Cell Membrane and Transport Quiz

The ability of substances to pass through the cell membrane.

The main component of the cell membrane, regulating what enters and exits.

These easily cross the lipid bilayer.

These molecules require proteins to pass through the membrane.

Protein channels that allow water to cross the membrane.

Higher temperatures increase membrane fluidity, allowing more substances to pass.

Cholesterol makes the membrane less permeable.

Temperature, cholesterol content, and molecule size influence how easily substances pass through the membrane.

The cell membrane is a selectively permeable, flexible layer surrounding the cell. It's a fluid mosaic model, meaning it's a double layer of phospholipids with proteins embedded.

The basic structure of the cell membrane. Two layers of phospholipid molecules, with hydrophilic heads facing outwards and hydrophobic tails inward.

Integral proteins are embedded within the lipid bilayer; peripheral proteins are on the surface of the membrane.

Membrane proteins perform various functions, including transport, enzymatic activity, cell communication (receptors), and cell adhesion.

Carbohydrates attached to proteins (glycoproteins) or lipids (glycolipids) on the outer surface of the cell membrane, forming the glycocalyx.

The glycocalyx gives the cell a negative charge, helps cells stick together, and is involved in cell recognition.

The cell membrane only allows certain substances to pass through it.

Cholesterol influences the fluidity and elasticity of the cell membrane.

Movement of molecules across a membrane without energy input, from high to low concentration.

Small, nonpolar molecules directly cross the cell membrane without transport proteins.

Molecules like glucose and ions move across the membrane with the help of transport proteins.

Difference in concentration of molecules across a membrane, driving diffusion.

How easily a substance dissolves in lipids (fats).

Proteins that assist the movement of specific molecules across the membrane.

Factors including concentration gradient, temperature, molecule size, membrane surface area, membrane thickness, and lipid solubility effects the speed of diffusion.

Movement of molecules against their concentration gradient using energy directly from ATP.

A primary active transport pump that moves 3 sodium ions out of the cell and 2 potassium ions in, using ATP.

Movement of molecules against their concentration gradient using the energy from an ion gradient created by primary active transport.

A secondary active transporter that uses the sodium concentration gradient to move glucose into the cell.

The process by which a cell takes in large molecules or liquids from the outside by folding its membrane inward.

A type of endocytosis where the cell engulfs large particles, like bacteria.

A type of endocytosis where the cell takes in liquids.

A specialized type of endocytosis where specific molecules bind to receptors on the cell surface, triggering their uptake into the cell.

Two types of proteins involved in receptor-mediated endocytosis. Klatrin helps form coated pits, while caveolae are small, flask-shaped structures.

The maximum rate at which transport proteins can move molecules across a membrane. It's reached when all carrier proteins are fully saturated with molecules.

A state where all available carrier proteins are bound to molecules, preventing further increase in transport rate, even if more molecules are present.

The concentration of a molecule needed to reach half of the Vmax. A low Km indicates high affinity, meaning the carrier protein binds easily to molecules. A high Km indicates low affinity.

The movement of water molecules across a semipermeable membrane from an area of low solute concentration to an area of high solute concentration.

A state where the concentration of water (or solute) is equal on both sides of a semipermeable membrane, resulting in no net movement of water.

Active transport has two main types: primary active transport, which directly uses ATP to move substances, and secondary active transport, which indirectly uses ATP by harnessing the electrochemical gradient of another substance.

A type of receptor-mediated endocytosis involving clathrin proteins, forming coated pits to internalize large specific molecules like cholesterol.

A type of receptor-mediated endocytosis involving caveolin proteins, forming small invaginations called caveolae to internalize small, lipid-soluble molecules.

Cells release various substances through exocytosis, including waste products, neurotransmitters, hormones, and proteins.

Both exocytosis and endocytosis involve the formation of membrane-bound vesicles. However, exocytosis releases substances outside the cell, while endocytosis takes substances inside.