Highlight: Lipids contain more energy per gram than carbohydrates and proteins, making them efficient energy storage molecules.

Definition: Fats are lipids that are solid at room temperature, while oils are liquid at room temperature.

Example: Glycerol (C₃H₈O₃) combines with fatty acids to form more complex lipids.

Definition: Phospholipids are modified triglycerides where one fatty acid chain is replaced with a phosphate group.

Highlight: Phospholipids have both hydrophilic (water-loving) heads and hydrophobic (water-fearing) tails, crucial for cell membrane formation.

Example: When mixed with water, phospholipids can form structures called micelles, with heads facing water and tails clustering together.

Definition: A phospholipid bilayer is a double layer of phospholipids that forms the foundation of cell membranes.

Highlight: Lipids serve multiple crucial functions including protection of organs, thermal insulation, energy storage, and hormone production.

Example: Liposomes are spherical structures formed by phospholipid bilayers that trap water in their center.

Definition: Primary structure refers to the sequence of amino acids in a polypeptide chain.

Vocabulary: Alpha helix - A spiral structure held together by hydrogen bonds. Beta strand - An almost straight chain structure that can form pleated sheets.

Highlight: The tertiary structure creates unique active sites in enzymes through various types of bonds between R groups.

Example: Hemoglobin, with its four polypeptide chains, exemplifies quaternary structure.

Definition: Globular proteins are water-soluble and include antibodies and hemoglobin, while fibrous proteins form tough, insoluble structures found in connective tissue.

Highlight: The final 3D structure of proteins can be either globular or fibrous, each with distinct properties and functions.

Definition: Denaturation is the process where a protein's structure changes when the bonds maintaining its shape are broken.

Example: Hair perming involves breaking disulfide bonds to reshape protein structure.

Highlight: Different factors can cause denaturation, including high temperatures, extreme pH, and reducing agents.

Definition: A polypeptide is a single chain of amino acids formed through condensation reactions, with one end containing a free amino group and the other a free carboxyl group.

Example: Glycine and alanine are examples of amino acids that can join to form dipeptides and eventually polypeptides.

Vocabulary: Condensation reaction - A chemical reaction where two molecules combine to form a larger molecule, releasing water as a byproduct.