Cell Biology Chapter - Membrane Functions Quiz

The cell membrane acts as a barrier, allowing the cell to maintain its internal environment and interact with the surrounding environment.

Phospholipids form a double layer, creating a barrier against water-soluble substances. Cholesterol adds stability and fluidity to the membrane.

Transmembrane proteins span the entire membrane while others reside only on one side. They play various roles, including transport, signaling, and cell adhesion.

Carbohydrates attached to lipids or proteins form the glycocalyx, serving as identification markers for cell recognition and interaction.

This model describes the cell membrane as a fluid, dynamic structure with embedded proteins that carry out various functions.

Desmosomes: anchoring junctions for strong cell-to-cell attachments. Tight junctions: seals prevent leakage between cells. Gap junctions: channels allowing communication between cells.

The extracellular matrix is a gel-like substance surrounding cells, containing fibrous proteins like collagen, elastin, and fibronectin. It provides structural support, regulates cell function, and facilitates diffusion.

The ECM serves as a pathway for diffusion of substances, controls cell behavior, and can specialize for specific functions, like cartilage or bone.

Specialized cell junctions that act like "spot rivets", holding cells together through plaque, glycoprotein filaments, and keratin filaments. Found in tissues like skin, heart, and uterus.

Tight junctions create a seal between cells, preventing the passage of substances between them. They are formed by junctional proteins at "kiss sites" and are essential for maintaining separate compartments with different chemical compositions. Found in epithelial tissues lining the intestines and kidneys.

Gap junctions form channels between cells, allowing small particles to pass through. These channels are formed by connexons, which are made of six subunits forming a tube-like structure. Found in electrically active tissues like cardiac and smooth muscle, enabling synchronized action and communication.

The movement of molecules across a cell membrane.

The passive movement of molecules from a region of higher concentration to a region of lower concentration. Requires no energy expenditure by the cell.

The passive movement of water molecules across a semi-permeable membrane from a region of higher water concentration to a region of lower water concentration. Requires no energy expenditure by the cell.

The net movement of molecules across a membrane following the concentration gradient. Requires no energy expenditure by the cell.

The movement of molecules across a membrane using a carrier protein. Requires no energy expenditure by the cell but is dependent on the availability of carrier proteins.

The movement of molecules against their concentration or electrochemical gradient, requiring energy (ATP) expenditure by the cell.

A type of active transport that directly uses energy from ATP hydrolysis to move molecules against their concentration gradient.

A type of active transport that uses the energy stored in the electrochemical gradient of one molecule to transport another molecule against its concentration gradient. Indirectly uses energy from ATP hydrolysis.

The process by which cells engulf substances from outside the cell by forming vesicles that pinch off from the plasma membrane.

The process by which cells release substances from inside the cell into the extracellular space by fusing vesicles with the plasma membrane.

Small, flask-shaped invaginations of the plasma membrane involved in various cellular processes, including membrane transport and signal transduction.

The tendency of a substance to move from an area where it is more concentrated to an area where it is less concentrated.

The difference in electrical potential across a membrane. It drives the movement of charged molecules across the membrane.