Chapter 7 (EXAM 2)

Phospholipid

Amphipathic molecules, containing hydrophobic and hydrophilic regions

Polar

Molecules that have a charge separation

Amphipillic

Molecules that have both hydrophobic and hydrophilic parts.

Non-Polar

Lack a charge separation`, tend to not mix with water

transmembrane proteins

Proteins that span across the lipid bilayer of cell membranes, facilitating transport and communication.

Peripheral proteins

Proteins that are not embedded

Permeability

The ability of a membrane to allow substances to pass through it, which can vary based on the membrane's composition and structure.

Endocytosis

Cell takes macromolecules by forming vesicles from the plasma membrane

Exocytosis

Transport vesicles migrate to the membrane, fuse, and release their contents

Fluid Mosaic Model

Membrane is a fluid structure with various proteins embedded into it

Cholesterol

A lipid that helps stabilize membrane fluidity at varying temperatures, contributing to the overall structure and function of the plasma membrane.

Osmosis

Movement of water

Diffusion

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

Glycolipids

Lipids with attached carbohydrate groups that contribute to cell membrane structure and signaling.

Glycoproteins

Proteins with attached carbohydrate groups that play key roles in cell recognition and signaling.

Equilibrium

Movement is same in both directions

Hypertonic Solutions

Solute concentration is greater than that inside of cell; cell loses water

Hypotonic

Solutions where solute concentration is lower than that inside of the cell; causes cell swelling.

Cotransport

Occurs when active transport of a solute indirectly drives transport of another solute

Pinocytosis

Cell creates vesicle around fluid

Phagocytosis

cell engulfs particle in a vacuole.

Functions of Proteins

Transport

Attachment to the cytoskeleton

Enzymatic activity

Cell signaling and communication

Structural support

How is Cell membrane constructed

Lipid bilayer embedded with proteins constructs the membrane. Bilayer is amphiphilic. Proteins interspersed within bilyaer.

Transport Protein

Facilitates the movement of molecules across cell membranes.

Channel Proteins

Facilitates the passage of water

Carrier Proteins

Binds to molecules and change shape to shuttle them across the membrane

Compare and contrast active vs passive transport

Feature	Passive Transport	Active Transport
Energy Requirement	No energy required	Requires energy (ATP)
Movement	Down concentration gradient	Against the concentration gradient
Examples	Diffusion, osmosis, facilitated diffusion	Sodium-potassium pump, exocytosis, endocytosis1

Facilitated Diffusion

Passive transport aided by proteins

Sodium Potassium Pump

A type of active transport that moves sodium ions out of the cell and potassium ions into the cell against their concentration gradients, using ATP.

Electrochemical Gradient

The difference in concentration and electric charge across a membrane that affects the movement of ions.

Desmosomes

Fastens cells together into small sheets