Lecture 1 Introduction to Biochemistry （生物化学） Zhihong Li（李志红） Department of Biochemistry
Introduction • What is the Biochemistry? • History and development • How to study Biochemistry?
1. Biochemistry • Definition:The chemistry of life • The science concerned with the chemical basis of life. • The science concerned with the various molecules that occur in living cells and organisms and with their chemical reaction. • Anything more than a superficial comprehension of life – in all its diverse manifestation - demands a knowledge of biochemistry.
Biochemistry • 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
Biochemistry • Medical students who acquire a sound knowledge of biochemistry will be in a strong position to deal with two central concerns of the health sciences: (1) the understanding and maintenance of health (2) the understanding and effective treatment of disease • Causes of cancers • Molecular lesions causing various genetic diseases • Rational design of new drugs
2. History and developmentof Biochemistry 1903, Neuberg (German):“Biochemistry” “Chemistry of Life”
Flow of information: from nucleic acids to proteins DNARNAProtein Two notable breakthroughs (1) Discovery of the role of enzymes as catalysts (2) Identification of nucleic acids as information molecules
Some historic events • In 1937， Krebsfor the discovery of theCitric Acid Cycle-won the Nobel Prize in Physiology or Medicine in 1953 • In 1953，Watson & Crickfor the discovery of the“DNA Double Helix” -won the Nobel Prize in Physiology orMedicine in 1962
In 1955，Sangerfor the determination ofinsulinsequence- won the Nobel Prize in Physiology or Medicine in 1956 • In 1980， Sanger & Gilbert forSequencing of DNA-won the Nobel Prize in Chemistry in 1980 • In 1993, Kary B. Mullis for invention of PCR method -won the Nobel Prize in Chemistry in 1993
Transgenic animal Gene engineering Green Fluorescence protein Clone
DNARNAProtein 3.What dose the Biochemistry discuss? • structure and function of cellular components • proteins, carbohydrates, lipids, nucleic acids and other biomolecules • Metabolism and Regulation • Gene expression and modulation
Polymers and Monomers • Each of these types of molecules are polymers that are assembled from single units called monomers. • Each type of macromolecule is an assemblage of a different type of monomer.
Macromolecule Carbohydrates Lipids Proteins Nucleic acids Monomer Monosaccharide Not always polymers; Hydrocarbon chains Amino acids Nucleotides
How do monomers form polymers? • In condensation reactions (also called dehydration synthesis), a molecule of water is removed from two monomers as they are connected together.
Building block Simple sugar Amino acid Nucleotide Fatty acid Macromolecule Polysaccharide Protein (peptide) RNA or DNA Lipid Anabolic Catabolic
4. Cells Basic building blocks of life Smallest living unit of an organism A cell may be an entire organism (unicellular) or it may be one of billions of cells that make up the organism (multicellular). Grow, reproduce, use energy, adapt, respond to their environment Many cannot be seen with the naked eye a typical cell size is 10µm; a typical cell mass is 1 nanogram.)
Cells May be Prokaryotic or Eukaryotic • Prokaryotes (Greek: pro-before; karyon-nucleus) include various bacteria • lack a nucleus or membrane-bound structures called organelles • Eukaryotes (Greek: eu-true; karyon-nucleus) include most other cells (plants, fungi, & animals) • have a nucleus and membrane-bound organelles
•Cell membrane & cell wall • •Nucleoid region contains the DNA • Contain ribosomes (no membrane) • • Cell Membrane • • Nucleus • Cytoplasm with organelles
Characteristic Bio-membranes and Organelles • Plasma Membrane-Cell’s defining boundaryProviding a barrier and containing transport and signaling systems. • Nucleus – Cell’s information centerDouble membrane surrounding the chromosomes and the nucleolus. The place where almost all DNA replication and RNA synthesis occur.The nucleolus is a site for synthesis of RNA making up the ribosome • Mitochondria- the power generators • Mitochondria (Greek: mitos-thread; chondros-granule):Surrounded by a double membrane with a series of folds called cristae. Functions in energy production through metabolism. Contains its own DNA.
Endoplasmic reticulum (ER) – The transport network for molecules • Rough endoplasmic reticulum (RER) Covered with ribosomes (causing the "rough" appearance) which are in the process of synthesizing proteinsfor secretion or localization in membranes. • RibosomesProtein and RNA complex responsible for protein synthesis • Smooth endoplasmic reticulum (SER)A site for synthesis and metabolism of lipids.
Golgi apparatus -process and package the macromolecules.A series of stacked membranes. Vesicles carry materials from the RER to the Golgi apparatus. Vesicles move between the stacks while the proteins are "processed" to a mature form. • Lysosomes-contain digestive enzymeA membrane bound organelle that is responsible for degrading proteins and membranes in the cell. • Cytoplasmenclosed by the plasma membrane, liquid portion called cytosol and it houses the membranous organelles.
5. Biomolecules Just like cells are building blocks of tissues, biomolecules are building blocks of cells. Animal and plant cells contain approximately 10,000 kinds of biomolecules. Water constitutes 50-95% of cells content by weight. Ions like Na+, K+ and Ca2+ may account for another 1%. Almost all other kinds of biomolecules are organic (C, H, N, O, P, S). Organic compounds are compounds composed primarily of a Carbon skeleton.
Carbon • Carbon is more abundant in living organisms than it is in the rest of the universe. • What makes Carbon Special? Why is Carbon so different from all the other elements on the periodic table? • The answer derives from the ability of Carbon atoms to bond together to form long chains and rings.
Carbon can form immensely diverse compounds, from simple to complex. DNA with tens of Billions of Carbon atoms Methane with 1 Carbon atom
Biomolecules are compounds of carbon with a variety of functional groups
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)
Similarities among all types of cells • All cells use nucleic acids (DNA) to store information • Except RNA viruses, but not true cells (incapable of autonomous replication) • All cells use nucleic acids (RNA) to access stored information • All cells use proteins as catalysts (enzymes) for chemical reactions • A few examples of RNA based enzymes, which may reflect primordial use of RNA • All cells use lipids for membrane components • Different types of lipids in different types of cells • All cells use carbohydrates for cell walls (if present), recognition, and energy generation
How much biochemistry do you need to know for this course? • Carbohydrates • Lipids • Proteins • Nucleic Acids 1. You are expected to learn the structure and functions of these organic compounds: 2. You will be expected to learn the basic biochemical processes of major cell functions, such as respiration, protein synthesis and so on.
6. Text book and references • U Satyanarayana, Biochemistry • Murray RK, Harper’s Illustrated Biochemistry, 26th ed. • Nelson DL and Cox MM.Lehninger Principles of Biochemistry, 5th ed. 2008.
7. Some tips for study of biochemistry • Inspiring interest, confidence • Previewing and reviewing freshly • Taking studying notes • Discussing ingroups • Practice, crosstalk with other subjects • Making use of internet
Just do as some proverbs say: “I hear, and I forget, I see, and I remember, I do, and I understand.” “Practice makes perfect” “No pains, no gains”
Final theory grade • Final theory grade= • First Assessment: 30~35% • Final exam: 45~50% • Daily performance: 20% • Notice: 1/3 absent, can not take part in the final exam.