Ch+4+FP module 3

Membrane structure

Phospholipid bilayer with embedded proteins forming a fluid-mosaic model.

Plasma membrane

The boundary that separates the cell from the outside environment.

Fluid-mosaic model

A model that describes the structure of the plasma membrane, depicting it as a flexible layer made of lipid molecules with embedded proteins.

Phospholipids

Molecules that make up the bilayer of cell membranes, having polar heads and non-polar tails.

Cholesterol in membranes

Steroid that regulates membrane fluidity.

Integral proteins

Proteins that are embedded within the phospholipid bilayer and may span the membrane.

Peripheral proteins

Proteins that are attached to the exterior or interior surfaces of the membrane.

Glycoproteins

Proteins that have carbohydrates attached to them, important for cell recognition.

Glycolipids

Lipids with carbohydrate groups attached, playing roles in cell recognition.

Membrane channels and carriers

Proteins that facilitate the passage of specific molecules through the membrane.

Selective permeability

The property of a membrane that allows certain substances to pass while blocking others.

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Osmosis

The diffusion of water across a selectively permeable membrane.

Isotonic solutions

Solutions with the same concentration of solutes as the cell, leading to no net water movement.

Hypotonic solutions

Solutions with lower solute concentration outside the cell, causing water to move into the cell.

Hypertonic solutions

Solutions with higher solute concentration outside the cell, leading to water loss from the cell.

Facilitated transport

Process that moves molecules across the plasma membrane from high to low concentration without using ATP.

Active transport

Movement of molecules against their concentration gradient, requiring energy in the form of ATP.

Sodium-potassium pump

An example of an active transport mechanism that moves sodium ions out and potassium ions into the cell.

Exocytosis

The process of exporting macromolecules from the cell using vesicles that fuse with the plasma membrane.

Endocytosis

Process by which cells internalize substances by engulfing them in vesicles.

Phagocytosis

A form of endocytosis known as 'cell eating', where large particles are engulfed.

Pinocytosis

A form of endocytosis known as 'cell drinking', where liquids or small particles are engulfed.

Receptor-mediated endocytosis

A specific form of endocytosis where target molecules bind to receptors before being enveloped in vesicles.

Metabolic reactions

Chemical reactions that occur within cells to maintain life.

Cell recognition

The ability of the cell to identify itself and distinguish from pathogens or other cells.

______ is the primary component of cell membranes.

Phospholipid.

The ______ model describes the arrangement of molecules within the plasma membrane.

Fluid-mosaic.

______ proteins span the entirety of the plasma membrane.

Integral.

______ refers to the ability of a membrane to allow some substances to pass while blocking others.

Selective permeability.

In ______ solutions, cells tend to swell as water moves into them.

Hypotonic.

The movement of water across a selectively permeable membrane is called ______.

Osmosis.

______ transport requires energy to move substances against their concentration gradient.

Active.

The process of engulfing large particles into the cell is known as ______.

Phagocytosis.

______ is the movement of molecules from an area of higher concentration to an area of lower concentration.

Diffusion.

The ______-potassium pump is a common example of active transport.

Sodium.