A-Level Biology
Complete Revision Pack
Detailed Notes with Diagrams, Examples & Exam Practice
,Table of Contents
1. Biological Molecules
2. Cells
3. Exchange & Transport
4. Genetics
5. Energy & Ecosystems
6. Organisms Respond to Their Environment
7. Evolution & Biodiversity
8. Practical Skills & Data Analysis
9. Cell Division & Cell Cycle
10. Enzymes
11. Immunity
12. Gene Technology
13. Populations & Ecosystems
, A-Level Biology Complete Pack
Section 1: Biological Molecules
Biological molecules are essential for all living organisms. They include carbohydrates,
lipids, proteins, and nucleic acids. These molecules provide energy, structure, genetic
information, and perform vital roles in metabolism. Understanding their structure and
function is key to mastering A-Level Biology.
Carbohydrates
Carbohydrates are composed of carbon (C), hydrogen (H), and oxygen (O). They are a
primary source of energy. The basic unit is the monosaccharide (e.g., glucose, galactose,
fructose). Two monosaccharides form a disaccharide (e.g., sucrose, maltose, lactose)
through a condensation reaction. Many monosaccharides link to form polysaccharides
(e.g., starch, glycogen, cellulose).
Type Examples Function
Monosaccharides Glucose, Fructose Quick energy source
Disaccharides Sucrose, Lactose Transportable energy form
Polysaccharides Starch, Glycogen, Cellulose Energy storage, structural support
Worked Example: Condensation Reaction of Glucose
Two glucose molecules join together through a condensation reaction, forming maltose
and releasing a molecule of water. This bond is called a glycosidic bond.
Proteins
Proteins are made of amino acids linked by peptide bonds. They are vital for structure
(collagen), transport (hemoglobin), enzymes (catalysts), and hormones (insulin). Protein
structure has four levels: primary, secondary, tertiary, and quaternary.
Complete Revision Pack
Detailed Notes with Diagrams, Examples & Exam Practice
,Table of Contents
1. Biological Molecules
2. Cells
3. Exchange & Transport
4. Genetics
5. Energy & Ecosystems
6. Organisms Respond to Their Environment
7. Evolution & Biodiversity
8. Practical Skills & Data Analysis
9. Cell Division & Cell Cycle
10. Enzymes
11. Immunity
12. Gene Technology
13. Populations & Ecosystems
, A-Level Biology Complete Pack
Section 1: Biological Molecules
Biological molecules are essential for all living organisms. They include carbohydrates,
lipids, proteins, and nucleic acids. These molecules provide energy, structure, genetic
information, and perform vital roles in metabolism. Understanding their structure and
function is key to mastering A-Level Biology.
Carbohydrates
Carbohydrates are composed of carbon (C), hydrogen (H), and oxygen (O). They are a
primary source of energy. The basic unit is the monosaccharide (e.g., glucose, galactose,
fructose). Two monosaccharides form a disaccharide (e.g., sucrose, maltose, lactose)
through a condensation reaction. Many monosaccharides link to form polysaccharides
(e.g., starch, glycogen, cellulose).
Type Examples Function
Monosaccharides Glucose, Fructose Quick energy source
Disaccharides Sucrose, Lactose Transportable energy form
Polysaccharides Starch, Glycogen, Cellulose Energy storage, structural support
Worked Example: Condensation Reaction of Glucose
Two glucose molecules join together through a condensation reaction, forming maltose
and releasing a molecule of water. This bond is called a glycosidic bond.
Proteins
Proteins are made of amino acids linked by peptide bonds. They are vital for structure
(collagen), transport (hemoglobin), enzymes (catalysts), and hormones (insulin). Protein
structure has four levels: primary, secondary, tertiary, and quaternary.
