Zhihong Li, PhD Department of Biochemistry Introduction to Biochemistry （生物化学）

Zhihong Li, PhDDepartment of Biochemistr

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Introduction to Biochemistry

（生物化学）

Biochemistry

• Definition: The chemistry of life– concerned with the chemical basis of life.– concerned with the various molecules that occur

in living cells and organisms and with their chemical reaction.

• Aim: to describe and explain, in molecular terms, all chemical processes of living cells– Structure-function– Metabolism and Regulation– How life began ？

Biochemistry

•Significance: be essential to all life sciences as the common knowledge – Genetics; Cell biology; Molecular

biology– Physiology and Immunology– Pharmacology and Pharmacy– Toxicology; Pathology; Microbiology– Zoology and Botany

Cells

• Basic building blocks of life.• Smallest living unit of an organism.• A cell may be an entire organism (unicellular

organism) or it may be one of billions of cells that make up the organism (multicellular organism).

• Grow, reproduce, use energy, adapt and respond to their environment.

Cells May be Prokaryotic or Eukaryotic

• Prokaryotes (Greek: pro-before; karyon-nucleus) – include various bacteria – lack a nucleus or membrane-bound str

uctures called organelles

• Eukaryotes (Greek: eu-true; karyon-nucleus) – include most other cells (plants, fungi,

& animals)– have a nucleus and membrane-bound

organelles

Characteristic Bio-membranes and Organelles

• Mitochondria- the power generatorsMitochondria (Greek: mitos-thread; chondros-granule): Surrounded by a double membrane with a series of folds called cristae. Functions in energy production through metabolism.

•Plasma Membrane-Cell’s defining boundary Providing a barrier and containing transport and signaling systems.

•Nucleus – Cell’s information center Double membrane surrounding the chromosomes and the nucleolus. The place where almost all DNA replication and RNA synthesis occur.

•Rough endoplasmic reticulum (RER) Covered with ribosomes (causing the "rough" appearance) which are in the process of synthesizing proteins for secretion or localization in membranes.

•Ribosomes: responsible for protein synthesis

•Smooth endoplasmic reticulum (SER)A site for synthesis and metabolism of lipids.

Endoplasmic reticulum (ER) – The transport network for molecules

•Cytoplasmenclosed by the plasma membrane, liquid portion called cytosol and it houses the membranous organelles.

•Lysosomes-contain digestive enzymeA membrane bound organelle that is responsible for degrading proteins and membranes in the cell.

•Golgi apparatus -process and package the macromolecules.A series of stacked membranes. Vesicles move between the stacks while the proteins are "processed" to a mature form.

Biomolecules

• Building blocks of cells. • Animal and plant cells contain approximately

10,000 kinds of biomolecules.– Water: constitutes 50-95% of cells contents by wei

ght.– Ions: like Na+, K+ and Ca2+ may account for another

1%.– Organic compounds: compounds composed primar

ily of a Carbon skeleton.

Types of biomolecules

• Small molecules: – Lipid, phospholipid, glycolipid, sterol – Vitamin – Hormone, neurotransmitter – Carbohydrate, sugar

• Monomers: – Amino acids – Nucleotides – Monosaccharides

• Polymers: – Peptides, oligopeptides, polypeptides, proteins – Nucleic acids, i.e. DNA, RNA – Oligosaccharides, polysaccharides (including cellulose)

Chemical composition of a normal man (weight 65 kg)

Constituent Percent (%) Weight (kg)

Water 61.6 40

Protein 17.0 11

Lipid 13.8 9

Carbohydrate

1.5 1

Minerals 6.1 4

Structural hierarchy in the molecular organization of cells

Topics Instructor

1Introduction , amino acid and protein

(6h) Zhihong Li

2 Nucleic acid (4h) Zhihong Li

3 Carbohydrates (2h) Zhihong Li

4 Vitamins (4h) Zhihong Li

5 Enzymes (6h) Zhihong Li

6 Metabolism of carbohydrates (8h) Yanlin Wang

7 Midterm assessment

8 Bioenergetics (4h) Zicheng Li

9 Metabolism of lipids (6h) Deqiao Sheng

10 Metabolism of amino acids (6h) Zicheng Li

11 Integration of metabolism and review(2h) Zicheng Li

• Satyanarayana U, Biochemistry.

• Murray RK, Harper’s Illustrated Biochemistry, 26th ed.

• Nelson DL and Cox MM. Lehninger Principles of Biochemistry, 5th ed.

Text book and references

• Inspiring interest, confidence

• Previewing and reviewing freshly

• Taking studying notes

• Discussing in groups

• Practice, crosstalk with other subjects

• Making use of internet

Some tips for study of Biochemistry

Final theory grade

• Final theory grade=– Daily performance: 15% – Midterm assessment: 30%– Final exam: 55%

• Notice: 1/3 absent, can not take part in the final exam.