calculate

The membrane potential based on ion concentration gradients Signup and view all the answers

Which process best describes the movement of glucose into a cell?

Facilitated diffusion Signup and view all the answers

What is the primary role of the Na-K pump in maintaining cell volume?

Regulating osmotic pressure Signup and view all the answers

In secondary active transport, the energy to transport molecules is derived from

The gradient created by primary active transport Signup and view all the answers

Which statement correctly describes osmotic pressures in solutions

Isoosmotic solutions have equal osmotic pressures Signup and view all the answers

How does the concentration of ions inside and outside a cell primarily affect the membrane potential?

The ratio of ion concentrations inside and outside the cell directly influences the membrane potential Signup and view all the answers

The Goldman equation is used to calculate

The membrane potential considering multiple ion types Signup and view all the answers

What is a primary function of secondary active transport in cells?

To transport molecules using the energy stored in ion gradients Signup and view all the answers

Which of the following best describes the role of ion channels in the cell membrane?

They facilitate the passive transport of specific ions Signup and view all the answers

In the context of cell membrane transport, what does 'selectivity' refer to?

The preference of transport proteins for specific ions or molecules. Signup and view all the answers

Which statement best describes the effect of membrane potential on the movement of ions across the cell membrane?

Membrane potential influences the directional movement of ions based on their charge Signup and view all the answers

The process of active transport in cells is characterized by

Transport of substances against their concentration gradient using cellular energy. Signup and view all the answers

Osmotic pressure in cells is most directly affected by

The concentration of non-permeable solutes Signup and view all the answers

Which of the following is true about facilitated diffusion?

) It involves transport proteins and moves substances from higher to lower concentration Signup and view all the answers

In secondary active transport, what is the relationship between the transport of sodium and the co-transported substance?

Sodium and the co-transported substance move in the same direction across the membrane. Signup and view all the answers

Which statement is true about the Na-K pump's role in nerve signal conduction?

It maintains the concentration gradients essential for action potential propagation. Signup and view all the answers

In the context of membrane transport, what does 'saturation kinetics' refer to?

The rate of transport does not increase with increased substrate concentration Signup and view all the answers

Which factor primarily influences the movement of ions due to the electric field across a cell membrane?

The intensity of the electric field across the membrane. Signup and view all the answers

The concept of 'electrochemical equilibrium' in cells refers to

A state where there is no net movement of ions across the membrane Signup and view all the answers

What does the 'reflection coefficient' in membrane transport indicate?

The proportion of a solute's osmotic pressure contributing to net water flow Signup and view all the answers

What effect does the Na-K pump have on the concentration of ions inside the cell?

It decreases sodium ion concentration and increases potassium ion concentration Signup and view all the answers

Secondary active transport is distinguished by

Utilizing energy from ion gradients created by primary active transport Signup and view all the answers

In facilitated diffusion, what role do transport proteins play?

They provide a passage through the membrane for specific molecules. Signup and view all the answers

The concept of 'osmotic pressure' is best explained as

The pressure required to prevent the flow of water across a semipermeable membrane. Signup and view all the answers

What is the primary factor determining the direction of water movement in osmosis?

The concentration of solutes that cannot cross the membrane Signup and view all the answers

In terms of membrane transport, what is the significance of the 'reflection coefficient'?

It represents the degree of solute permeability through the membrane Signup and view all the answers

Which ions primarily contribute to the resting membrane potential in neurons?

Potassium and sodium ions Signup and view all the answers

What is the primary purpose of the Na-K pump in cellular activity?

Maintaining concentration gradients of sodium and potassium ions. Signup and view all the answers

Which process describes the movement of water from an area of low solute concentration to an area of high solute concentration?

Osmosis. Signup and view all the answers

The term 'electrogenic transport' refers to

Transport processes that contribute to the generation of a membrane potential Signup and view all the answers