1. Introduction to Biochemistry
And Mol & Biol
Prof. Shaoping Ji
Department of Biochemistry and Molecular Biology
Medical School
Henan University

2. What is Biochemistry ?
Biochemistry is the application of chemistry to the study of biological processes at the cellular and molecular level.
It emerged as a distinct discipline around the beginning of the 20th century when scientists combined chemistry, physiology and biology to investigate the chemistry of living systems by:
Studying the structure and behavior of the complex molecules found in biological material and
the ways these molecules interact to form cells, tissues and whole organism
Biochemistry has become the foundation for understanding all biological processes. It has provided explanations for the causes of many diseases in humans, animals and plants."

3. Principles of Biochemistry
Cells (basic structural units of living organisms) are highly organized and constant source of energy is required to maintain the ordered state.
Living processes contain thousands of chemical pathways. Precise regulation and integration of these pathways are required to maintain life
Certain important pathways e.g. Glycolysis is found in almost all organisms. common pathway
All organisms use the same type of molecules: carbohydrates, proteins, lipids & nucleic acids.
Instructions for growth, reproduction and developments for each organism are encoded in their DNA

4. Cells Basic building blocks of life
Smallest living unit of an organism
Grow, reproduce, use energy, adapt, respond to their environment change
Many cannot be seen with the naked eye
A cell may be an entire organism or it may be one of billions of cells that make up the organism
Basis Types of Cells

5. Nucleoid region contains the DNA
•Cell membrane & cell wall
• Contain ribosomes (no membrane)
to make proteins in
their cytoplasm
Contain 3 basic cell structures:
• Nucleus
• Cell Membrane
• Cytoplasm with organelles

6. Two Main Types of Eukaryotic Cells

7. Biolog. Nanostructures
Biochemistry

8. How did organic complex molecules evolved from simple atoms?

10. How did organic complex molecules evolved from more simple molecules?
Biochemical Evolution
O2 ,CH4, H2O, NH3, HCN ?

11. How did organic complex molecules evolved from more simple molecules?
Urea was synthesized by heating the inorganic compound ammonium cyanate (1828)
This showed that compounds found exclusively in living organisms could be synthesized from common inorganic substances

12. The Urey-Miller experiment (1950)
Some amino acids could be produced:

13. Many Important Biomolecules are Polymers
Biopolymers - macromolecules created by joining many smaller organic molecules (monomers)
Condensation reactions join monomers (H2O is removed in the process)
Residue - each monomer in a chain

15. Molecular Organization of a cell

16. Water Water is used in most reactions in the body
About percent of an organism is water
Water is used in most reactions in the body
Water is called the universal solvent

17. Bio-molecules
Just like cells are building blocks of tissues likewise molecules are building blocks of cells.
Animal and plant cells contain approximately 10, 000 kinds of molecules (bio-molecules)
Water constitutes 50-95% of cells content by weight.
Ions like Na+, K+ and Ca+ may account for another 1%
Almost all other kinds of bio-molecules are organic (C, H, N, O, P, S)
Infinite variety of molecules contain C.
Most bio-molecules considered to be derived from hydrocarbons.
The chemical properties of organic bio-molecules are determined by their functional groups. Most bio-molecules have more than one.

18. Biomolecules – Structure
Anabolic
Building block
Simple sugar
Amino acid
Nucleotide
Fatty acid
Macromolecule
Polysaccharide
Protein (peptide)
RNA or DNA
Lipid
Catabolic

19. This process joins two sugar monomers to make a double sugar
Linking Monomers
Cells link monomers by a process called dehydration synthesis (removing a molecule of water)
Remove H
H2O Forms
Remove OH
This process joins two sugar monomers to make a double sugar

20. Breaking Down Polymers
Cells break down macromolecules by a process called hydrolysis (adding a molecule of water)
Water added to split a double sugar

21. Sugars Carbohydrates most abundant organic molecule found in nature.
Initially synthesized in plants from a complex series
of reactions involving photosynthesis.
Basic unit is monosaccharides.
Monosaccharides can form larger molecules e.g. glycogen, plant starch or cellulose.
Functions
Store energy in the form of starch (photosynthesis in plants) or glycogen (in animals and humans).
Provide energy through metabolism pathways and cycles.
Supply carbon for synthesis of other compounds.
Form structural components in cells and tissues.
Intercellular communications

