The Chemical Basis of Life II: Organic Molecules

This set of flashcards covers key vocabulary and concepts from Chapter 3: The Chemical Basis of Life II: Organic Molecules, focusing on lipids, membranes, and transport mechanisms.

Lipids

Carbon-containing compounds that are largely nonpolar and hydrophobic.

Phospholipids

Molecules consisting of glycerol, two fatty acids, and a phosphate group, making them amphipathic.

Amphipathic

Molecules that have both hydrophilic (water-attracting) and hydrophobic (water-repelling) parts.

Dehydration Reaction

A chemical reaction where two molecules combine to form a larger molecule, producing water as a byproduct.

Saturated Fatty Acids

Fatty acids that have all carbons saturated with hydrogen, typically solid at room temperature.

Unsaturated Fatty Acids

Fatty acids that contain one or more double bonds, usually liquid at room temperature.

Ester Bond

The bond formed between glycerol and fatty acids during the formation of fats.

Fluid Mosaic Model

A model that describes the structure of cell membranes as a mosaic of various components that move freely.

Transmembrane Proteins

Proteins that span the entire lipid bilayer of membranes, embedded in the phospholipid bilayer.

Peripheral Membrane Proteins

Proteins found on the exterior or interior surfaces of membranes, not embedded within the lipid bilayer.

Active Transport

Movement of molecules across a membrane against their concentration gradient, requiring energy.

Simple Diffusion

The passive movement of molecules from an area of high concentration to an area of low concentration.

Facilitated Diffusion

The process of spontaneous passive transport of molecules or ions via a membrane protein.

Osmosis

The diffusion of water across a selectively permeable membrane.

Tonicity

The relative concentration of solutes in two fluids separated by a semipermeable membrane.

Isotonic Solution

A solution where the solute concentration is the same inside and outside the cell.

Hypertonic Solution

A solution with a higher solute concentration compared to the inside of a cell.

Hypotonic Solution

A solution with a lower solute concentration compared to the inside of a cell.

Gradient

A physical difference in concentration of a substance between two adjoining regions.

Transport Proteins

Transmembrane proteins that facilitate the movement of ions and hydrophilic molecules across membranes.

Channels

Protein structures that provide an open passageway for ions or molecules to cross the membrane.

Transporters

Also known as carriers, these proteins undergo conformational changes to move solutes across membranes.

Uniporter

A transporter that moves a single molecule or ion across the membrane.

Symporter

A transporter that moves two or more molecules in the same direction across a membrane.

Antiporter

A transporter that moves two or more molecules in opposite directions across a membrane.

Active Transport Pump

A mechanism, such as the Na+/K+ ATPase, that actively moves ions against their gradients.

Hydrophobic

Substances that do not interact well with water.

Hydrophilic

Substances that interact well with water.

Primary Active Transport

Directly uses energy to transport a solute against its concentration gradient.

Secondary Active Transport

Uses a pre-existing gradient established by primary active transport to drive the transport of other solutes.

Concentration Gradient

The difference in concentration of a substance between two areas.

Polymers

Large molecules made up of repeating units (monomers) connected by chemical bonds.

Monomers

Single units that can join together to form larger molecules.

Carbon Atoms

Atoms with atomic number 6 that can form four bonds, making them versatile in forming organic molecules.

Chemical Gradient

A difference in the concentration of a substance between two areas.

Fluidity of Membranes

The viscosity of lipid bilayers in membranes that affects their functions.

Hydrophobic Interior

The nonpolar core of the phospholipid bilayer that acts as a barrier to hydrophilic substances.

Gradient Effects on Transport

Membrane permeability is influenced by factors like size, polarity, charge, and concentration.

Lipid Bilayer Barrier

A structure of membranes that prevents the passage of hydrophilic molecules and ions.

Na+/K+ - ATPase

An active transport pump that maintains sodium and potassium gradients across the cell membrane.