السبت، 28 أغسطس 2010

biochemistry

BIOCHEMISTRY
• BIOCHEMISTRY IS THE SCIENCE CONCERNED WITH THE CHEMICAL BASIS OF LIFE (GK BIOS “LIFE”).
• BIOCHEMISTRY IS A SPECIAL BRANCH OF ORGANIC CHEMISTRY THAT DEALS WITH MATTER INSIDE THE LIVING CELL CALLED PROTOPLASM.
• PROTOPLASM IS AN ENORMOUSLY COMPLEX MIXTURE OF ORGANIC COMPOUNDS WHERE HIGH LEVELS OF CHEMICAL ACTIVITY OCCUR.
THE AIM OF BIOCHEMISTRY
 IS TO DESCRIBE AND EXPLAIN IN MOLECULAR TERMS, ALL CHEMICAL PROCESSES OF LIVING CELLS
 KNOWLEDGE OF BIOCHEMISTRY IS ESSENTIAL TO ALL LIFE SCIENCES
GENETICS …………..NUCLEIC ACIDS
PHARMACOLOGY …….DRUGS METABOLIZED BY ENZYME CATALYZED REACTIONS
TOXICOLOGY ………..POISONS ACT ON BIOCHEMICAL REACTIONS OR PROCESSES.
 IMMUNOLOGY …….EMPLOYS NUMEROUS BIOCHEMICAL TECHNIQUES.
 PATHOLOGY, MICROBIOLOGY, ZOOLOGY AND BOTANY USE BIOCHEMICAL APPROACHES.
 BARRIERS AMONG LIFE SCIENCES ARE BREAKING DOWN AND BIOCHEMISTRY IS INCREASINGLY BECOMING THEIR COMMON LANGUAGE.
BIOCHEMISTRY AND MEDICINE
 THE INTERRELATIONSHIP OF BIOCHEMISTRY AND MEDICINE IS A WIDE TWO WAY STREET.

Nucleic acid proteins Biochemistry lipids carbohydrates
-------- ↕ -------------------- ↕ ------------------ ↕ ---------------- ↕ -----------------------↕----
Genetic disease sickle cell anemia Medicine atherosclerosis diabetes
mellitus
 NORMAL BIOCHEMICAL PROCESSES ARE THE BASIS OF HEALTH.
 BIOCHEMICAL RESEARCH HAS IMPACT ON NUTRITION AND PREVENTIVE MEDICINE
 ALL DISEASE HAS BIOCHEMICAL BASIS
 BIOCHEMICAL STUDIES CONTRIBUTE TO DIAGNOSIS, PROGNOSIS, AND TREATMENT.
ELEMENTS IN BIOMOLECULES
 ALL STUDENTS OF LIFE SCIENCES MUST HAVE A FUNDAMENTAL UNDERSTANDING OF ORGANIC CHEMISTRY AND BIOCHEMISTRY.
Organic Chemistry
• ORGANIC CHEMISTRY IS THE STUDY OF CARBON COMPOUNDS.
• ORGANIC COMPOUNDS ARE COMPOUNDS COMPOSED PRIMARILY OF A CARBON SKELETON.
• ALL LIVING THINGS ARE COMPOSED OF ORGANIC COMPOUNDS.
• 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 COVALENTLY BOND WITH UP TO FOUR OTHER ATOMS.

Carbon can form immensely diverse compounds, from simple to complex.


 THE CELL IS THE UNIT OF LIFE IN ALL LIVING ORGANISM BACTERIA (UNICELLULAR) & ANIMALS (MULTICELLULAR).
 ALL CELLS HAVE A LIMITING OUTER MEMBRANE (PLASMA MEMBRANE) THAT:
A. DETERMINE THE SPACE OCCUPIED
B. SEPARATE THE INTERNAL ENVIRONMENT FROM THE SURROUNDING ENVIRONMENT
C. MEMBRANES AND THEIR COMPONENTS ARE THE LINK TO THE OUTSIDE E.G. CONTROLLING THE MOVEMENT OF SUBSTANCES IN AND OUT OF THE CELL AND SERVING AS MEANS OF COMMUNICATION.



Types of cells:
1/ PROKARYOTES
• DON’T HAVE NUCLEUS OR INTERNAL MEMBRANE STRUCTURES (BACTERIA).
• DNA SEGREGATED INTO DISCRETE MASS, THE NUCLEOID REGION NOT SURROUNDED BY MEMBRANE.
• HAVE VARIETY OF SHAPES AND SIZES, USUALLY WITH A VOLUME 1/1000 TO 1/10.000 THAT OF EUKARYOTIC CELLS.
2/ EUKARYOTES
• HAVE DEFINED NUCLEUS AND INTRACELLULAR ORGANELLES SURROUNDED BY MEMBRANES (YEAST, FUNGI, PLANTS & ANIMALS).
• DISTINCT SUBCELLULAR COMPARTMENTS PERMIT A UNIQUE DEGREE OF SUBCELLULAR ORGANIZATION.
• BY COMPARTMENTALIZATION DIFFERENT CHEMICAL REACTIONS THAT REQUIRE DIFFERENT ENVIRONMENTS CAN OCCUR SIMULTANEOUSLY.
 BESIDES STRUCTURAL DISTINCTIONS THERE ARE SIGNIFICANT DIFFERENCES IN CHEMICAL COMPOSITION AND BIOCHEMICAL ACTIVITIES, E.G.
• PROKARYOTES DON'T HAVE HISTONES
There are also differences in:
A. THE RNA-PROTEIN COMPLEXES INVOLVED IN THE BIOSYNTHESIS OF PROTEINS
B. THE ENZYME CONTENT.

 EUKARYOTIC CELLS CONTAIN WELL-DEFINED CELLULAR ORGANELLES SUCH AS NUCLEUS, MITOCHONDRIA, LYSOSOMES & PEROXISOMES.
 THE LIPID NATURE OF CELLULAR MEMBRANES PREVENTS MOVEMENT OF MANY MOLECULES INCLUDING WATER ACROSS THEM.
 SPECIFIC MECHANISMS FOR TRANSPORTATION OF LARGE OR SMALL, CHARGED OR UNCHARGED MOLECULES ARE AVAILABLE.
 THIS ALLOW MEMBRANES TO MODULATE CONCENTRATIONS OF SUBSTANCES IN VARIOUS COMPARTMENTS.
 PARTITIONING OF ACTIVITIES AND COMPONENTS IN MEMBRANE- ENCLOSED COMPARTMENTS AND ORGANELLES HAS A NUMBER OF ADVANTAGES FOR THE ECONOMY OF THE CELL.
E.G.
- SEQUESTERING OF SUBSTANCES AND COFACTORS WHERE THEY ARE REQUIRED.
- ADJUSTMENT OF PH AND IONIC COMPOSITION FOR MAXIMUM ACTIVITY OF BIOLOGICAL PROCESSES.