Dr. Madushani Silva (MBBS) North Colombo Teaching Hospital – Ragama
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- Dr. Madushani Silva (MBBS) North Colombo Teaching Hospital
Ragama
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- Biochemistry Chemistry of living organisms. The study of
biology at the molecular level.
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- 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
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- What is Biochemistry ? Biochemistry is the application of
chemistry to the study of biological processes at the cellular and
molecular level. A. Studying the structure and behavior of the
complex molecules found in biological material and B. the ways
these molecules interact to form cells, tissues and whole organism
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- Elements Make up all matter. 92 occur in nature. Identified by
names or chemical symbols (abbreviations of modern or Latin names).
Identified by number (based on structure of subunits or atoms).
Described and organized in periodic table.
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- Periodic Table
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- Molecules and Compounds Molecules Formed when two or more atoms
unite on the basis of their electron structures Can be made of like
atoms or atoms of different elements Compounds Composed of two or
more elements
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- 8 Many Important Biomolecules are Polymers Biopolymers -
macromolecules created by joining many smaller organic molecules
(monomers) Condensation reactions join monomers (H 2 O is removed
in the process)
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- 9 Linking Monomers Cells link monomers by a process called
dehydration synthesis (removing a molecule of water) This process
joins two sugar monomers to make a double sugar Remove H Remove OH
H 2 O Forms
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- 11 Breaking Down Polymers Cells break down macromolecules by a
process called hydrolysis (adding a molecule of water) Water added
to split a double sugar
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- Molecular Organisation of a cell 12
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- 13 Water Water is used in most reactions in the body Water is
called the universal solvent About 60-90 percent of an organism is
water
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- Biomolecules Carbohydrates Lipids Proteins Nucleic acid
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- 15 Biomolecules Structure Building block Simple sugar Amino
acid Nucleotide Fatty acid Macromolecule Polysaccharide Protein
(peptide) RNA or DNA Lipid Anabolic Catabolic
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- 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. 16
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- 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 17
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- Carbohydrates Composed of carbon, hydrogen, and oxygen. Sugars
Monosaccharides Ex. Glucose Disaccharides Ex. Sucrose
Polysaccharides Ex. Glycogen, Peptidoglycan
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- Carbohydrate - Glucose www.palaeos.com
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- Carbohydrate - Sucrose www.chm.bris.ac.uk
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- 21 Monosaccharides -Polysaccharides Glycosidic bonds connecting
glucose residues are in red Glucose - Cellulose
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- Carbohydrate - Peptidoglycan www.biologie.uni-hamburg.de
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- Carbohydrate - Glycogen www.elmhurst.edu
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- 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, steriods (cholestrol, sex hormones),
fat soluble vitamins. Functions Storage of energy in the form of
fat Membrane structures Insulation (thermal blanket) Synthesis of
hormones 24
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- Lipids Fatty Acids The building blocks of lipids.
biology.clc.uc.edu courses.cm.utexas.edu
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- 26 Triglyceride Glycerol Fatty Acid Chains
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- Lipids Examples are: Waxes Fats and oils Phospholipids Steroids
Phospholipid Cell Membrane. www.williamsclass.com
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- 28 Structure of a biological membrane A lipid bilayer with
associated proteins
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- 29 Steroids The carbon skeleton of steroids is bent to form 4
fused rings Cholesterol is the base steroid from which your body
produces other steroids Estrogen & testosterone are also
steroids Cholesterol Testosterone Estrogen Synthetic Anabolic
Steroids are variants of testosterone
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- Proteins Made up of polymers of amino acids. beads on a string.
20 primary amino acids exist. A polymer of 3 or more amino acids
forms a polypeptide.
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- Amino acids - Proteins: Amino acids: 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. 31
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- Proteins Primary Structure Linear sequence of amino acids.
Secondary Structure Form helices or sheets due to their structure.
Tertiary Structure A folded protein. Quaternary Structure 2 or more
polypeptide chains bonded together.
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- Protein Structure www.denizyuret.com
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- 34 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 !!!!
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- Enzymes Are proteins. Are considered biological catalysts.
Speed up a chemical reaction without being altered. Names often end
in - ase. Ex. Lipase, carbohydrase. Act on a substrate. Proteins,
including enzymes, can be denatured.
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- 36 Enzymes: Active site - a cleft or groove in an enzyme that
binds the substrates of a reaction Egg white lysozyme The nature
and arrangement of amino acids in the active site make it specific
for only one type of substrate. (accepts just one enaniomer)
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- Nucleic Acids DNA and RNA. (DNA - deoxyribonucleic acid, RNA -
ribonucleic acid). Is the hereditary molecule. Contains genes that
code for a certain product. DNA is translated into RNA which is
used to produce a protein or other product.
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- Nucleic Acid Structure DNA nucleotides Building blocks of DNA.
RNA nucleotides Building blocks of RNA.
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- Nucleic Acid Structure DNA Nitrogenous base Deoxyribose
Phosphate group RNA Nitrogenous base Ribose Phosphate group
www.microbelibrary.org
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- Nitrogenous Bases Adenine (A) Guanine (G) Cytosine (C) Thymine
(T) only DNA Uracil (U) only RNA DNA and RNA
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- Nitrogenous Bases A and G Purines (double- ring structures) C,
T, and U Pyrimidines (single-ring structures)
hyperphysics.phy-astr.gsu.edu
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- DNA Structure Nucleotides bond between sugar and phosphate
groups to form long polymers. Double-stranded DNA - The two
nucleotide polymers bind at the nitrogenous bases. Bonding forces
cause the double-stranded polymer to form a double helix.
www.genome.gov
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- DNA Structure James Watson (left) and Francis Crick (right)
discovered the double-helix structure of DNA and its process of
replication in the 1950s. www.achievement.org
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- DNA Replication Occurs during cell division. Both strands of
the double-helix unwind and replicate a complimentary strand. The
parent strand and new daughter strand form a new double-helix. DNA
polymerase is one enzyme used in replication process.
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- 45 Macromolecules
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- 46 Macromolecules
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- 47 Life needs 3 things : (1) ENERGY, which it must know how to:
Extract Transform Utilize
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- Glycolysis: the preferred way for the formation of ATP 48
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- 49 Life needs (2) SIMPLE MOLECULES, which it must know how to:
Convert Polymerize Degrade
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- 50 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
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- 51 Trick : Life uses enzymes to speed up otherwise slow
reactions
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- Biochemical Reactions Metabolism: total sum of the chemical
reaction happening in a living organism (highly coordinated and
purposeful activity) a. Anabolism- energy requiring biosynthetic
pathways b. 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, & CHO c. Removal of waste products 53
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- 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 54
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- 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 55
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