Chemistry Model Questions Test # 1 X Chapter # 4 Biochemistry
Short Questions
Q1. Write chemical names & deficiency disease arises due to of following Vitamins:
(i) Vitamin A
(ii) Vitamin D
(iii) Vitamin E
(iv) Vitamin K
(v) Vitamin C
Q2. Define the following terms:
Peptide linkage, saponification, lipids, biochemistry, enzymes, fats and oils, Proteins, amino acids.
Q3. Differentiate between
(i) Dextrorotary and Levorotatory Sugars
(ii) fats and oils.
(iii) fat and water soluble vitamins.
Q4. Enumerate the important uses of carbohydrates.
Q5.
How do plants synthesize
carbohydrates? Give equation of preparation.
Q6. What are Oligosaccharides and
Disaccharides. Give their examples and sources.
Q7. What are polysaccharides? Give their
examples. How monosaccharides are produced from polysaccharides?
Q5. What are proteins? Give their importance
and sources.
Q6.What is peptide bond? How it is formed?
Also explain dipeptides and tripeptides.
Q10. What
are amino acids and give their general structure? How many Essential and
Non-essential Amino acids are
there?
Q11. What are fatty acids? Give their examples
and chemical nature.
Q12. Explain Hydrogenation of vegetable oil into vegetable ghee.
Q13. What is vitamin D? Give its sources and
importance.
Q14. Write down importance of deoxyribonucleic
acid (DNA).
Q15. Write down the range of Number of Amino acids and molecular weights of Proteins
Q16.What are nucleic acids? Give their
importance of Nucleic Acid
Q17. Describe the sources and uses of vitamin A.
Q18. Justify that water soluble vitamins are not
injurious to health.
Detailed Questions
Q1. What are the carbohydrates? Explain
sources and uses of carbohydrates.
Q2. What are lipids? Write down the sources
and uses of lipids.
Q3. Describe vitamins and types of vitamins.
Q4. Describe in detail nucleic acids, RNA and
DNA.
Q5. How you can justify that deficiency of
different types of vitamins causes diseases in human beings?
Answers of Chemistry Model Questions Test # 1 X Chapter # 4 Biochemistry
Short Questions
Q1. Write
chemical names & deficiency disease arises due to of following Vitamins:
Answer
(i) Deficiency disease of Vitamin A ……Night blindness, Xerophthalima, dryness of skin
(ii) Deficiency disease of Vitamin D ………Rickets
(iii) Deficiency disease of Vitamin E …… Sterility, haemolysis
(iv) Deficiency disease of Vitamin K ……Haemorrhage
(v) Deficiency disease of Vitamin C …… Scurvy
Q2. Define the following terms:
Peptide linkage, saponification, lipids, biochemistry, enzymes, fats and oils, Proteins, amino acids.
Answer
Peptide linkage
A peptide
linkage is an acid-amide bond formed between amino acids by the elimination of
water. Due to this linkage protein is formed.
saponification
The alkaline hydrolysis of fats or oils with alkali like NaOH or KOH to
give salt of fatty acid called soap and glycerine is called saponification.
lipids
Lipids are a group of naturally occurring
heterogeneous organic compounds which includes fats, oils, waxes, and are
insoluble in water but easily soluble in Bloor’s reagent (mixture of diethyl
ether and ethyl alcohol in the ratio of 2:1) and organic solvents like ether,
benzene, acetone, carbon tetrachloride and chloroform.
biochemistry
The branch of chemistry which
deals with the study of chemical substances and processes that occur in living
organisms (plants and animals) is known as biochemistry.
enzymes
Enzymes are the class of proteins which
are the complex polymeric nitrogenous organic biocatalysts produced by living
cells that catalyze all types of biochemical reactions in the living organisms.
fats and oils
Oils and fats are triesters of long chain carboxylic
(fatty) acids with glycerol. These esters are made of three fatty acids,
therefore, they are called triglycerides or triesters. General formula of
triglycerides is as under.
