Biology is the scientific study of life and living organisms. It explores the structure, function, development, behavior, and evolution of living things through various subdisciplines. The fundamental units of biology are the cell, genes, and evolution. Biology seeks to understand the mechanisms that allow living things to maintain their internal organization and adapt to environmental changes.

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Biology
Unit-1
Q1) Explain Biology as a scientific discipline?
A1) Biology is the branch of natural science that deals with studies of life
and living organisms, that include their physical structure, chemical
process, molecular interactions, physiological mechanisms, development
and evolution. Despite the complex involved in the science, there are
certain concepts that consolidate it into a single, coherent field. Biology
assumes the cell as the basic unit of life, genes as the basic unit of heredity,
and evolution as the engine that propels. The creation and extinction
of species.
Biology derives its word from the ancient Greek words
of βίος; Romanisedbios meaning "life" and -λογία; Romanisedlogia (-logy)
meaning "branch of study" or "to speak". Those combined make the Greek
word βιολογία; Romanisedbiología meaning biology (Study of Life). All
sciences are equally important in that they all expand our collective
understanding of the universe in different areas.
That being said, there is a varying level of difficulty associated with
different sciences when we get past the basics. The advanced concepts in
physics, like general relativity and quantum mechanics require a very high
level of fluency in mathematics that the other sciences. Even the greatest
physicists have claimed to have difficulty understanding the implications of
these complex theories. However, we can understand the most
complicated concepts in biology using only one language, like English or
German. In order to fully understand physics or math, we must also learn
the language of mathematics at its highest level. Thus, biology does not
make it any more or less important but it definitely adds a whole new level
of study and discovery.
Q2) Mention the fundamental differences between camera and eye?
A2) A camera is a man-made device that records images in a tangible
format that may be saved for later use. It is used to create not only

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photographs but also videos. The word “camera” is derived from Latin
word “camera obscura,” which meaning “dark chamber.”
The human eye is an organ that creates images and sends them to the
brain to be interpreted. It has a ‘cornea’ covering on the outside that
reflects light. It also has an internal lens that dilates and contracts in
response to the light intensity.
Human Eye Camera
The human eye is made up of
the natural nerves and organic
components.
A camera is made up of artificial
materials and components.
Image is not recorded by Human eyes. Camera can record the image.
Blind spot is present in human eyes Blind spot is not present in
camera.
Pupil controls the focus in the human
eyes.
Lens controls the focus in the
camera.
3D image is processed by the human
eye.
2D image is processed by the
camera.

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Q3) Explain the Brownian motion with examples?
A3) Brownian motion is the random, movement of particles that cannot be
controlled in a fluid as they constantly collide with other molecules
(Mitchell and Kagura, 2006). Brownian motion is thus a part responsible of
the ability of movement in bacteria that do not encode or express motility
movements, such as Streptococcus and Klebsiella species. Brownian
motion can also affect “deliberate” movement exhibited by naturally
motile bacteria that harbour pili or flagella. For example, an Escherichia
coli cell that is swimming toward an area of higher oxygen concentration
may fall “off-track” if it physically encounters a particle moving by
Brownian motion or if such a particle(s) obstructs the bacterial cell’s path
of motion. This form of “interference” adds to the stochasticity with which
bacterial direction can change.
Brownian motion takes its name from the Scottish botanist Robert Brown,
who observed pollen grains moving randomly in water. He described the
motion in 1827 but was unable to explain it. While pedes is takes its name
from Brown, he was not the first person to describe it. The Roman poet
Lucretius describes the motion of dust particles around the year 60 B.C.,
which he used as evidence of atoms.
Examples include:
 The motion of pollen grains on still water

