Fatty Acids: Saturated vs Unsaturated

Lipids are a diverse group of organic compounds that are soluble in organic solvents but not in water. They serve as energy sources and are stored for later use by animals.

Saponifiable lipids contain a carboxylic group, such as fatty acids and their esters. Non-saponifiable lipids lack a carboxylic group and include alcohols, alkanes, and terpenes.

Fatty acids are aliphatic monocarboxylic acids with a varying number of carbon atoms, usually in even numbers. Saturated fatty acids lack double bonds, while unsaturated ones have at least one double bond.

Saturated fatty acids have no double bonds in their aliphatic chains. Unsaturated fatty acids have at least one double bond in their chain.

The position of double bonds in unsaturated fatty acids can vary. In humans, they typically have a "cis" conformation, with R groups on the same side of the double bond.

Cis double bonds induce a bend in the molecular structure of fatty acids due to the R groups being on the same side of the double bond.

Natural fatty acids can be either saturated or unsaturated. Saturated fatty acids are typically solid at room temperature, while unsaturated fatty acids are typically liquid.

Different fatty acids have different melting temperatures. Unsaturated fatty acids with cis double bonds have lower melting points than saturated fatty acids.

Molecules that have both a hydrophilic (water-loving) and a hydrophobic (water-fearing) region. Think of them as having a "head" and a "tail."

The spontaneous process where amphipathic molecules self-organize into structures like micelles or bilayers in water. This happens because it reduces the contact between water and the hydrophobic parts.

A spherical structure formed by amphipathic molecules in water. The hydrophobic tails cluster inside, while the hydrophilic heads face the water.

A thin, double-layered structure formed by amphipathic molecules. The hydrophobic tails point inwards, while the hydrophilic heads face the water.

The property of a molecule to be attracted to water. These molecules tend to dissolve in water.

The property of a molecule to repel water. These molecules do not dissolve in water.

Biological membranes act as protective barriers between the cell and its environment, create compartments within cells, and control the movement of substances into and out of the cell.

Membranes are mainly composed of phospholipids. They have a thickness of about 5 nanometers, which is about 50 times thinner than a human hair.

A model of the cell membrane that describes it as a fluid, dynamic structure composed of a phospholipid bilayer with embedded proteins. The phospholipids can move laterally, creating a fluid mosaic.

Proteins that are partially embedded in the lipid bilayer of the cell membrane, interacting with its surface but not fully crossing it.

Proteins that are fully embedded in the lipid bilayer of the cell membrane, crossing it completely and often acting as channels or transporters.

Specialized protein channels that allow water molecules to pass through the cell membrane.

The process by which molecules or ions move across a cell membrane without requiring energy input.

The process by which molecules or ions move across a cell membrane against their concentration gradient, requiring energy input.

The difference in concentration of a substance across a membrane.

The ability of the cell membrane to allow the passage of some substances while preventing the passage of others.

A type of active transport where energy is directly obtained from ATP hydrolysis.

A type of active transport where energy is obtained indirectly from the concentration gradient of another substance.

A type of secondary active transport where two substances move in opposite directions across the membrane.

A type of secondary active transport where two substances move in the same direction across the membrane.

The process by which large particles are taken into a cell.

A type of endocytosis where the cell takes in solid particles.

A type of endocytosis where the cell takes in liquid droplets.

The process by which a cell releases substances from its interior.

A type of passive transport where molecules move across the cell membrane with the help of membrane proteins, from a region of high concentration to a region of low concentration.

A type of membrane protein involved in facilitated diffusion. It creates a channel through the membrane, allowing specific molecules to pass through.

A type of membrane protein involved in facilitated diffusion. This protein changes its shape to bind and transport specific molecules across the membrane.

In facilitated diffusion, the rate of transport increases as the concentration gradient increases, but eventually reaches a maximum (saturation).

The rate of transport in facilitated diffusion is limited by the number of available carrier proteins.

The concentration of a molecule at which the transport rate is half of the maximum (Vmax).

A substance that binds to the active site of a protein and inhibits its function.

The percentage of each lipid type in erythrocyte, myelin, and mitochondria membranes. For example, phosphatidyl choline accounts for 19% of the lipids in erythrocyte membranes.

Detergents disrupt the membrane structure by interacting with both hydrophobic and hydrophilic parts of lipids, effectively dissolving the membrane.

Toxins create pores in the membrane.

Cholesterol is an essential component of animal cell membranes, contributing to both structural integrity and fluidity. It adds stability and helps cells change shape.

Cholesterol can decrease the membrane permeability to water by stiffening the phospholipid bilayer.

Cholesterol is a lipid molecule with numerous functions within the cell membrane.

Phosphatidylcholine, phosphatidylethanolamine, cholesterol, glycolipids, and phosphatidylinositol are five major lipid types found in cell membranes.

The cell membrane is a dynamic structure that is constantly changing based on the needs of the cell.