Proteins
Proteins are highly complicated macromolecular
nitrogenous organic compounds made up of amino acids found in all the cells of
living organisms. Proteins are polymers or macro-molecules of simple units
called monomers of amino acids which are linked with each other through peptide
Linkage. All proteins yield amino acids upon hydrolysis
amino acids.
Amino acids are building blocks of protein. They are
bi-functional organic compound containing an acidic carboxyl (–COOH) and a
basic amino (–NH2) groups.
Q3. Differentiate
between
Answer
Dextrorotary and Levorotatory Sugars
(ii) fats and oils.
(iii) fat and water
soluble vitamins
Q4. Enumerate
the important uses of carbohydrates.
Answer
Uses
of Carbohydrates
1. They are main energy providing materials or energy source for the
survival of both plants and animals. (Our body uses carbohydrates in the form of glucose.
Glucose is the only form of carbohydrates that is used directly by muscles for
energy. It is important to note that brain needs glucose as an energy source,
because it cannot use fat for this purpose).
2. They sustain plant structure.
3. Carbohydrates, in the form of starch in
plants and glucose in mammals, serve as energy storage.
4. They regulate our blood sugar levels. Low sugar level in body results in hypoglycemia.
(Insulin is hormone which enables our body to use glucose obtained from food or
glycogen (stored food). If body lack insulin, the glucose level will rise in
blood which leads to the diabetes).
5. Sucrose
is a food additive. It's found in confectioneries,
condensed milk, canned fruits, jams, and jellies, among other things.
6. Carbohydrate fiber helps in cholesterol
reduction and blood pressure regulation.
7. Carbohydrates coexist with a variety of
proteins and lipids in bio systems.
8. Celluloses provide food its bulk and
fibre. It promotes peristalsis in the intestine. Cellulose
is used as a raw material in a variety of industries, including textiles and
paper.
10. Starch is used to improve the writing
characteristics of paper by coating and sizing it. Starch is utilized in the
production of ethanol and in laundries.
Q5. How
do plants synthesize carbohydrates? Give equation of preparation.
Answer
Synthesis
of Carbohydrates (glucose) by Plants through Photosynthesis
Carbohydrate
like glucose is synthesized by plants through photosynthesis process from
carbon dioxide and water in the presence of sunlight and green pigment
chlorophyll (catalyst). The glucose is further polymerized to form starch and
cellulose.
Q6. What
are Oligosaccharides and Disaccharides. Give their examples and sources.
Answer
Definition
of Oligosaccharides (Greek; Oligo = few)
Oligosaccharides give 2 to 10 (9) units of
monosaccharides on hydrolysis. In oligosaccharides, monosaccharides are linked
with each other by glycosidic bond or linkage.
Disaccharides
Disaccharides
are those oligosaccharides which contain two monosaccharides. The most
important oligosaccharides are disaccharides like sucrose. On hydrolysis,
sucrose produces one unit of glucose and one unit of fructose.
Examples
Sucrose, maltose, lactose (milk sugar) are important
members of disaccharides.
Sources
Sucrose; Sugarcane,
sugar beet, beet root, carrots, maple, pineapple etc.
Lactose Milk
Maltose ; Wheat (گندم)
, barley (جو) etc.
Raffinose Legumes
(phaliyanپھلیاں ،)
Q7. What
are polysaccharides? Give their examples. How monosaccharides are produced from
polysaccharides?
Answer
Polysaccharides
are macromolecular carbohydrates also called polymeric carbohydrates giving
more than 10 monosaccharides on hydrolysis consisting of hundreds to thousands
of monosaccharides linked by glycosidic linkage.
Examples
of polysaccharides
1.cellulose, starch (plant origin), glycogen (animal origin), amylose etc. are common polysaccharides.
Cellulose
is found in the cell walls, wood, linen, paper, cotton etc. Cotton contains 95%
cellulose.