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 Movement of dust motes in a room (although largely affected by air
currents)
 Diffusion of pollutants in the air
 Diffusion of calcium through bones
 Movement of "holes" of electrical charge in semiconductors
Q5) Draw a comparison between the flying bird and the Aircraft?
A5) Birds and aircraft are both capable of flying, but they do so in different
ways and for different purposes. Here are some key differences between
the two:
1. Mechanisms of flight: Birds use their wings to generate lift and thrust,
while aircraft rely on engines and airfoils to generate lift and move
forward. Birds also have a lightweight skeleton and strong muscles,
which allow them to generate the necessary forces for flight, while
aircraft need engines and other mechanical components to provide
power.
2. Control and stability: Birds have the ability to control their flight by
adjusting the shape of their wings and using their tail feathers for
stability. In contrast, aircraft use a complex system of controls,
including flaps, ailerons, elevators, and rudder, to control their flight.
3. Range and speed: While birds can fly long distances and reach high
speeds, their range and speed are limited by their energy reserves and
the size of their wings. In contrast, aircraft have much greater range
and speed due to the power of their engines and the efficiency of
their airfoils.
4. Purpose of flight: Birds fly for a variety of reasons, including migration,
hunting, and courtship. Aircraft, on the other hand, are designed
primarily for transportation, whether of people, goods, or military
personnel and equipment.
5. Environmental impact: Birds have a relatively low impact on the
environment, as they use renewable energy sources and emit no

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pollutants. Aircraft, however, require large amounts of fuel and emit
significant amounts of greenhouse gases, contributing to global
climate change.
In conclusion, while birds and aircraft both have the ability to fly, they do
so in very different ways, with different capabilities, and for different
purposes.
Q9) Biology as a science of life? Explain.
A9) Biology is indeed considered the science of life. It is the study of all
living things, including their physical and chemical processes, interactions
with each other and with their environment, and their evolution and
diversity.
Biology seeks to understand the underlying mechanisms that govern the
behavior of living things. For example, it explores the structure and
function of cells and tissues, the genetics of inheritance and evolution, the
behavior and ecology of organisms, and the interactions between
organisms and their environment.
Biology also encompasses many subdisciplines, such as anatomy,
physiology, ecology, genetics, and microbiology, each of which contributes
to our understanding of different aspects of life.
One of the defining characteristics of life is that living things are able to
maintain a complex internal organization and to respond to changes in
their environment. Biology seeks to understand the mechanisms that allow
living things to maintain this organization and to adapt to changes in their
environment.
Biology has many practical applications, including in medicine, agriculture,
and biotechnology. For example, our understanding of genetics has led to
advances in genetic engineering and the development of new treatments
for genetic diseases. Our understanding of ecology has helped us to better
manage and protect our natural resources.

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In conclusion, biology is indeed the science of life, exploring the diversity,
structure, function, evolution, and interactions of living things and their
environment.
Q10) Explain the Watson and Crick model?
A10) The Watson and Crick model refers to the discovery of the structure
of the DNA molecule by James Watson and Francis Crick in 1953. DNA
(deoxyribonucleic acid) is a molecule that contains the genetic information
that is passed from one generation of organisms to the next.
Watson and Crick's model showed that DNA is a double helix, meaning that
it consists of two chains of nucleotides that are coiled around each other
like a twisted ladder. The nucleotides in DNA consist of a sugar molecule, a
phosphate group, and a nitrogenous base. The nitrogenous bases in the
two chains are paired in a specific way, with adenine (A) always pairing
with thymine (T), and cytosine (C) always pairing with guanine (G).
The specific arrangement of the nitrogenous bases in the DNA molecule
determines the genetic information that is stored within it. This
information can be read and used by the cell to produce proteins, which
are the building blocks of life.
Watson and Crick's discovery of the structure of DNA was a major
milestone in the field of molecular biology, as it provided a physical
explanation for how genetic information could be stored and transmitted
from one generation to the next. Their work also paved the way for further
research into the molecular basis of genetics and the role of DNA in the
regulation of cellular processes.
Overall, the Watson and Crick model of the structure of DNA is considered
one of the most important scientific discoveries of the 20th century, as it
provided a foundation for our understanding of genetics and the molecular
basis of life.

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Unit-2
Q2) Explain the hierarchy of biological classification?
A2) The hierarchy of biological classification is a system used to organize
and categorize living organisms based on their evolutionary relationships. It
consists of several levels, each of which groups organisms into increasingly
larger and more inclusive categories. The hierarchy of biological
classification is typically presented as follows:
1. Species: A species is the most basic and fundamental unit of
classification. It is a group of organisms that are capable of
interbreeding and producing fertile offspring.
2. Genus: A genus is a group of related species. For example, the genus
Canis includes the species Canis lupus (wolf), Canis latrans (coyote),
and Canis familiaris (domestic dog).
3. Family: A family is a group of related genera. For example, the family
Canidae includes the genus Canis as well as the genera Lycaon (African
wild dog) and Vulpes (fox).

