Metabolism describes chemical reactions that maintain living cells and organisms. There are two main types of metabolic reactions: catabolism breaks down molecules, releasing energy, while anabolism uses this energy to build complex molecules. Enzymes catalyze metabolic reactions and allow organisms to couple spontaneous reactions that release energy to drive other reactions. The main biomolecules that make up living things - amino acids, lipids, carbohydrates, and nucleotides - are broken down and synthesized through metabolic pathways.

2. What is
METABOLISM?

3. Metabolism is a term that is used to
describe all chemical reactions involved
in maintaining the living state of the
cells and the organism.

4. The three main purposes of metabolism:
• The conversion of food energy to run cellular
processes
• The conversion of food/fuel to building
blocks for protein, lipids, nucleic acids and
some carbohydrates.
• The elimination of nitrogenous wastes.

5. Two types of
metabolic reactions:

6. Catabolism (breaking down)
•Catabolism is the set of metabolic
processes that break down large
molecules. These includes breaking
down and oxidizing food molecules.

7. The catabolic reactions in animal can be
separated into three main stages:
• First stage, large organic molecules, such as proteins,
polysaccharides, or lipids are digested into smaller
components outside cells.
• Second stage, Smaller molecules are taken up by cells and
converted to smaller molecules, usually acetyl coenzyme A
(acetyl-CoA) which releases some energy.
• Final stage, the acetyl group on the CoA is oxidized to water
and carbon dioxide in the citric acid cycle and electron
transport chain.

8. Catabolic reactions give out energy. They
are exergonic. In a catabolic reaction
large molecules are broken down into
smaller ones.

9. Examples of Catabolism:
• Carbohydrate Catabolism-glucose is released from
carbohydrates by special enzymes.
• Lipid Catabolism-fats, which are large lipid molecules are
degraded by the metabolism to produce energy and to
create other molecules.
• Protein Catabolism-enzyme known as proteinases break
bond between the amino acids in each protein,

10. Anabolism (building up)
•Anabolism is the set of constructive
metabolic processes where the energy
released by catabolism is used to
synthesize complex molecules.

11. Anabolism involves three basic stages:
• First, the production of precursor such as amino acids,
monosaccharides, isoprenoids and nucleotides.
• Second, their activation into reactive forms using energy
from ATP.
• Third, the assembly of these precursors into complex
molecules such as proteins, polysaccharides, lipids, and
nucleic acids.

12. Anabolic reactions use up energy. They
are endergonic. In an anabolic reaction
small molecules join to make larger ones.

13. Examples of Anabolism:
• Protein synthesis- proteins are synthesized from smaller
molecules called amino acids in a cell’s ribosomes.
• DNA synthesis- takes place in a cell’s nucleus just before the
cell divides.
• Growth of bones and muscles
• Anabolic steroid-increase protein within muscles cells, which
causes an increase in muscle mass.

15. How chemical reactions
occur during metabolism?

16. Chemical reactions that occur during
metabolism are affected by temperature.
Many animals maintain a constant a
constant temperature which results in
relatively stable rates of metabolic
reactions.

17. The chemical reactions of metabolism are
organized into metabolic pathways, in
which one chemical is transformed through
a series of steps into another chemical,
each step being facilitated by a specific
enzymes.

18. Classification of organism based on their metabolism
Energy
Source
Sunlight Photo
troph
Preformed
molecules
Chemo
Electron
Donor
Organic
compound
Organo
Inorganic
compound
Litho
Carbon
Source
Organic
compound
Hetero
Inorganic
compound
Auto

19. For metabolism to undergo, energy are
required:
• Energy can exist in two states:
• Kinetic energy-energy in motion
• Potential energy-stored energy

20. Free energy
•Free energy is available for doing work.
• Most chemical reactions release free energy---
they are exergonic (downhill)
• Some reactions require the input of free energy---
they are endergonic (uphill)

21. Thermodynamics of
Living Organisms

22. Living organism must obey the laws of
thermodynamics, which describe the
transfer of heat and work.

23. Law of Thermodynamics
• Energy cannot be created or destroyed- only
transformed.
• A closed system moves toward entropy,
increasing disorder.

24. What is ENZYME?

25. Enzyme are crucial to metabolism because
they allow organisms to drive desirable
reactions that require energy that will not occur
by themselves, by coupling them to
spontaneous reactions that release energy.

26. Enzymes may be pure proteins or proteins plus
cofactors such as metallic ions or coenzymes,
organic group that contain groups derived from
vitamins.

27. Function of enzyme:
• Enzyme act as catalyst---they allow a reaction to
proceed rapidly.
• They also allow the regulation of the rate of a
metabolic reaction.
• An enzyme works by binding with its substrate,
the molecule whose reaction is catalyzed.

28. BIOCHEMICALS

29. Most of the structures that make up animals,
plants and microbes are made from three basic
classes of molecules:
amino acids, carbohydrates, and lipids (often
called fat)

30. Type of Biochemicals
• Amino acids and proteins
• Lipids
• Carbohydrates
• Nucleotides
• Coenzymes
• Minerals and cofactors

31. AMINO ACIDS AND PROTEINS
• Proteins are made of amino acids arranged in a
linear chain joined together by peptides. Many
proteins are enzymes that catalyze the chemical
reaction of metabolism.

32. LIPIDS
• Are the most diverse group of biochemicals. Their
main structural uses are as part of biological
membranes both internal and external such as the
cell membrane, or as a source of energy.

33. CARBOHYDRATES
• Carbohydrates are aldehydes or ketones, with
hydroxyl groups attached, that can exist as
straight chains or rings. It is the most abundant
molecules, and fill numerous role such as storage
and transport of energy and structural
components.

34. NUCLEOTIDES
• Nucleotides act as coenzymes in metabolic-group-
transfer reaction. The two nucleic acid, DNA and
RNA, are polymers of nucleotides. Each
nucleotides is composed of a phosphate attached
to a ribose or deoxyribose sugar group.

35. COENZYMES
• Coenzymes are mostly derived from vitamins and
other organic essential nutrients in small amounts.
It consist of two groups: prosthetic group and
cosubstrates.

36. MINERALS AND COFACTORS
• Inorganic elements that play roles in metabolisms,
some are abundant while others functions at a
minute concentrations.