2. Starch occurs in cereals like wheat,
rice, barley etc. and roots of potatoes.
3. Glycogen is also called animal
starch found in muscles and liver of animals
Q8. What
are proteins? Give their importance and sources.
Answer
Definition
of Proteins
The
word protein is taken from Greek ‘Proteios’ means ‘first’.
Proteins
are highly complicated macromolecular nitrogenous organic compounds made
up of amino acids found in all the cells of living organisms. Proteins
are polymers or macro-molecules of
simple units called monomers of amino acids which are linked with each other
through peptide Linkage. All proteins yield amino acids upon hydrolysis
Function
They
have central position in architecture and functioning of living matter.
Sources
and Uses of Proteins
Proteins
make up more than 50% of the dry weight of animals. Each protein has its
source and carries out a specific function. The important sources of proteins
are eggs, pulses, nuts, edible seeds, beans, peas, chees etc. Sources and uses
of protein are as follows:
1. Sources of
animal’s proteins are meat, mutton, poultry or chicken, fish, eggs. These are
used as food by human beings as they are essential for the formation of
protoplasm.
2. Enzymes
are proteins that are produced by the living cells. They catalyze the chemical
reactions taking place in the bodies. They are highly specific and have
extraordinary efficiency. Many enzymes are used as drugs in pharmaceuticals.
They control the bleeding and treat blood cancer.
3. Hides are
proteins. These are used to make leather by tanning. Leather is used to make
shoes, jackets, coats, sports items, equipment’s etc.
4. Proteins
are found in bones. When bones are heated they give gelatin. Gelatin is used to
make bakery items.
5. Plants
also synthesize proteins, such as pulses, beans and other legumes etc. These
are used as food.
Q9. What
is peptide bond? How it is formed? Also explain dipeptides and tripeptides.
Answer
A peptide linkage is an acid-amide bond
formed between amino acids by the elimination of water. Due to this linkage
protein is formed. When thousands of amino acids polymerize they form protein.
A protein molecule formed with two amino acids is termed as dipeptide, with
three tripeptide and so on.
Q10. What are amino acids and give their general structure? How
many Essential and Non-essential Amino acids
are there?
Answer
Amino
acids are building blocks of protein. They are bi-functional organic
compound containing an acidic carboxyl (–COOH) and a basic amino
(–NH2) groups.
Where
‘R’ is Side chain which is different for different amino acids.
Essential
and Non-essential Amino acids
Up to
20 amino acids have been found in nature, ten are essential and remaining ten
are non-essential. Body can only synthesize non-essential ten amino acids.
Q11. What
are fatty acids? Give their examples and chemical nature.
Answer
Definition
of Fatty acids
Fatty
acids are building blocks of lipids. They are long chain saturated or
unsaturated carboxylic acids with a lengthy chain, either saturated or
unsaturated. Fatty acids form esters (oils or fats) and glycerol in the
presence of mineral acids.
Examples
of Fatty acids
1. Palmitic
acid; C15H31COOH
2. Stearic
acid; C17H35COOH
Chemical
Nature
Lipids
are macromolecules made up of fatty acids. Lipids include oils and fats. Oils
and fats are triesters of long chain carboxylic (fatty) acids with glycerol.
These esters are made of three fatty acids, therefore, they are called
triglycerides or triesters. General formula of triglycerides is as under.
Q12. Explain
Hydrogenation of vegetable oil into vegetable ghee.
Answer
Hydrogenation
of vegetable oil
Vegetable
oils are triester of glycerol and fatty acids of unsaturated long chains.
Vegetable oil is converted into saturated fat ghee by the chemical process
called hydrogenation. In this process unsaturated vegetable oil is treated with
molecular hydrogen (H2) in the presence of catalyst like nickel (ni) or palladium (Pd) at 250-300°C to
form vegetable ghee (fat). This is an addition reaction of oil with H2
to form an adduct called fat.
