Understanding Biochemistry: The Essential Study of Biological Molecules and Life Structures
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Introduction
Biochemistry is a pivotal branch of science that delves into the chemical composition and structure of living organisms, along with the myriad of biochemical reactions occurring within them. Central to biochemistry are biomolecules — the complex organic molecules that serve as the building blocks and energy sources for life. In this article, we will navigate through the intricate relationships between biomolecules, cells, and the life processes they support, focusing on key concepts such as carbohydrates, proteins, and nucleic acids.
What Are Biomolecules?
Biomolecules are essential for maintaining life and driving the growth and development of living organisms. They can be categorized into four main classes: carbohydrates, proteins, lipids, and nucleic acids. Each biomolecule plays a crucial role in biological functions and supports cellular processes.
Classification of Biomolecules
- Carbohydrates: Energy sources and structural components.
- Proteins: Functional molecules that facilitate various biochemical reactions.
- Lipids: Energy storage, cellular membranes, and signaling molecules.
- Nucleic Acids: Genetic information storage and transfer.
The Fundamental Unit of Life: The Cell
The cell is the smallest functional unit of life. Although invisible to the naked eye, cells can be observed under a microscope, revealing their intricate structures and functions. Cells are essential for growth, metabolism, and response to environmental signals. They contain various organelles and biomolecules necessary for life, such as proteins and nucleic acids.
Cellular Structure
- Organelles: Specialized structures within cells (e.g., nucleus, mitochondria).
- Biomolecules: Carbohydrates, proteins, lipids, and nucleic acids.
- Cell Membrane: Encloses the cell and regulates the passage of substances.
Carbohydrates: Energy and Structure
Carbohydrates are organic compounds that serve as a primary energy source. They are classified based on their size and solubility:
Types of Carbohydrates
- Monosaccharides: Simple sugars (e.g., glucose, fructose).
- Oligosaccharides: A few monosaccharide units (2-9) linked together (e.g., sucrose).
- Polysaccharides: Long chains of monosaccharide units (e.g., starch, glycogen, cellulose).
Functions of Carbohydrates
- Energy storage (e.g., starch in plants, glycogen in animals).
- Structural components (e.g., cellulose in plant cell walls).
- Source of energy for metabolic processes.
Proteins: The Workhorses of the Cell
Proteins are complex biomolecules composed of amino acids. They play diverse roles in biological systems, acting as enzymes, hormones, structural components, and antibodies.
Structure of Proteins
- Primary Structure: Sequence of amino acids.
- Secondary Structure: Folding patterns (e.g., alpha-helix, beta-pleated).
- Tertiary Structure: 3D shape of a single polypeptide chain.
- Quaternary Structure: Assembly of multiple polypeptide chains.
Functions of Proteins
- Catalyzing metabolic reactions (enzymes).
- Transporting molecules (hemoglobin).
- Providing structure (collagen in connective tissues).
Nucleic Acids: The Genetic Blueprint
Nucleic acids, including DNA and RNA, are crucial for storing and transmitting genetic information. They are polymers of nucleotides composed of a sugar, phosphate group, and nitrogenous base.
Types of Nucleic Acids
- DNA (Deoxyribonucleic Acid): Carries genetic information and is composed of deoxyribose sugar.
- RNA (Ribonucleic Acid): Plays roles in protein synthesis and gene expression, containing ribose sugar.
Functions of Nucleic Acids
- Genetic information storage.
- Protein synthesis through transcription and translation processes.
Enzymes: Biological Catalysts
Enzymes are specialized proteins that accelerate biochemical reactions without being consumed in the process. Their specificity and efficiency make them vital for metabolic regulation.
Characteristics of Enzymes
- Highly specific for substrates.
- Lower activation energy required for reactions.
- Function optimally under specific conditions (temperature and pH).
Conclusion
Biochemistry serves as a foundational field that connects chemistry and biology, enhancing our understanding of living organisms. By studying the structures and functions of biomolecules like carbohydrates, proteins, and nucleic acids, we gain insights into the complex processes that sustain life. Whether exploring cellular metabolism or the mechanisms of enzyme action, the field of biochemistry continues to unravel the intricacies of biological systems, paving the way for advancements in medicine, nutrition, and biotechnology.