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4. Order: An order is a group of related families. For example, the order
Carnivora includes the family Canidae as well as the families Felidae
(cats) and Ursidae (bears).
5. Class: A class is a group of related orders. For example, the class
Mammalia includes the order Carnivora as well as the orders Primates
(primates), Rodentia (rodents), and Cetacea (whales and dolphins).
6. Phylum: A phylum is a group of related classes. For example, the
phylum Chordata includes the class Mammalia as well as the classes
Aves (birds), Reptilia (reptiles), and Amphibia (amphibians).
7. Kingdom: A kingdom is the highest level of classification, and includes
all living organisms. The traditional classification system recognizes
five kingdoms: Monera (prokaryotes), Protista (single-celled
eukaryotes), Fungi, Plantae (plants), and Animalia (animals).
This hierarchical system of classification is based on evolutionary
relationships, with each higher level grouping together organisms that
share a common ancestry. By organizing organisms into categories based
on their relationships, biologists can better understand the evolutionary
history of life on Earth and the relationships between different species.
Q3) Explain unicellular and multicellular organisms?
A3) A unicellular organism is an organism that possess a single cell. This
means all life processes or activities, such as reproduction, digestion,
feeding and excretion, occur in one single cell. Amoebas, bacteria, and
plankton are just some types of unicellular organisms. They are typically
microscopic and cannot be seen with the naked eye. Although much
smaller, unicellular organisms can perform some of the same complex
activities similar to multicellular organisms. Many unicellular organisms can
live in extreme environments, such as hot springs, thermal ocean vents,
polar ice, and frozen tundra. These unicellular organisms are collectively
called extremophiles. Extremophiles are resistant to extremes of
temperature or pH, and are specially adapted to live in places where
multicellular organisms cannot survive. This unique feature allows

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scientists to use unicellular organisms in many ways previously only
imagined. However, not all unicellular organisms are extremophiles. Many
other unicellular organisms live under the same narrow range of living
conditions as multicellular organisms, but still produce things necessary to
all life forms on Earth.
Multicellular organism, are organism composed of many cells, which vary
in degrees that are integrated and independent. The development of
multicellular organisms is followed by division of labour and cellular
specialization; cells become efficient in one process and are dependent
upon other cells for the necessities of life and survival.
A tissue, organ or organism that is made up of many cells is known as
multicellular. Humans, Animals, plants, and fungi are multicellular
organisms in nature and often, there is specialization of different cells for
various functions. Multicellular organisms assign biological responsibilities
such as barrier function, circulation, digestion, respiration and sexual
reproduction to specific organ systems such as the skin, heart, stomach,
lungs, and sex organs. These organs are composed of many different cells
and cell types that work together to perform specific tasks.
Q5) How are Autotrophs different from lithotrophs?
A5) Autotrophs: Autotrophs are organisms that can prepare their own
food, using materials from inorganic sources. The word “autotroph” is
derived from the root words “auto” for “self” and “troph” for “food.” An
autotroph is an organism that prepares its own food, without depending
on other organisms.
Autotrophs are extremely important and, in the absence of these
Autotrophs, no other forms of life can exist. Without plants that create
sugars from carbon dioxide gas and sunlight through the process
called photosynthesis.
Autotrophs are often called “producers.” They form the base of
an ecosystem’s energy pyramid, and provide the food for all the

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heterotrophs (organisms that must get their food from others) need to
exist.
Autotrophs more rarely, obtain chemical energy through oxidation
(chemoautotrophs) to make organic substances from inorganic ones.
Autotrophs do not consume other organisms; they are, however,
consumed by heterotrophs.
Lithotrophs
An organism that obtains its energy from inorganic compounds (such as
ammonia) through electron transfer, lithotroph is derived from (Greek
word lithos, meaning “stone”), is the ability of organisms to obtain energy
by the transfer of electrons from hydrogen gas to inorganic acceptors. It
has been proposed that the earliest forms of life on Earth used
lithotrophic metabolism and that photosynthesis was a process was later
identified.
Q10) Define Extremophiles?
A10) Many unicellular organisms can live in extreme environments, such as
hot springs, thermal ocean vents, polar ice, and frozen tundra. These
unicellular organisms are collectively called extremophiles. Extremophiles
are resistant to extremes of temperature or pH, and are specially adapted
to live in places where multicellular organisms cannot survive. This unique
feature allows scientists to use unicellular organisms in many ways
previously only imagined. However, not all unicellular organisms are
extremophiles. Many other unicellular organisms live under the same
narrow range of living conditions as multicellular organisms, but still
produce things necessary to all life forms on Earth.
Unit-3
Q3) Define Gene Mapping and Gene Interaction?
A3) Gene mapping refers to one of the two different ways of positioning
the gene on a chromosome. The first type of gene mapping was also called
genetic mapping. Genetic mapping determines how two genes on a