Q13. What
is vitamin D? Give its sources and importance.
Answer
Definition
Vitamin
D(Anthracitic vitamin) is a fat-soluble vitamin.
Sources.
Fish
liver, dairy products (milk, butter), mushrooms, oils and fats, Vitamin D is
formed in the skin when it is exposed to sunlight
Importance
Bones,
teeth (controls the metabolism of calcium and phosphorus in body. Its
deficiency leads to Rickets (softening and weakening of bones in children).
Q14. What
are nucleic acids? Write down importance of deoxyribonucleic acid (DNA).
Answer
Nucleic acids are biopolymers which are the macromolecules formed by the
polymerization of nucleotides (monomers). They contain elements like carbon, hydrogen,
oxygen, nitrogen and rarely phosphorus. They are generally long
chain molecules made up of nucleotides. Each nucleotide consists of three
components; nitrogenous base (purines and pyrimidines), a pentose sugar and a
phosphate group).
Importance
of Nucleic Acid
1. They are the most vital material for
cell functioning.
2. They are the storage of genetic
information.
3. They work for mutation to save the
cells and body form threatening diseases.
4. They transfer heredity characters
from one generation to another generation.
5. They serve as a source of energy in
the form of ATP.
Q15. Write
down the range of Number of Amino acids
and molecular weights of Proteins
Answer
Number
of Amino acids in Proteins
Proteins
may contain 60 to 6000 amino acids molecules.
molecule weight
of proteins
Generally
the molecule weight of proteins ranges from 43000-50,000,000 daltons (1
dalton = 1amu).
Q17. Describe the sources and uses of vitamin
A.
Answer
Sources
Butter, fish, eggs, milk, cheese
(Dairy products) etc. It can also be obtained from the beta-carotene found in
green and yellow vegetables, carrots and liver.
Uses
Important for Eyes (form visual
pigments) and skin. Its deficiency causes Night blindness (inability to see in
dim light), Xerophthalima (tear glands cease to function), dryness of skin etc.
eye inflammation
Q18. Justify that water soluble vitamins are
not injurious to health.
Answer
Water-soluble
vitamins are rapidly excreted from the body. Hence, these vitamins are not
toxic even if taken in large quantity. However, their deficiency causes
disease.
Detailed Questions
Q1. What
are the carbohydrates? Explain sources and types of carbohydrates.
Answer
Definition
Carbohydrates
are naturally occurring organic compound are important food factor.
Carbohydrates are macromolecules defined as polyhydroxy aldehydes or
polyhydroxy ketones or large molecules that give these compounds
on hydrolysis. They generally contain elements like carbon, hydrogen and
oxygen.
General
formula
They
have general formula Cn(H2O)n showing
that these compound contain hydrogen and oxygen in the ratio as in H2O
i.e. 2:1 (although they do not contain water molecules).
Classification
of carbohydrates based on hydrolysis
Carbohydrates
are classified as into three types based on hydrolysis:
1. Monosaccharides
2. Oligosaccharides
3. Polysaccharides
Monosaccharides
(Greek; Mono = one)
Definition
Monosaccharides
are the simplest sugars which cannot be further simplified on hydrolysis.
No of
Carbon atoms
They
consist of 3 to 10 (9) carbon atoms.
Properties
Monosaccharides
are white crystalline solids. They are soluble in water and have sweet taste.
They cannot be hydrolyzed. They are reducing in nature, therefore, these are
called reducing sugars.
Types
they are further classified according to the number of carbon atoms
in their molecules as trioses, tetroses, pentoses, hexoses, and so on.
The
important monosaccharides are hexoses like glucose and fructose, etc.
Glucose
1. Glucose
(grape sugar) belongs to aldoses and fructose (honey) to ketones are examples
of monosaccharides.
2. Glucose is
obtained naturally as dextrorotatory and is present in grapes (20-30%), honey.
