🧬
Büchner Brothers (1899) - Proved that
Lecture 01 cell-free yeast extracts can ferment
sugar - birth of modern biochemistry.
INTRODUCTION TO BIOCHEMISTRY
-ˋˏ✄┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
Biochemistry - branch of science that
studies chemical composition, structure, EARLY TO MID-20TH CENTURY
and reactions. ADVANCES
Molecules of life: Proteins, Carbohydrates,
Lipids, and Nucleic acids. • Identified citric acid cycle, urea cycle,
Chemical process in living organisms: and vitamin-derived coenzymes. (thiamin,
Biomolecules pyrophosphate, riboflavin, coenzyme A,
Biochemical processes sustain life and coenzyme 2, cobamides)
responds changes in the environment • 1950s: mapped pathways for
carbohydrates, amino acids, lipids, and
-ˋˏ✄┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈ pentoses.
• Developed research tools:
RELATIONSHIP OF BIOCHEMISTRY TO ultracentrifugation, chromatography,
MEDICINE radioisotope tracers, X-ray crystallography.
How Biochemistry Helps Medicine -ˋˏ✄┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
• Explains the molecular causes of diseases
• Helps in diagnosing illnesses by identifying DISEASE AS A WINDOW TO
chemical changes in the body BIOCHEMISTRY
• Guides the development of medicines and
treatments. • Protein stucture & disease: sickle cell
anemia showed that a single amino acid
How Medicine Helps Biochemistry change can cause illness.
• Medical cases and patient problems • Genetic diseases: Archibald Ganrod's
present scientists with new questions to inborn errors of metabolism-alkaptonuria,
study. albinism, cystinuria, pentosuria.
• Studying disease has led to the discovery • Modern examples: Familial
of new biochemical pathways and hypocholesterolemia revealed mechanisms
molecules. of cholesterol.
-ˋˏ✄┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈ -ˋˏ✄┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
NORMAL BIOCHEMICAL (Processes &.
HISTORY OF BIOCHEMISTRY Health)
Ancient knowledge - Humans knew yeast • WHO definition of health: complete
could convert sugar to alcohol (brewing, physical, mental, and social well-being—
winemaking) not just absence of disease.
Louis Pasteur (1800s) - Believed
fermentation required intact living cells.
• Biochemical view: Health exists when all Molecular Diagnostics and Systems
cellular reactions proceed at rates that Biology: Enhance disease detection and
support survival under stress. understanding.
• Nutrition link: requires optimal intake of Synthetic Biology: Potential to
vitamins, essential amino acids, essential revolutionize disease diagnosis, treatment,
fatty acids, minerals, and water. and prevention.
• Preventive medicine: Nutritional
strategies help prevent atherosclerosis, ⏔⏔⏔⏔⏔⏔⏔ ᧔ෆ ꒱ ⏔⏔⏔⏔⏔⏔⏔
cancer, and other diseases.
THE CELL
Most diseases have a biochemical basis
Causes include: • basic structural, functional, and biological
• Genetic defects in DNA, proteins, or units of all living organisms.
enzymes. • acts as a biochemical factory, carrying out
• Electrolyte imbalances. thousands of chemical reactions essential
• Poor nutrient absorption. for survival.
-ˋˏ✄┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈ • In eukaryotic cells (such as human cells),
most are multicellular organisms. They are
HUMAN GENOME PROJECT (HGP) plants, animals, fungi, pro-tozoa, uni-cellular
IMPACT yeast and true algae.
• In prokaryotic cells (simple, no nucleus,
Completed: 2003 (50 years after DNA and membrane bound organelles)
double helix discovery) They contain a cell wall and cytosol is not
divided into compartments. Examples are
Achievements: bacteria, primitive green algae and archaea
bacteria.
• Identified disease-related genes.
-ˋˏ✄┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-ˋˏ✄┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
NUCLEUS - The Information Center
RISE OF THE “-OMICS” FIELDS
Description:
• Transcriptomics: RNA transcript analysis Largest organelle, enclosed by a double
• Proteomics: Study of all cellular proteins membrane called the nuclear envelope
• Bioinformatics: - contains DNA packaged as chromatin and
the nucleolus (site of rRNA synthesis)
EMERGING RELATED FIELDS
(Biotechnology, bioengineering, Biochemical processes:
nanotechnology, stem cell biology, • DNA replication - making a complete
bioethics) copy of genetic material before cell division.
• Transcription - production of mRNA,
Gene therapy: Still evolving but holds tRNA, and rRNA from DNA templates.
promise.
• RNA processing - capping, splicing, • Calcium storage in muscle cells
polyadenylation, to create mature RNA. (sarcoplasmic reticulum)
• Gene regulation - controlled by • Glycogen metabolism in liver cells.
transcription factors and chromatin
remodeling. -ˋˏ✄┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-ˋˏ✄┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈ GOLGI APPARATUS - Packaging &
Distribution.
RIBOSOMES - Protein Factories • Flattened sacs with cis (receiving) and
• Non-membranous particles made of rRNA trans (shipping) faces.
and proteins.
• Found-free in cytosol or attached to rough Biochemical processes:
ER. • modification of proteins and lipids
• sorting
Biochemical processes:
• Translation - decoding mRNA into a -ˋˏ✄┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
specific amino acid sequence.
• Peptide bond formation via peptidyl MITOCHONDRIA - Powerhouse of the cell
transferase activity.
• In RER-bound ribosomes: cotranslational Biochemical processes:
insertion into membranes or ER lumen. • Citric Acid Cycle (TCA) - Produces NADH
and FADH2 from acetyl-COA
-ˋˏ✄┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈ • Oxidative Phosporylation - ATP generation
via electron transport chain
ENDOPLASMIC RETICULUM (ER) • β-oxidation of fatty acids
• Apoptosis initiation via cytochrome c
Rough ER (RER) release.
• network of sacs covered with ribosomes;
continuous with nuclear envelope. -ˋˏ✄┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
Biochemical processes: LYSOSOMES - Digestive Units
• synthesis of secretory and membrane • suicide bag of the cell
proteins. • membrane-bound organelles with acidic
• inital glycosylation and folding of proteins. interior and hydrolytic enzymes.
Smooth ER (SER) Biochemical Processes:
• tubular structure without ribosomes. • Breakdown of proteins, lipids, nucleic
acids, carbohydrates.
Biochemical processes: • Authophagy - digestion of damaged
• Lipid and steroid synthesis (cholesterol, organelles.
steroid, hormones) • Destruction of pathogens in phagocytic
• Detoxification via cytochrome P450 cells.
enzymes.
-ˋˏ✄┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
PEROXISOMES - Detoxification Centers
• small vesicles with oxidative enzymes like
catalase.
Biochemical Processes:
• β-oxidation of very long-chain fatty acids
• Detoxification of hydrogen peroxide
• Synthesis of plasmalogens (important for
myelin - protein present in nerves)