of science that deals with the study of the chemical composition and the structure of living organisms
the complex organic molecules which form the basis of life which build up living organisms and are
also required for their growth and maintenance are called biomolecules biomolecules are related to the living
divide to produce cells these daughter cells can further divide to produce new progeny of cells
cells may be combined to form tissues tissues may be grouped into organs and organs may be combined into organisms
a living cell contains about 50 elements the most abundant substance in a living cell is water which amounts to about 70
our everyday life are defined as polyhydroxy aldehydes or polyhydroxy ketones or the compounds
which can be hydrolyzed to them they are also known as saccharides these are the ultimate source of most of
carbohydrates are classified into three major categories depending upon their behavior towards
hydrolysis give two to nine units of monosaccharides they have subcategories depending upon
the actual number of monosaccharide units formed by the hydrolysis of a particular oligosaccharide
disaccharides give two units of monosaccharides on hydrolysis for example maltose and sucrose
they can be further classified into different categories depending upon the number of carbon
ripe grapes contain up to 20 glucose in combined state glucose is present in disaccharides and
by hydrolysis of cane sugar it can be prepared by hydrolysis of cane sugar in the presence of alcohol
by hydrolysis of starch on commercial scale it is prepared by hydrolysis of starch by boiling it with
intersection of the lines are not shown with hydrogen cyanide glucose forms an addition product called
contains five hydroxy groups with mild oxidizing agent glucose is oxidized to gluconic acid
with strong oxidizing agent glucose is oxidized to glucaric acid on reduction with sodium amalgam glucose
solution of an alkali it undergoes reversible isomerization to form an equilibrium mixture of
d-glucose d-mannose and d-fructose it reduces tolerance reagent failing solution and benedict solution
cyclic structure of glucose some evidence suggests that the open chain structure of d-glucose exists
alpha and beta the alpha form of glucose is obtained by crystallization from a concentrated
solution of glucose at 303 kelvin while the beta form is obtained by crystallization from hot and saturated
the change in specific rotation of an optically active compound to an equilibrium value is known as muta
structures as a result of cyclization the enumeric carbon becomes asymmetric and the newly formed o h group may be
either on the left or on the right in fissure projection this results in the formation of two
fructose is a simple monosaccharide found in many plants it is one of the three dietary monosaccharides along with
it also exists in two cyclic forms which are formed by reaction of o h and c5 to ketonic group at c2
those carbohydrates which yield two units of monosaccharide on hydrolysis are called disaccharides
non-reducing sugars if the two monosaccharide units are linked through their respective carbonyl
sucrose is the most widely occurring disaccharide and is found in all photosynthetic plants
it gives an equimolar mixture of d-glucose and d-fructose sucrose is dextro rotatory with specific
sucrose gives an equimolar mixture of dextro rotatory glucose and levo rotatory for maltose
it tastes sweet and it is not found freely in nature it has the ability to reduce the felling
lactose is a disaccharide sugar derived from galactose and glucose lactose crystals have a characteristics tomahawk
consisting of glucose monomeric units is called a glucan three important polysaccharides in which
energy storage in animals and fungi in humans it is made and stored primarily in the cells of the liver and
the muscles and functions as the secondary long-term energy storage it is a polymer of glucose with 1 4
alpha glucosidic linkage and having considerable chain branching it is white powder soluble in water it
proteins are the most abundant biomolecules of the living system chief sources of proteins are milk
they occur in every part of the body and form the fundamental basis of structure and functions of life
they're also required for growth and maintenance of body proteins perform a vast array of
these are amino substituted carboxylic acids the alpha amino acids are the building blocks of peptides and proteins
amino acids are classified as neutral acidic or basic depending upon the relative number of
if the number of amino groups and carboxyl groups is equal in the molecule the amino acid is neutral
if the number of amino groups is less than carboxyl groups then the amino acid is acidic for
amino acids can be synthesized by all living organisms plants and animals the amino acids which can be synthesized
for an adult human there are 10 essential amino acids deficiency of essential amino acids in
enzymes can cause alpha amino acids to polymerize to give peptides through elimination of water molecule
the conh linkage that forms between the amino acids is known as a peptide bond or peptide linkage amino acids when
acid residues are called polypeptides polypeptides are linear polymers one end of a polypeptide chain
terminates in an amino acid residue that has an nh2 group is known as n-terminal the other terminates in an amino acid
the amino acid sequence is specified by using three letter amino acid abbreviations for the respective amino
acids and connected by hyphens classification of proteins proteins can be classified into two
and are held together side by side at many points by hydrogen and disulfide bonds a thread-like structure is formed
is folded around in such a manner so as to give the protein molecule almost spheroidal shape
they have weak intermolecular forces they are soluble in water they catalyze biological reactions
acids are arranged in a protein is called its primary structure any change in the sequence of amino
it refers to shape in which a long polypeptide chain exists they have two types of structures
regular coiling of polypeptide chain which is stabilized by intramolecular hydrogen bonding
peptide chains are stretched to nearly maximum extension and then arranged side by side and held
quaternary structure some of the proteins are composed of two or more polypeptide chains referred to
known as quaternary structure enzymes are biological catalysts they are generally globular proteins which
digestive tract it would take about 50 years to digest a single meal some common and important
characteristics of enzymes are their action is highly specific each enzyme catalyzes only a specific
their efficiency is maximum at about 310k temperature at a moderate ph even very small amounts of an enzyme are
sufficient to speed up a reaction mechanism of enzyme action the substrate molecule binds itself to
binding results in the formation of enzyme substrate complex enzymes lower down the activation energy
when hydrolysis takes place in presence of sucrase enzyme humans their sources and deficiency
vitamin b2 is soluble in water it is stable to heat and destroyed by light deficiency of vitamin b6 causes nervous
it is red crystalline in nature vitamin c is soluble in water it is destroyed by cooking and exposure to air
vitamin d is soluble in fats and oils but insoluble in water it is stable towards heat and oxidation
vitamin e is soluble in fats and oils but insoluble in water it is stable to heat and oxidation
nucleic acids are long chain polymers of nucleotides they play an important role in transmission of hereditary
and ribonucleic acid nucleic acids contain two types of n-containing heterocyclic bases purine
they are the carrier of genetic characteristics and send information and instruction to the cell for the
bases from pyrimidine bases and two bases from purine base a phosphate group is present at c5 of
rna is associated with the process of learning and memory storage and helps in biosynthesis of protein
produces two identical molecules of itself in the nucleus of the cell is called replication
this is brought about in two steps transcription which is copying of sequence of bases from the dna strand on
the rna molecule is called transcription translation in this process mrna directs protein synthesis in the