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chromosome relate in their positions, with the use of linkage
analysis. Physical mapping, which is the other type of gene mapping,
locates genes by their absolute positions on a chromosome using any
available technique. Once a gene is located, its DNA sequence determined,
it can be cloned and its molecular product studied.
Gene Interaction
Gene interactions can result in the suppression or alteration of a
phenotype. This occurs when an organism inherits two different dominant
genes, for example, resulting in incomplete dominance. This is commonly
seen in flowers, where breeding two flowers that pass down dominant
genes can result in a flower of an unusual colour caused by incomplete
dominance. If red and white are dominant, for example, the offspring
might be pinkish or striped in colour as the result of a gene interaction.
Q4) Explain the concept of Law of Independent and Law of segregation?
A4) The Law of Independent Assortment and the Law of Segregation are
two important principles in genetics that describe the behavior of genes
during the formation of gametes (sperm and egg cells).
The Law of Segregation
states that each individual
organism has two copies of
each gene, one from each
parent, and that during the
formation of gametes, each
gene segregates so that
only one copy goes into
each gamete. This means
that each gamete will
receive one and only one
copy of each gene. For
example, if an organism has
two copies of the gene for eye color, one blue and one brown, during the

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formation of gametes, each gamete will receive either the blue or the
brown gene, but not both.
The Law of Independent Assortment states that each pair of genes
segregates independently of each other during the formation of gametes.
This means that the segregation of one gene does not affect the
segregation of another gene. For example, the segregation of the gene for
eye color does not affect the segregation of the gene for hair color.
These two laws were first described by Gregor Mendel, the father of
modern genetics, through his studies of pea plants. The laws of
independent assortment and segregation form the basis of our
understanding of the inheritance of genetic traits, and they continue to be
important concepts in modern genetics.
Q5) Define Mitosis and Meiosis?
A5) Mitosis is the process that occurs when somatic cell divides to form
two daughter cells. It is an important process in normal organism
development, Mitosis requires a set of specialized cell

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structures. Chromosomes are the most important part for mitosis because
they are separated during the process and evenly distributed into two
daughter cells. The spindle is formed around a cytosolic structure called
centrosome, which is main driving force for chromosome separation.
Meiosis is the type of cell division by which germ cells (eggs and sperm) are
produced. Meiosis involves a reduction in the amount of genetic material,
during meiosis, chromosomes are also duplicated, cell division occurs twice
consecutively, leading the half of the chromosome number in 4 daughter
cells. This process is used for generating germ line cells, the gametes.
Fig: Mitosis is the process that occurs when somatic cell divides to form
two daughter cells and During meiosis, chromosomes are also duplicated,
cell division occurs twice consecutively, leading the half of the
chromosome number in 4 daughter cells
Q7) Explain the single Gene disorders in humans?
A7) When a certain gene is found to cause a disease, we refer to it as a
single gene disorder or a Mendelian disorder. In fact, single gene disorders
are not very common. For example, only one in 2,500 people are born with
cystic fibrosis. There are a number of inheritance patterns of single gene
disorders that are predictable it is figured out.
There are more than 4,000 human diseases caused by single mutated
genes that can be passed on to subsequent generations in either a

