1. Physiology

3. 4-Metbolism
Metabolism: is the set of chemical reactions that occur in living organisms to maintain life.
These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments.

4. Metabolism is usually divided into two categories:
Catabolism: breaks down organic matter, for example to produce energy in cellular respiration.
Anabolism:constructing components of cells such as proteins and nucleic acids.
Enzymes are important to metabolism because they act as catalysts to allow chemical reactions to proceed quickly and efficiently.

5. Metabolism Key Biomolecules In Metabolism:
Most of the structures that make up animals, plants and microbes are made from three basic types of molecule:
proteins,
carbohydrates
and lipids (often called fats).
As these molecules are important for life, metabolism focuses on utilizing these molecules in two ways:
in the construction of cells and tissues,
or breaking them down and using them as a source of energy.
These macromolecules are essential parts of all living organisms.

6. Metabolism Important biochemicals: 1- Proteins:
Proteins are made of amino acids arranged in a linear chain and joined together by peptide bonds.
Many proteins are the enzymes that catalyze the chemical reactions in metabolism.
Other proteins have structural or mechanical functions, such as the proteins that form the cytoskeleton.
Proteins are also important in cell signalling, immune responses, active transport across membranes.

7. Metabolism
2- Lipids
Lipids composed of three fatty acids and glycerol molecule.
They construct part of the cell membrane.
They are a source of energy.
Steroids such as cholesterol are another major class of lipids that are made in cells.

8. Metabolism 3- Carbohydrates
Carbohydrates are straight-chain aldehydes or ketones with many hydroxyl groups that can exist as straight chains or rings.
Carbohydrates are the most abundant biological molecules, and found as storage for producing energy (e.g. glycogen) and structural components (cellulose in plants, chitin in animals).
The basic carbohydrate units are called monosaccharides and include galactose, fructose, and glucose.
Monosaccharides can be linked together to form polysaccharides.

9. Metabolism 4- Coenzymes
Metabolism involves chemical reactions, most involve metabolic intermediates called coenzymes.
Coenzymes are therefore continuously being made, consumed and then recycled.
One central coenzyme is adenosine triphosphate (ATP), the energy source of cells. and used to transfer chemical energy between different chemical reactions.
ATP acts as a bridge between catabolism and anabolism, with catabolic reactions generating ATP and anabolic reactions consuming it.
It also serves as a carrier of phosphate groups in phosphorylation reactions.

10. Metabolism 5- Vitamines
Vitamin is an organic compound needed in small quantities that cannot be made in the cells.
In human nutrition, most vitamins function as coenzymes after modification.
Nicotinamide adenine dinucleotide (NADH), a derivative of vitamin B3 (niacin), is an important coenzyme that acts as a hydrogen acceptor.
NAD+ exists in two related forms in the cell, NADH and NADPH.
The NAD+/NADH form is more important in catabolic reactions, while NADP+/NADPH is used in anabolic reactions.

11. Metabolism 6- Minerals & Cofactors a) Elements
They are inorganic elements play important roles in metabolism; (e.g. sodium and potassium).
About 99% of mammals' mass are the elements carbon, nitrogen, calcium, sodium, chlorine, potassium, hydrogen, phosphorus, oxygen and sulfur.
The organic compounds (proteins, lipids and carbohydrates) contain the majority of the carbon and nitrogen and most of the oxygen and hydrogen is present as water.
b) Ions:
The most important inorganic ions are sodium, potassium, calcium, magnesium, chloride, phosphate, and the organic ion bicarbonate.
These Ions are also critical for nerves and muscles.

12. Catabolism & Anabolism

13. The Summary Metabolism
Is the break down of large molecules to provide energy and components needed for anabolic reactions.
Is the constructive processes that uses energy formed by catabolism to synthesize complex molecules for make up cellular structures.
Metabolism