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Quiz 6
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Q.1
Most of hydrolytic reactions are ... ..... [ MPPMT 2001]
0%
a) Exothermic
0%
b) Endothermic
0%
c) Irreversible
0%
d) Reversible
Explanation
If a compound is represented by the formula AB in which A and B are atoms or groups and water is represented by the formula HOH, the hydrolysis reaction may be represented by the reversible chemical equation AB + HOH ⇋H + BOH Answer : (d)
Q.2
Amino acid present in histones are ... ... [ Odisha 2004]
0%
a) Arginine and histidine
0%
b) Arginine and lysine
0%
c) Lysine and histidine
0%
d) Arginine and cytosine
Explanation
Arginine and lysine are abundant amino acids found in basic proteins such as histones and protamines Answer : (b)
Q.3
The simplest amino acid is .... .... [ CBSE 2005 ]
0%
a) Glycine
0%
b) Lysine
0%
c) Tyrosine
0%
d) Aspartic acid
Explanation
The simplest, and smallest, amino acid found in proteins is glycine for which the R-group is a hydrogen (H). Answer : (a)
Q.4
Which is not pyrimidine .... .... [ MPPMT 2007]
0%
a) Guanine
0%
b) Thymine
0%
c) Uracil
0%
d) Cytosine
Explanation
guanine is a derivative of purine. pyrimidine derivatives are cytosine (C), thymine (T), and uracil (U). Answer : (a)
Q.5
Nicotinamide can be synthesised in human body from ... .... [ AIIMS 2002]
0%
a) Fructose
0%
b) Lactose
0%
c) Tyrosine
0%
d) Tryptophan
Explanation
Our body is able to convert tryptophan, an amino acid regularly found in the body, into niacin. Niacin is then converted to nicotinamide Answer : (b)
Q.6
Which one is made of a single ring of atoms? ... ...[ Pb PMT 1997]
0%
a) Guanine
0%
b) Adenine
0%
c) Thymine
0%
d) Glycine
Explanation
Pyrimidine nucleobases are simple ring molecules pyrimidine derivatives are cytosine (C), thymine (T), and uracil (U). Purine nucleobases are fused-ring molecules. Answer : (c)
Q.7
Glycosidic linkage at place of branching in starch and glycogen is ... ...
0%
a) α1 → 6
0%
b) α1 → 4
0%
c) β1 → 4
0%
d) β1 → 6
Explanation
Linkage α1 → 6 is side chain Answer : (a)
Q.8
Choose the correct statement ... .... [ Manipal 1997]
0%
a) DNA is hereditary material
0%
b) RNA is hereditary material
0%
c) DNA is hereditary material but where it is absent RNA can function as hereditary material
0%
d) Both DNA and RNA are hereditary materials
Explanation
Like DNA, RNA can carry genetic information. Answer : (c)
Q.9
Histones are present in ... .... [ MPPMT 2012]
0%
a) Cell membrane
0%
b) Lysosomes
0%
c) Nucleosomes
0%
d) Sphaerosomes
Explanation
Histones are highly basic proteins found in eukaryotic cell nuclei that pack and order the DNA into structural units called nucleosomes. Answer : (c)
Q.10
Which is not a nucleotide component? ... ... [ AFMC 1998]
0%
a) Thymine
0%
b) Guanine
0%
c) Lysine
0%
d) Adenine
Explanation
Lysine (symbol Lys or K) is an α-amino acid that is used in the biosynthesis of proteins. Each nucleotide consists of three components: a nitrogenous base: cytosine (C), guanine (G), adenine (A) or thymine (T) a five-carbon sugar molecule (deoxyribose in the case of DNA) a phosphate molecule. Answer : (c)
Q.11
Protein denaturation is caused by disruption of ... .. [ DPMT 2003 ]
0%
a) Peptide bonds
0%
b) Three-dimensional configuration
0%
c) Tertiary and secondary structure
0%
d) Both b and c
Explanation
Denaturation occurs because the bonding interactions responsible for the secondary structure (hydrogen bonds to amides) and tertiary structure are disrupted. Once its interaction is disrupted, it changes the three dimensional configuration and gets converted into single string of amino acids. Answer : (d)
Q.12
Which one is found only in RNA and not in DNA? ... ... [ AFMC 1996]
0%
a) Cytosine
0%
b) Adenine
0%
c) Uracil
0%
d) Guanine
Explanation
The bases adenine, guanine, and cytosine are found in both DNA and RNA; thymine is found only in DNA, and uracil is found only in RNA. Answer : (c)
Q.13
Allosteric modulation is due to inhibition of coenzyme action by ... .. [ kerala 2006]
0%
a) Competitive inhibition
0%