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dominant or recessive manner. Both egg and sperm providers may
unknowingly be carriers of a single gene disorder, which makes it crucial to
screen both partners.
Some examples of single-gene disorders include
1. Cystic fibrosis,
2. Alpha- and beta-thalassemia’s,
3. Fragile X syndrome
4. Marfan syndrome
5. Sickle cell Anaemia
6. Huntington's disease, and
7. Hemochromatosis.
Q10) Explain the concept of matching Phenotype to genes?
Ans. The mapping of a set of genotypes to a set of phenotypes is
sometimes referred to as the genotype–phenotype an organism's genotype
has a great influence (the largest by far for morphology) in the formation of
its phenotype, but this is not the only case. Even two organisms with
identical genotypes show differences in their phenotypes. One of the
experiences in everyday life with identical twins (monozygous). Identical
twins share the same genotype, since their genomes are identical; but they
show the same phenotype, although their phenotypes may look similar.
This is apparent that their mothers and close friends can spot minute
differences, even though others might not be able to see the subtle
differences. Further, identical twins can be distinguished by
their fingerprints, which are never completely identical.
Q5) Explain the differences between DNA and RNA?
A5)
Comparison DNA RNA
Full Name Deoxyribonucleic Acid Ribonucleic Acid
Function DNA replicates and stores
genetic information. The
RNA converts the genetic
information contained

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special feature is it is the
blueprint for all genetic
information contained within
an organism
within DNA to a format
used to build proteins, and
then moves it to ribosomal
protein factories.
Structure DNA consists is double
stranded, arranged in a double
helix. These strands are made
up of subunits called
nucleotides. Each nucleotide
contains a phosphate, a
nitrogenous base and a 5-
carbon sugar molecule.
RNA only is single stranded,
but like DNA, strand is
made up of nucleotides.
RNA strands are shorter
than DNA strands. RNA
sometimes forms a
secondary double helix
structure, but only
occasionally.
Length DNA is a much longer polymer
than RNA. A chromosome, for
example, is a single, long DNA
molecule, when opened would
be several centimetres in
length.
RNA molecules vary in
length, but are found to be
much shorter than long
DNA polymers. A large RNA
molecule may be a
thousand base pairs in
length.
Sugar The sugar in DNA is
deoxyribose, which contains
one less hydroxyl group than
RNA’s ribose.
RNA contains ribose sugar
molecules, without the
hydroxyl modifications of
deoxyribose.
Bases The bases in DNA are Adenine
(‘A’), Thymine (‘T’), Guanine
(‘G’) and Cytosine (‘C’).
RNA shares Adenine (‘A’),
Guanine (‘G’) and Cytosine
(‘C’) with DNA, but contains
Uracil (‘U’) rather than

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Thymine.
Location DNA is found in the nucleus,
with a small amount of DNA
also present in mitochondria.
RNA forms in the nucleolus,
and then moves to
specialised regions of the
cytoplasm depending on
the type of RNA formed.
Reactivity Due to its deoxyribose sugar,
which contains one less
oxygen-containing hydroxyl
group, DNA is a more stable
molecule than RNA, which is
useful for a molecule which
has the task of keeping genetic
information safe.
RNA, containing a ribose
sugar, is more reactive than
DNA and performs
enormous tasks but is not
stable in alkaline
conditions. RNA’s larger
helical grooves mean it is
more easily affected by the
attack of enzymes.
Ultraviolet
(UV)
Sensitivity
DNA is vulnerable to damage
by ultraviolet light.
RNA is more resistant to
damage from UV light than
DNA.
Q7) How are amino acids different from proteins?
A7) Amino acids are organic compounds in nature and combine to form
proteins molecules. Amino acids and proteins are the building blocks of all
lifeforms. When proteins are broken down or digested, amino acids are
left. Compared to any other class of macromolecules, Proteins are among
the most abundant organic molecules in living systems and are way more
diverse in structure and function. A single cell can contain thousands of
proteins, each having a unique function. All proteins are made up of one or
more chains of Amino acids although their structures, like their functions.

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Proteins can play a wide array of roles in a cell or organism. The common
protein is important in the biology of many organisms (including
humans). Proteins come in many different shapes and sizes. Some are
globular (roughly spherical) in shape, whereas others form long, thin fibers.
For example, the haemoglobin protein that carries oxygen in the blood is a
globular protein, while collagen, found in the skin, is a fibrous protein.
Amino acids are the monomers that make up proteins. Specifically, a
protein is made up of one or more linear chains of amino acids, each of
which is called a polypeptide. There are 20 different types of amino
acids present in proteins
Amino acids share a basic structure, which consists of a central carbon
atom, also known as the alpha (α) carbon, bonded to an amino group (NH2)
a carboxyl group {COOH}and a hydrogen atom.
Basic structure of an amino acid, every amino acid also has another atom
or group of atoms bonded to the central atom, known as the R group,
which determines the identity of the amino acid. For instance, if the R
group is a hydrogen atom, then the amino acid is glycine etc.
Q8) Write a short note on Cellulose?
A8) Cellulose a complex carbohydrate, or polysaccharide, consisting of
3,000 or more glucose units. They form the basic structural component of
plant cell walls; cellulose comprises about 33 percent of all
vegetable matter and is the most abundant naturally occurring