It is also found in combined state in cane sugar, starch and cellulose.
3. Glucose is
a rapid source of energy for patients. Fructose (Latin; fructus = fruit) occurs
in ripe fruits, honey, cane sugar etc.
4. Glucose is
a necessary component of human blood, that is why it is also known as blood
sugar. The normal range for blood glucose is 65-110 mg (0.06-0.1%) per 100 mL.
Glucose
is a pentahydroxy aldehyde (aldo hexose) while fructose is pentahydroxy
ketone (keto hexose) having the open chain structures as follows and
general formula C6H12O6
Oligosaccharides
(Greek; Oligo = few)
Definition
Oligosaccharides give 2 to 10 (9) units of
monosaccharides on hydrolysis. In oligosaccharides, monosaccharides are linked
with each other by glycosidic bond or linkage.
Properties
Oligosaccharides
like monosaccharides are white, crystalline solids, sweet in taste and easily
soluble in water. (They may be reducing or non-reducing).
Types
they are classified as disaccharides, trisaccharides,
tetrasaccharides etc., depending upon the number of monosaccharides units they
produce on hydrolysis.
Disaccharides
Disaccharides
are those oligosaccharides which contain two monosaccharides. The most
important oligosaccharides are disaccharides like sucrose. On hydrolysis,
sucrose produces one unit of glucose and one unit of fructose.
Examples
Sucrose, maltose, lactose (milk sugar) are important
members of disaccharides.
Polysaccharides
Definition
Polysaccharides
are macromolecular carbohydrates also called polymeric carbohydrates giving
more than 10 monosaccharides on hydrolysis consisting of hundreds to thousands
of monosaccharides linked by glycosidic linkage.
Properties
Polysaccharides
are amorphous, tasteless and insoluble in water. They are non-reducing in
nature.
Examples
of polysaccharides
1. cellulose, starch (plant origin), glycogen (animal origin), amylose etc. are common polysaccharides.
Cellulose
is found in the cell walls, wood, linen, paper, cotton etc. Cotton contains 95%
cellulose.
2. Starch occurs in cereals like wheat,
rice, barley etc. and roots of potatoes.
3. Glycogen is also called animal
starch found in muscles and liver of animals
Q2. What
are lipids? Write down the sources and uses of lipids.
Answer
Definition
Lipids
are a group of naturally occurring heterogeneous organic compounds which
includes fats, oils, waxes, and are insoluble in water but easily soluble
in Bloor’s reagent (mixture of diethyl ether and ethyl alcohol in the ratio
of 2:1) and organic solvents like ether, benzene, acetone, carbon
tetrachloride and chloroform.
Constituent
Elements
Lipids
are generally composed of elements like carbon, hydrogen and oxygen but there
are some lipids which contain nitrogen and phosphorus too. Lipids are the building
blocks of cells.
Sources
of Lipids
Animals
Marine
animals like salmon and whales are rich sources of lipids. Butter, ghee, cheese
are obtained from animals.
Plants
Sun
flower, coconut, ground nuts, corn, cotton seed, olive etc. are important plant
sources of lipids.
Uses
of Lipids
1. They act as transporter of fatty
acids and fat soluble vitamins (A, D, E and K) in body.
2. Some lipids reduce cholesterol level
in body.
3. Fats and oils are used for cooking
and frying of food.
4. Fats and oils are used in
detergents, soaps, cosmetic, polishes and paints.
5. They activate the enzymes.
6. Animals fats are found in adipose
tissue cells. Animals secrete milk from which butter and ghee is obtained which
are used for cooking and frying
of food, for preparing bakery products and sweets.
Q3. Describe
vitamins and types of vitamins.
Answer
In
1912, Hopkins noticed that in addition to carbohydrates, proteins and fats
there are other nutrients needed for normal growth. Although these substances
were needed in small quantity, yet these substances were called Accessory
Growth Factors. Later Funk proposed the name Vitamin for these substances. He
discovered Vitamin B1 (Thiamin).
