2. DR.MITHAL ABD UL-KAREEM College of dentistry/Ibn sina universityBY
DR.MITHAL ABD UL-KAREEM
College of dentistry/Ibn sina university

3. Objectives Compare and contrast the structure of atoms and compounds
Differentiate between chemistry and Biochemistry
Define Chemical Reactions
Define Biochemistry and its Relation to other science

4. Our world is made up of an enormous variety of both naturally-occurring and man-made elements and compounds.
From our galaxy to the earth’s inner crust to our own bodies, everything is made from elementary parts or substances

5. Chemistry is a science that attempts to organize and explain, in a systematic and logical manner, knowledge about the existence, purpose and interaction of these substances.

6. Chemistry
Atoms
The atom is the smallest unit of matter that enters into chemical reactions.
Atoms interact to form molecules.

7. The Structure of Atoms Atoms are composed of: Nucleus: Protons:
positively charged particles,
Determine element
Neutrons:
no charge particles,
have a mass slightly larger than that of a proton
Electrons:
negatively charged particles,
Electrons are arranged in electron shells corresponding to different energy levels

8. The Structure of Atoms
Isotopes of an element are atoms with different numbers of neutrons..

10. IONS
An ion is a charged species formed from a neutral atom or molecule when electrons
are gained or lost as the result of a chemical change. The number of positively charged
protons in the nucleus of an atom remains the same during ordinary chemical changes
(called chemical reactions), but negatively charged electrons may be lost or gained.
The loss of one or more electrons from a neutral atom results in a cation,
an ion with a net positive charge. For example, a sodium atom (Na) can readily lose an electron
to become sodium cation, which is represented by Na :
Na ATOM Na ION
11 protons protons
11 electrons electrons

11. Why atoms of different elements gain (or lose) a specific number of
electrons.

12. How Atoms Form Molecules? Chemical Bonds
Chemical bond - the forces holding atoms in molecules ( the attraction between atoms)
A molecule – any two or more atoms held together
O H2
A compound - at least two different kinds of atoms chemically bonded. H2O

14. Chemical Reactions
Chemical reactions involve the making or breaking of bonds between atoms.
A change in chemical energy occurs during a chemical reaction.
Endergonic reactions absorb energy.
Synthesis reaction (making bonds)
Exergonic reactions release energy.
Decomposition Reactions (breaking bonds)

15. 1. Synthesis Reactions:-
Occur when atoms, ions, or molecules combine to form new, larger molecules
Anabolism is the synthesis of molecules in a cell – use of energy
e.g.(growth)
+ Energy A + B  AB
Atom, ion, or molecule A
Atom, ion, or molecule B
New molecule AB

16. 2. Decomposition Reactions
Occur when a molecule is split into smaller molecules, ions, or atoms.
Catabolism is the decomposition reactions in a cell – release energy.e.g.(digestion)
Breaks down into AB  A + B
+ Energy
New molecule AB
Atom, ion, or molecule A
Atom, ion, or molecule B

17. Life fundamental feature:
Growth - through metabolism (catabolism and anabolism) - the set of chemical reactions that occur in living organisms in order to maintain life
Reproduction - process by which organisms generate new individuals of the same kind - heritable genetic information (the molecular basis for genes is deoxyribonucleic acid (DNA))

18. Important Biological Molecules
1-Organic compounds always contain Carbon-Hydrogen connected.
Methane CH4
(organic)
2-Inorganic compounds typically lack carbon and
Carbon-Hydrogen connected.
Carbonic-acid H2CO3
(inorganic)

19. Important Biological Molecules
Inorganic compounds typically lack carbon and Carbon-Hydrogen connected.
2. Organic compounds always contain Carbon-Hydrogen connected.
Carbonic-acid H2CO3
(inorganic)
Methane CH4
(organic)

20. What is “Biochemistry
Biochemistry-biological chemistry, is the study of chemical processes within, and relating to, living organisms.
And it is a branch of medical science that seeks to describe the structure,orgamization and function of living matter in molecular term.

21. examples of living systems

22. Biology is Varied and Complex

23. Biology is Varied and Complex

24. knowledge of biochemistry is essential to all life science

25. physiology
 immunology
 pharmacology
 pathology
 microbiology

26. Biochemistry in Relation to Dentistry
The aims, attitudes and techniques of biochemistry are as relevant to dentistry as to medicine or to any aspect of biology. To understand the true nature of dental disease. All diseases have a biochemical basis.

27. References 
1-R.K. Murray et al.Biochemistry text:, “Harper’s Biochemistry, 29th Edition”, Appleton &Lange (Stamford, Conn., 2012)
2-David L. Nelson, Michael M. cox Lehninger principles of
2008))biochemistry ,5th edition
3- Raymond Chang, chemistry, 8th edition, Mc graw Hill, 2005

28. Next lecture
Review of atoms and chemical bonds

29. Thank you