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organic compounds. Cellulose cannot be digested by man, cellulose is a
source of food for herbivorous animals (e.g., cows, horses) because they
retain it long enough for digestion by microorganisms present in the
alimentary tract; protozoans in the gut of insects such as termites also
digest cellulose. It has great economic importance, cellulose is processed to
produce papers and fibres and is chemically modified to yield substances
used in the manufacture of such items as plastics, photographic films,
and rayon. Other cellulose derivatives are used as thickening agents for
foods adhesives, explosives, and in moisture-proof coatings.
Q9) Define Denaturation?
A9) A protein’s shape is critical to its function, and, many different types of
chemical bonds may be important in maintaining this shape. Changes in
temperature and pH, as well as the presence of certain chemicals, may
disrupt a protein’s shape and cause it to lose functionality, a process
known as denaturation.
Denaturation is a process in which proteins or nucleic acids lose the
quaternary structure, tertiary structure, and secondary structure which is
present in their native state, by application of some external stress or
compound such as a strong acid or base, a concentrated inorganic salt, an
organic solvent (e.g., alcohol or chloroform), radiation or
heat. Since denaturation reactions are not strong enough to break the
peptide bonds, the primary structure (sequence of amino acids) remains
the same after a denaturation process. Denaturation disrupts the normal
alpha-helix and beta sheets in a protein and uncoils it into a random shape.
Q10) Short notes on starch?
A10) Starch, is a granular, white, organic chemical that is produced by all
green plants. Starch is a soft, white, tasteless powder that is insoluble in
alcohol, cold water, or other solvents. The basic chemical formula of the
starch molecule is (C6H10O5)n. Starch is a polysaccharide comprising of
glucosemonomers that are joined in α 1,4 linkages. The simplest form of
starch is the linear polymer amylose; amylopectin is the branched form.

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Starch is manufactured in the green leaves of plants from the excess
glucose produced during process of photosynthesis and serves as a reserve
food supply for the plant. Starch is stored in chloroplasts of the cell in the
form of granules and in others as storage organs in the roots of the cassava
plant; the tuber of the potato; the seeds of corn, wheat, and rice and
the stem pith of sago. According to the requirement, starch is broken
down, in the presence of certain enzymes and water, into its constituent
monomer glucose units, which diffuse from the cell to nourish the plant
tissues. In humans and other animals, starch from plants is broken down
into its constituent sugar molecules, which then supply energy to the
tissues.
Q2) How are Enzyme catalyzed reactions monitored?
A2) Monitoring the rate of an enzyme- that catalyses a reaction is called
‘enzyme kinetics’. The kinetics of an enzyme-catalysed reaction can
indirectly provide information about the mechanism of catalysis. The rate
or velocity of a reaction is the change in the concentration of reactant or
product per unit of time
 The rate of enzyme reaction is measured by the amount of substrate
changed or amount of product formed during a period of time.
 The rate is determined by measuring the slope of the tangent to the
curve in the initial stage of the reaction. The steeper the slope, the
greater is the rate.
 If enzyme activity is measured over a period of time, the rate of
reaction usually falls, most commonly as a result of a fall in the
substrate concentration.
 The rate of reaction is proportional to the enzyme concentration
provided that the substrate concentration at high level.
 If the enzyme concentration is increases, the rate of reaction
increases.

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For a give enzyme concentration, the rate of reaction increases with
increase in substrate concentration until all the available active sites are
occupied by the substrates.
Once all the active sites are used up, the rate of reaction remains constant
with increase in substrate concentration. Therefore, the theoretical
maximum rate is never quite obtained. The extra substrate has to wait until
the next enzyme/substrate complex release product before it takes part in
another reaction.
 Under constant other factor, pH affects the rate of reactions.
 Is Optimum pH being the pH at which the rate of enzyme-
controlled reaction is maximum pH which is different for different
enzymes.
 Rate of reaction decreases when the pH is either increased or
decreased from its optimum value. The ionic charge of acidic or basic
groups are altered with change in ph. And therefore disrupt the ionic
bonding that helps to maintain specific shape of enzyme
 Thus, change in pH leads to alteration of enzyme shape including the
active site.
 If extreme pH is introduced then it will denature the enzymes.