Types
of Vitamins on the Basis of Solubility
Vitamins
are divided into two types based on their solubility:
(i)
Water Soluble Vitamins
The
vitamins that dissolve in water are called water-soluble vitamins. They are
obtained from cereals and fruits. These vitamins are not stored in body.
These
vitamins are B complex (this include 10 vitamins) and vitamin C (ascorbic
acid). Water-soluble vitamins are rapidly excreted from the body. Hence, these
vitamins are not toxic even if taken in large quantity. However, their
deficiency causes disease.
(ii)
Fat Soluble Vitamins
The
vitamins which dissolve in fats and organic solvents are called fat soluble
vitamins. These are vitamin A, D (sunshine vitamin), E and K. They are stored
in the body for long period of time. These vitamins are obtained from lipids. If these vitamins are taken in large quantity,
they accumulate in the body and cause diseases.
For
example,
(i) Excess of vitamin A causes irritation
and headache
(ii) Vitamin D calcification (accumulation)
in the body causes bone-pain and bonelike deposits in the kidney.
(iii) Vitamin E excess causes fatigue and
headache
(iv) Excess vitamin K causes liver and
kidney diseases.
Sources,
uses and diseases due to
deficiency of some fat soluble vitamins.
Q4. Describe
in detail nucleic acids, RNA and DNA.
Answer
ribonucleic Acid (RNA)
It
consists of ribose sugar. It is a single stranded molecule. It is
responsible for putting the genetic information to work in the cell to build
proteins. Its role is like a messenger.
RNA is
synthesized by DNA to transmit the genetic information. RNA receives, reads,
decodes and uses the given information to synthesize new proteins. Thus RNA
is responsible for directing the synthesis of new proteins.
Deoxyribonucleic Acid (DNA)
DNA
consists of deoxyribose sugar. Its structure was discovered by J.
Watson and F. Crick in 1953. It is long two-chained double
stranded molecule consisting of two chains of considerable length.
Each
chain is made up of sugar, phosphate and a base. The sugar and phosphate
groups make the backbone of the chains and two chains are linked through bases.
The chains are wrapped around each other in a double helix form as shown in
figure
DNA is
the permanent storage place for genetic information in the nucleus of a cell.
It carries and stores all genetic information of the cell. It passes these
information as instructions from generation to generation how to synthesize
particular proteins from amino acids. These instructions are ‘genetic code of
life’. They determine whether an organism is a man or a tree or a donkey and
whether a cell is a nerve cell or a muscle cell.
The
sequence of nitrogenous bases in DNA determines the protein development in new
cells. The function of the double helix formation of DNA is to ensure that no
disorder takes place.
DNA
carries genes that controls the synthesis of RNA. Errors introduced into the
genes synthesize faulty RNA. It synthesizes faulty proteins that do not
function the way they are supposed to. This disorder causes genetic diseases.
Q5. How
you can justify that deficiency of different types of vitamins causes diseases
in human beings?
Answer
A balanced diet is extremely
important for the good health of a person. Insufficient intake of a particular vitamin
can lead to a deficiency disease in human beings.
List of Deficiency Diseases
Following is a list of major deficiency
diseases that occur due to lack of essential minerals and vitamins:
Deficiency of vitamin-A (Retinol)
causes Night blindness
Deficiency of vitamin-C (Ascorbic acid)
causes Scurvy
Deficiency of vitamin-D (Calciferol) causes
Rickets
Deficiency of vitamin-K (Phylloquinone)
causes Excessive bleeding due to injury
Deficiency of vitamin-E causes Sterility, haemolysis
Deficiency of vitamin-B1 (Thiamine) causes
Beri-beri
Deficiency of vitamin-B2 (Riboflavin) causes
Retarded growth, bad skin
Deficiency of vitamin-B12
(Cyanocobalamin) causes Anaemia
No comments:
Post a Comment