Cell Biology: Plasma Membrane Functions

<p>It provides a physical barrier that contains cellular contents, and creates a specific micro-environment. (B)</p> Signup and view all the answers

<p>The plasma membrane regulates movement of substances, controlling the composition of both ICF and ECF. (A)</p> Signup and view all the answers

<p>To enable cells to organize into appropriate groupings. (A)</p> Signup and view all the answers

<p>Collagen (C)</p> Signup and view all the answers

<p>To allow tissues to stretch and then recoil. (A)</p> Signup and view all the answers

<p>Tight junctions (D)</p> Signup and view all the answers

<p>It is selectively permeable, allowing some substances to pass while preventing others. (B)</p> Signup and view all the answers

<p>Oxygen (B)</p> Signup and view all the answers

<p>Granulation (C)</p> Signup and view all the answers

<p>To facilitate cell adhesion and position. (C)</p> Signup and view all the answers

<p>A substance that cannot cross the membrane by any means. (B)</p> Signup and view all the answers

<p>Lipid solubility and particle size. (A)</p> Signup and view all the answers

<p>Nonpolar and lipid soluble. (B)</p> Signup and view all the answers

<p>Charged particles like ions and polar molecules. (B)</p> Signup and view all the answers

<p>Diffusion down a concentration gradient. (C)</p> Signup and view all the answers

<p>Oxygen (B)</p> Signup and view all the answers

<p>Active transport requires cellular energy, while passive does not. (B)</p> Signup and view all the answers

<p>It is a critical passive process that all cells use for survival. (D)</p> Signup and view all the answers

<p>The cell will shrink as water diffuses out of it. (D)</p> Signup and view all the answers

<p>Carrier-mediated transport that does not require cellular energy. (C)</p> Signup and view all the answers

<p>Facilitated diffusion using carrier proteins. (C)</p> Signup and view all the answers

<p>Facilitated diffusion does not require energy; active transport requires cellular energy. (A)</p> Signup and view all the answers

<p>Water diffuses into the cell, causing it to swell. (B)</p> Signup and view all the answers

<p>Vesicular transport. (D)</p> Signup and view all the answers

<p>Both require carrier proteins as part of the process. (A)</p> Signup and view all the answers

<p>By changing its shape to expose binding sites to both sides of the membrane. (A)</p> Signup and view all the answers

<p>They facilitate the movement of water-soluble substances across the membrane through conformational changes. (D)</p> Signup and view all the answers

<p>Facilitated diffusion (A)</p> Signup and view all the answers

<p>Channel proteins are always open, while carrier proteins must change conformation. (D)</p> Signup and view all the answers

<p>The limited number of carrier proteins available in the membrane. (D)</p> Signup and view all the answers

<p>Each carrier protein will only transport specific substances or a few closely related compounds. (D)</p> Signup and view all the answers

<p>It requires direct input of energy in the form of ATP. (D)</p> Signup and view all the answers

<p>Carriers need to undergo a conformational change, but channels do not. (B)</p> Signup and view all the answers

<p>Competition (C)</p> Signup and view all the answers

<p>Endocytic vesicle fusion with the plasma membrane (B)</p> Signup and view all the answers

<p>A separation of opposite charges across the membrane. (C)</p> Signup and view all the answers

<p>The charge separation is greater. (C)</p> Signup and view all the answers

<p>It makes a small direct contribution to the resting membrane potential. (A)</p> Signup and view all the answers

<p>Passive diffusion of K+ ions (D)</p> Signup and view all the answers

<p>The intracellular space is negatively charged compared to the outside. (B)</p> Signup and view all the answers

<p>K+ (C)</p> Signup and view all the answers

<p>Through protein channels specific to each ion (C)</p> Signup and view all the answers

<p>The activity of the Na+-K+ pump (D)</p> Signup and view all the answers

<p>The inside of the cell is more negative than the outside. (D)</p> Signup and view all the answers

The plasma membrane provides a physical barrier for cells, controlling what enters and leaves.

The lipid bilayer forms the foundation of the plasma membrane, acting as a selective barrier.

The plasma membrane is composed of a lipid bilayer, proteins, and carbohydrates, each contributing to its function.

Proteins embedded in the plasma membrane facilitate transport, communication, and structural support.

