Biochemistry: Proteins and Lipids
Proteins and lipids are essential biomolecules. Proteins are made of amino acids and perform structural, enzymatic, and regulatory functions. Lipids store energy, form cell membranes, and act as chemical messengers.
What You Need to Know
Key Concept Diagram
Proteins are polymers of amino acids linked by peptide bonds; sequence determines shape and function
Enzymes are biological catalysts that speed up reactions without being consumed
Lipids include fats (triglycerides), phospholipids (cell membranes), and steroids (hormones)
Cell membranes are phospholipid bilayers: hydrophilic heads face water, hydrophobic tails face inward
Key Vocabulary
Protein
A large biomolecule made of amino acid chains; performs structural, enzymatic, and regulatory roles
Enzyme
A protein that acts as a biological catalyst to speed up biochemical reactions
Lipid
A group of biomolecules including fats, oils, and steroids; largely hydrophobic
Phospholipid bilayer
The double layer of phospholipids that forms the structure of cell membranes
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
What are the building blocks (monomers) of proteins?
Question 2
An enzyme is best described as:
Question 3
The cell membrane is made of a phospholipid bilayer. What faces the water outside and inside the cell?
Key Concepts Summary
- ●Proteins are polymers of amino acids linked by peptide bonds; sequence determines shape and function
- ●Enzymes are biological catalysts that speed up reactions without being consumed
- ●Lipids include fats (triglycerides), phospholipids (cell membranes), and steroids (hormones)
- ●Cell membranes are phospholipid bilayers: hydrophilic heads face water, hydrophobic tails face inward