The document introduces metabolism as the sum of all chemical reactions within an organism that allows it to grow and maintain itself, and describes the two main types as catabolism which breaks down complex molecules to release energy and anabolism which uses that released energy to synthesize complex molecules from simpler precursors. Metabolic pathways involve a series of enzyme-catalyzed reactions that transform a starting molecule into a product, and metabolism occurs through stages of breaking down molecules, activating precursors, and assembling complex structures.

1. INTRODUCTION TO
METABOLISM
Dr. Ifat Ara Begum
Assistant Professor
Dept. of Biochemistry
Dhaka Medical College
Dhaka

2. INTRODUCTION
Metabolism is the sum of an
organism’s chemical reaction
It is an emergent property of life
that arises from interactions
between molecules within the cell

3. TYPES OF METABOLISM
Catabolism: Breaking down of
complex molecules into simpler
compounds releasing energy.
Anabolism: Synthesis of complex
molecules from simpler ones by
consuming energy.

4. A) CATABOLISM
The set of metabolic processes
that break down large molecules
The purpose of the catabolic
reactions is to provide the energy
and components needed by
anabolic reactions.

5. B) ANABOLISM
The set of constructive metabolic
processes where the energy
released by catabolism is used to
synthesize complex molecules
Anabolism involves three basic
stages:

6. CONTD
i. The production of precursors (like
amino acids, monosaccharides,
nucleotides)
ii. Their activation into reactive
forms using energy from ATP
iii. The assembly of these precursors
into complex molecules such
as proteins, polysaccharides, lipid
s and nucleic acids.

8. METABOLIC PATHWAYS
A metabolic pathway begins with a
specific molecule and ends with a
product.
Each step is catalyzed by a specific
enzyme

9. STAGES OF METABOLISM

10. STAGES OF METABOLISM