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The rate of enzyme activity is maximum, at optimum ph.
Q4) Explain the Lock and key mechanism of enzyme action?
A4) The lock-and-key analogy sees this process as very specific, further only
a particular key can fit into the keyhole of the specific lock. If the key is in
any way smaller, larger or simply a different shape, then it does not fit into
the keyhole, and subsequently a reaction cannot take place. The theory
was first described by Emile Fischer (lock-and-key analogy) in 1894, and
since then many other theories to were discovered explain the mechanics
of enzyme reactions.
The substrate binds to the active site, and a reaction takes place that
ultimately causes the release of the formed product. Enzymes catalyse this
reaction by facilitating chemical bond changes in the substrate through
altering the distribution of electrons.
Q6) Factors that influence Enzyme activity?
A6) The rate at which an enzyme works is influenced by many important
factors, e.g.,
The concentration of substrate molecules-
(When their availability is more, the quicker the enzyme molecules collide
and bind with them). The concentration of substrate is designated [S] and
is expressed in units of molarity.
The temperature-

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As the temperature rises, molecular motion also increases — and therefore
collisions between enzyme and substrate — speed up. But as enzymes are
proteins, there is an upper limit beyond which the enzyme
becomes denatured and ineffective high temperatures can denature
proteins.
The presence of inhibitors.
 Competitive inhibitors are molecules that bind to the same site as the
substrate — preventing the substrate from binding to the enzyme
active site — but are not changed by the enzyme.
 Non-competitive inhibitors are molecules that bind to some other site
on the enzyme reducing the power of the catalysis.
PH.
PH influences the conformation of a protein and as enzyme activity is
crucially dependent on protein conformation, its activity is affected
accordingly.
Q8) Explain the difference between Catalyst and an Enzyme?
A8) Catalyst and enzyme are two substances that increase the rate of a
reaction without being changed by the reaction. There are two types of
catalysts as enzymes and inorganic catalysts. Enzymes are a type of
biological catalysts. The main difference between catalyst and enzyme is
that catalyst is a substance that increases the rate of a chemical reaction
whereas enzyme is a globular protein that can increase the rate of
biochemical reactions. The inorganic catalysts include mineral ions or
small molecules. In contrast, enzymes are complex macromolecules with
3D structures. Enzymes are specific and work in mild conditions.
Catalyst Enzyme
Catalyst defined as the molecules that
speed up the
Rate of a reaction without having a
change in its structure.
An enzyme is known as a
Biological catalyst and
Globular protein that
Speed up natural reactions.
Correlation

23. 23
Could either be enzymes or inorganic
salts
Considered as a type of a
Catalyst
Type
Mineral ions or small molecules Globular proteins
Size Difference
Similar in size to the molecule of
substrate
Very larger as compared to
The substrate molecule
Molecular Weight
The molecular weight is low The molecular weight of
Enzymes are high
Action
Normally act on physical reactions Always act on biochemical
Reactions
Efficiency
Work less efficiently Work highly efficiently
Specificity
Can maximize the rate of various set of
reactions
Can only act and increase
The rate of a particular
Reaction
Regulator Molecules
Cannot control the function of inorganic
catalysts
Can regregulate the function of
enzymes by
Binding bindingof
regulatory molecules with the
Specific enzyme
Temperature
Not sensitive to small temperature
changes, so they
Work at high temperatures
Temperature specific, so at
Low temperature, enzymes
Become inactive, and at high
Temperature, enzymes Get
denatured

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PH
Not usually sensitive to small changes
occurring in pH
Sensitive to small pH changes
and
Operate only at a specific range
of
PH
Pressure
Work only at high pressure Work only at normal pressure
Protein Poisons
Protein poisons contain no effect Can be affected and poisoned by
Protein poisons
Short Wave Radiations
Contain no effect on the inorganic
catalysts
Can have denatured the
enzymes
Examples
Iron, platinum, and vanadium oxide Glucose-6-phosphate, alcohol
Dehydrogenase, amylase, lipase,
And aminotransferase