Bio111 Exam 2- Module 5- TAMU- Fletcher

Fluid Mosaic Model

Describes the cell membrane as a fluid layer made of phospholipids with a mosaic of proteins, cholesterol, and carbohydrates.

Phospholipids

Form the bilayer of the cell membrane with hydrophilic heads facing outward and hydrophobic tails facing inward.

Cholesterol

Scattered within the phospholipid bilayer; stabilizes membrane and affects fluidity.

Integral proteins

Proteins that span the membrane, involved in transport and signaling.

Peripheral proteins

Proteins located on the surface of the membrane, providing support and communication.

Asymmetry in membranes

Inner and outer layers of the membrane differ in composition and function.

Glycolipids

Lipids with carbohydrate chains that are mainly on the outer layer of the cell membrane.

Diffusion

Movement of molecules from high concentration to low concentration.

Osmosis

Diffusion of water through a selectively permeable membrane.

Amphipathic

Molecules with both hydrophobic and hydrophilic parts, such as phospholipids.

Electrogenic

Describes a process that generates an electrical charge difference, like ion pumps.

Hypotonic solution

A solution where water enters the cell, causing it to swell or burst.

Isotonic solution

A solution where water moves equally, and the cell stays the same size.

Hypertonic solution

A solution where water leaves the cell, causing it to shrink.

Simple diffusion

Transport method where molecules pass directly through the lipid bilayer without proteins or energy.

Facilitated diffusion

Transport method that uses proteins to move molecules down their concentration gradient.

Passive transport

Movement of substances without energy, moving down the concentration gradient.

Active transport

Movement of substances that requires energy (ATP) to go against the concentration gradient.

Sodium-Potassium Pump

A pump that moves 3 Na⁺ out and 2 K⁺ into the cell using ATP.

Electrochemical gradient

A combination of ion concentration difference and electrical charge across the membrane.

Co-Transport

Also known as secondary active transport, it uses energy from one gradient to move another molecule against its gradient.

Phagocytosis

Type of endocytosis known as 'cell eating,' where solids or large particles are engulfed.

Pinocytosis

Type of endocytosis known as 'cell drinking,' where fluids and dissolved substances are taken in.

Receptor-Mediated Endocytosis

Endocytosis where specific molecules bind to receptors and are internalized.

Endocytosis

Process of importing material into the cell using vesicles.

Exocytosis

Process of exporting material out of the cell using vesicles.

Transport proteins

Proteins that assist in moving molecules across the cell membrane.

Selectively permeable membrane

A membrane that allows certain molecules to pass while blocking others.

Kinks in unsaturated fats

Structural feature that prevents tight packing, leading to increased membrane fluidity.

Temperature effect on membrane fluidity

Higher temperatures increase fluidity, while lower temperatures decrease it.

Energy requirement for active transport

Active transport requires ATP and specific membrane proteins.

Carrier proteins

Proteins that facilitate the active transport of molecules across the membrane.

Vesicles

Membrane-bound sacs used in bulk transport to move large molecules.

Membrane stabilization

Cholesterol in the membrane contributes to the stability and fluidity of the membrane.

Gradient movement

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

Role of glycolipids

Important for maintaining cell-cell interactions and communication.

Ion gradients

Differences in ion concentrations across a membrane that are crucial for cell functions.