B.sc. biochemistry sem 1 introduction to biochemistry unit 4 metabolism and bioenergetics
1. introduction biochemistry
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Transcript of 1. introduction biochemistry
BiochemistryBiochemistry
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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
What is Biochemistry ?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:
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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Principles of BiochemistryPrinciples 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.
All organisms use the same type of molecules: carbohydrates, proteins, lipids & nucleic acids.
Instructions for growth, reproduction and developments for each organism is encoded in their DNA
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CellsCells
Basic building blocks of life
Smallest living unit of an organism
Grow, reproduce, use energy, adapt, respond to their environment
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
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Prokaryote CellProkaryote Cell
Eukaryote CellEukaryote Cell
OrganellesOrganelles
Biologically differentiated structures and living materials of Cytoplasm.
Essential for different bio-synthetic activities of the cell .
Also form the structural part of the cytoplasm Include:(1) Cell membrane (2) Endoplasmic reticulum-Rough and smooth (3) Mitochondria (4) Golgi apparatus (5) Centrosome with centrioles (6) Ribosomes (free and attached) (7) Lysosomes (8) Peroxisomes (9) Filaments (10) Microtubules (11) Vesicles
Non OrganellesNon Organelles
(1) Protein(2) Fat(3) Carbohydrate (Glycogen)(4) Water(5) Inorganic materials(6) Pigments like Melanin ,
lipofuscin(7) Cellular Products: Yolk &
Secretory granules
Characteristic Bio-membranes and Organelles
MitochondrionSurrounded by a double membrane with a series of foldscalled cristae. Functions in energy production through metabolism. Contains its own DNA, and is believed to have originated as a captured bacterium.
Plasma MembraneA lipid/protein/carbohydrate complex, providing a barrier and containing transport and signaling systems. NucleusDouble membrane surrounding the chromosomes and the nucleolus. Pores allow specific communication with the cytoplasm. The nucleolus is a site for synthesis of RNA making up the ribosome
Chloroplasts (plastids)Surrounded by a double membrane, containing stacked thylakoid membranes. Responsible for photosynthesis, the trapping of light energy for the synthesis of sugars. Contains DNA, and like mitochondria is believed to have originated as a captured bacterium.
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Rough endoplasmic reticulum (RER)A network of interconnected membranes forming channels within the cell. Covered with ribosomes (causing the "rough" appearance) which are in the process of synthesizing proteins for secretion or localization in membranes.RibosomesProtein and RNA complex responsible for protein synthesis
Smooth endoplasmic reticulum (SER)A network of interconnected membranes forming channels within the cell. A site for synthesis and metabolism of lipids. Also contains enzymes for detoxifying chemicals including drugs and pesticides.
Golgi apparatusA series of stacked membranes. Vesicles (small membrane surrounded bags) carry materials from the RER to the Golgi apparatus. Vesicles move between the stacks while the proteins are "processed" to a mature form. Vesicles then carry newly formed membrane and secreted proteins to their final destinations including secretion or membrane localization. Lysosymes
A membrane bound organelle that is responsible for degrading proteins and membranes in the cell, and also helps degrade materials ingested by the cell.
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VacuolesMembrane surrounded "bags" that contain water and storage materials in plants.
Peroxisomes or MicrobodiesProduce and degrade hydrogen peroxide, a toxic compound that can be produced during metabolism.
Cell wallPlants have a rigid cell wall in addition to their cell membranes
Cytoplasmenclosed by the plasma membrane, liquid portion called cytosol and it houses the membranous organelles.
CytoskeletonArrays of protein filaments in the cytosol. Gives the cell its shape and provides basis for movement. E.g. microtubules and microfilaments.
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Comparison between prokaryotic and Comparison between prokaryotic and eukaryotic cellseukaryotic cells
Characteristics prokaryotic eukaryotic
Size small (1-10um) large(10-100um
Cell membrane rigid cell wall flexible plasma membrane
Sub-cellular organelles
Absent Distinct organelles found
Nucleus not well defined, DNA is found
Nucleus is well defined, DNA is associated with histones
Energy Metabolism Mitochondria absent
Mitochondria present
Cell division usually fission & no mitosis
Mitosis
Cytoplasm organelles & cytoskeleton absent
contain organelles & cytoskeleton
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Bio-moleculesBio-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.
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Many Important Biomolecules are Many Important Biomolecules are PolymersPolymers
p ro te in com plex
p ro te in su b un it
a m ino ac id
m em b rane
p ho sp ho lip id
fa tty a c id
ce ll w a ll
ce llu lo se
g lu co se
ch ro m o som e
D N A
n uc leo tidemonomer
polymer
supramolecularstructure
lipids proteins carbo nucleic acids
LipidsLipids
m em b rane
p ho sp ho lip id
fa tty a c idmonomer
polymer
supramolecularstructure
ProteinsProteins
monomer
polymer
supramolecularstructure Enzyme complex
protein subunit
amino acid
CarbohydratesCarbohydrates
ce ll w a ll
ce llu lo se
g lu co semonomer
polymer
supramolecularstructure
ch ro m a tin
D N A
n uc leo tidemonomer
polymer
supramolecularstructure
Nucleic AcidsNucleic Acids
Common theme:
Monomers form polymers through condensations
Polymers are broken down through hydrolysis.
Linking MonomersLinking Monomers
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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
H2O Forms
Breaking Down PolymersBreaking Down PolymersCells break down
macromolecules by a process called hydrolysis (adding a molecule of water)
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Water added to split a double sugar
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