22. Monosaccharides -Polysaccharides
Glucose - Cellulose
Glycosidic bonds connecting glucose residues are in red

23. Fatty acids - Lipids
Are monocarboxylic acid contains even number C atoms
Two types: saturated (C-C sb) and unsaturated (C=C db)
Fatty acids are components of several lipid molecules.
E,g. of lipids are triacylglycerol, steroids (cholesterol, sex hormones), fat soluble vitamins.
Functions
Storage of energy in the form of fat
Membrane structures
Insulation (thermal blanket)
Synthesis of hormones

24. Triglyceride
Fatty Acid Chains
Glycerol

25. Structure of a biological membrane
A lipid bilayer with associated proteins

26. Steroids The carbon skeleton of steroids is bent to form 4 fused rings
Cholesterol
Cholesterol is the “base steroid” from which your body produces other steroids
Estrogen
Testosterone
Estrogen & testosterone are also steroids

27. Nucleic Acids Store hereditary information
Contain information for making all the body’s proteins
Two types exist --- DNA & RNA

28. Amino acids - Proteins:
Building blocks of proteins.
R Group (side chains) determines the chemical properties of each amino acids.
Also determines how the protein folds and its biological function.
Functions as transport proteins, structural proteins, enzymes, antibodies, cell receptors.

29. Proteins as Enzymes
Many proteins act as biological catalysts or enzymes
Thousands of different enzymes exist in the body
Enzymes control the rate of chemical reactions by weakening bonds, thus lowering the amount of activation energy needed for the reaction -> Catalysator
-> No not interfere with the equilibrium of reaction
-> Enzymes are reusable !!!!

30. Enzymes:
Active site - a cleft or groove in an enzyme that binds the substrates of a reaction
The nature and arrangement of amino acids in the active site make it specific for only one type of substrate.
Egg white lysozyme

31. Macromolecules

32. Macromolecules

33. Concepts of Life Life is characterized by
Biological diversity: lichen, microbes, jellyfish, pine, hummingbirds, fly, gila monsters, & human beings
Chemical unity: living systems (on earth) obey the rules of physical and organic chemistry – there are no new principles

34. Life needs 3 things: (1) ENERGY, which it must know how to:
Extract
Transform
Utilize

35. The Energetics of Life
Photosynthetic organisms capture sunlight energy and use it to synthesize organic compounds
Organic compounds provide energy for all organisms

36. Using O2 to generate energy
2 H2O  O2 + 4e- + 4H+ (photosynthesis)
Glucose + 6O2  6CO2 + 6H2O + Energy

37. Glycolysis: the preferred way for the formation of ATP

38. Life needs (2) SIMPLE MOLECULES, which it must know how to:
Convert
Polymerize
Degrade

39. Life needs (3) CHEMICAL MECHANISMS, to:
Harness energy
Drive sequential chemical reactions
Synthesize & degrade macromolecules
Maintain a dynamic steady state
Self-assemble complex structures
Replicate accurately & efficiently
Maintain biochemical “order” vs outside

40. Trick: Life uses enzymes to speed up otherwise slow reactions

41. How does an enzyme do it, thermodynamically?

42. How does an enzyme do it, mechanistically?

43. Summary of Key Concepts

44. Biochemical Reactions
Metabolism: total sum of the chemical reaction happening in a living organism (highly coordinated and purposeful activity)
Anabolism- energy requiring biosynthetic pathways
Catabolism- degradation of fuel molecules and the production of energy for cellular function
All reactions are catalyzed by enzymes
The primary functions of metabolism are:
a. acquisition & utilization of energy
b. Synthesis of molecules needed for cell structure and
functioning (i.e. proteins, nucleic acids, lipids
c. Removal of waste products

45. Even though thousands of pathways sound very large and complex in a tiny cell:
The types of pathways are small
Mechanisms of biochemical pathways are simple
Reactions of central importance (for energy production & synthesis and degradation of major cell components) are relatively few in number

46. Energy for Cells Living cells are inherently unstable.
Constant flow of energy prevents them from becoming disorganized.
Cells obtains energy mainly by the oxidation of bio-molecules (e- transferred from 1 molecule to another and in doing so they lose energy)
This energy captured by cells & used to maintain highly organized cellular structure and functions

48. END