Cells can adhere to each other through structures like tight junctions, desmosomes, and gap junctions.

A type of cell junction that acts like molecular Velcro, binding adjacent cells together and preventing leakage between them.

A specialized cell junction that forms channels between cells, allowing ions and small molecules to pass for intercellular communication.

A substance that promotes cell adhesion, holding cells in position within the extracellular matrix.

A type of protein fiber in the extracellular matrix that provides tensile strength, making tissues flexible and resistant to stretching.

A type of protein fiber in the extracellular matrix that allows tissues to stretch and then recoil, providing elasticity.

The biological glue that binds cells together, consisting of interconnected protein fibers and ground substance.

The movement of substances across the cell membrane without requiring energy, driven by concentration gradients or pressure differences.

The movement of substances across the cell membrane that requires energy, going against concentration gradients.

Materials move across the cell membrane without assistance from the cell. It's a passive process where substances follow natural gradients.

The movement of a substance across a membrane from a region of higher concentration to a region of lower concentration. This is a passive process driven by the concentration difference.

The difference in concentration of a substance between two areas. It's the driving force for diffusion. The steeper the gradient, the faster diffusion occurs.

When a substance crosses the cell membrane due to the differences in electrical charge on either side of the membrane. It's a passive process.

It's the tendency of a substance to dissolve in a lipid bilayer. Lipid soluble substances can easily pass through the cell membrane.

The cell spends energy to move substances across the membrane, going against their natural concentration or electrical gradient.

Substances can pass through the membrane in passive transport. These substances are highly soluble in lipids.

Substances like Na+ ions, glucose, and proteins cannot dissolve in lipids and need assistance to cross the membrane.

Movement of substances across cell membranes without the use of cellular energy. Examples include diffusion, osmosis, and filtration.

Movement of water across a semipermeable membrane from an area of high water concentration to an area of low water concentration.

A solution that has the same concentration of solutes as the cell's cytoplasm. Water moves equally in and out of the cell, maintaining its volume.

A solution that has a lower concentration of solutes than the cell's cytoplasm. Water moves into the cell, causing it to swell.

A solution that has a higher concentration of solutes than the cell's cytoplasm. Water moves out of the cell, causing it to shrink.

A type of membrane transport that uses carrier proteins to move molecules across the membrane. It can be either facilitated diffusion or active transport.

A form of carrier-mediated transport that moves molecules across the membrane down their concentration gradient. It does not require energy.

A type of passive transport where a substance moves across a membrane with the help of a protein carrier, but still following the concentration gradient, without requiring energy.

The specific protein involved in facilitated diffusion that binds to a substance and helps its movement across the membrane, changing its conformation during the process.

A type of membrane transport protein that allows specific substances to move across the membrane via a continuous passage, unlike carrier proteins.

The maximum rate at which a substance can be transported by a carrier protein, determined by the number of available binding sites on the carrier.

The phenomenon where multiple substances compete for binding to the same carrier protein, potentially slowing down the transport of any one of them.

The condition where all available binding sites on a carrier protein are occupied by the transported substance, resulting in a plateau in the transport rate.

The process of releasing cellular contents, like hormones or enzymes, through fusion of a membrane-bound vesicle with the cell's outer membrane.

The difference in electrical charge across a cell's membrane, caused by an uneven distribution of ions.

The Na+/K+ pump moves three sodium ions (Na+) out of the cell for every two potassium ions (K+) it pumps in. This creates a negative charge inside the cell, contributing to the membrane potential.

K+ leak channels allow a small amount of potassium ions (K+) to leak out of the cell, further increasing the negative charge inside. This contributes to the resting membrane potential.

The stable, negative membrane potential of a cell when it's not actively signaling or transmitting impulses.

Sodium (Na+), potassium (K+), and large, negatively charged intracellular proteins are the main players in generating the resting membrane potential (RMP).

The Na+/K+ pump actively maintains the concentration gradients of sodium and potassium ions across the membrane, which is essential for the resting membrane potential.

The movement of substances across a cell membrane without requiring energy from the cell, driven by a concentration gradient or pressure difference.

The movement of substances across a cell membrane that requires energy from the cell, typically going against a concentration gradient.

A method of transporting substances across the cell membrane using membrane-bound sacs called vesicles. Examples include exocytosis and endocytosis.