b) Substrate concentration
0%
c) Product of reaction
0%
d) Enzyme concentration
Explanation
Allosteric modulators are a group of substances that bind to a receptor to change that receptor's response to stimulus. Allosteric modulators can be positive (activating) causing an increase of the enzyme activity or negative (inhibiting) causing a decrease of the enzyme activity. Answer : (d)
Q.14
Silk is formed of ... .... [ MPPMT 2012]
0%
a) Fibroin
0%
b) Collagen
0%
c) Elastin
0%
d) Myosin
Explanation
Fibroin is an insoluble protein present in silk produced by numerous insects, such as the larvae of Bombyx mori, and other moth genera such as Antheraea, Cricula, Samia and Gonometa. Answer : (a)
Q.15
Enzymes exist in the cells as ... .... [ MPPMT 1993]
0%
a) Solid
0%
b) Crystals
0%
c) Solution
0%
d) Colloid
Explanation
The cytoplasm of living cells containing many types of biomolecular colloidal suspensions Answer : (d)
Q.16
Which is not a lipid? .... .. [ kerala 2000 ]
0%
a) Wax/lecithin
0%
b) Sterol/Cholesterol
0%
c) Glycerol/maltose
0%
d) Lecithin/Ghee
Explanation
Lipids are a class of macromolecules that are nonpolar and hydrophobic in nature. Major types include fats and oils, waxes, phospholipids, and steroids Maltose is a sugar made out of two glucose molecules bound together. The glycerol backbone is found in those lipids known as glycerides. Answer : (c)
Q.17
IAA and serotonin are formed from .... .... [ DPMT 2007]
0%
a) Tyrosine
0%
b) Tryptophan
0%
c) Phenylalanine
0%
d) Glycine
Explanation
Serotonin is made from the essential amino acid tryptophan. Tryptophan deficiency can lead to lower serotonin levels. This can result in mood disorders, such as anxiety or depression Answer : (b)
Q.18
Key and lock hypothesis of enzyme action was given by ... .... [ AIIMS 1996]
0%
a) Fischer
0%
b) Koshland
0%
c) Buchner
0%
d) Kuhne
Explanation
The specific action of an enzyme with a single substrate can be explained using a Lock and Key analogy first postulated in 1894 by Emil Fischer. Answer : (a)
Q.19
Match the column ... ... [ AIIMS 2012]
a)Alkaloids
i) Carotenoids, Anthocyanin
b)Pigments
ii) Vinblastine, Curcumin
c) Drugs
iii) Morphine, Codeine
0%
a) a - ii, b - iii, c - i
0%
b) a - i, b - iii, c - ii
0%
c) a - i, b - ii, c - iii
0%
d) a - iii, b - i, c - ii
Explanation
The six opium alkaloids which occur naturally in the largest amounts are morphine, narcotine, codeine, thebaine, papaverine and narceine. a - iii Carotenoids and anthocyanins are accessory pigments. b - i Vinblastine is an anti-cancer ("antineoplastic" or "cytotoxic") chemotherapy drug. Curcumin is known for its antiinflammatory and antioxidant properties c - ii Answer : (d)
Q.20
Template/lock and key theory of enzyme action is supported by .... .... [ BHU 1997]
0%
a) Enzymes speed up reaction
0%
b) Enzymes occur in living beings and speed up certain reactions
0%
c) Enzymes determine the direction of reaction
0%
d) Compounds similar to substrate inhibit enzyme activity
Explanation
Generally, the product, having a different conformation than substrate can no longer bind to the cognate cleft of active site and is hence released from the enzyme. Inhibitors of the enzyme usually mimics the substrate conformation and can easily bind to the enzyme active site (due to conformational compatibility) but cannot be acted upon by the active site amino acids, hence enzyme would be rendered inactive. Hence this supports the lock and key theory of enzyme substrate interaction. So, the correct answer is 'Compounds similar to substrate inhibit enzyme activit Answer : (d)
Q.21
Mathematical explanation for enzyme action on substrate was provided by ... ... [ kerala 2003 ]
0%
a) Vant Hoff
0%
b) Hans Krebs
0%
c) Michaelis and Menten
0%
d) Calvin
Explanation
The Michaelis-Menten model is based on the assumption that the enzyme binds the substrate to form an intermediate complex which then dissociates to form the final product and release the enzyme in its original form. Answer : (c)
Q.22
Which is distributed more widely in a cell? ... .. [ CBSE 1992]
0%
a) DNA
0%
b) RNA
0%
c) Chloroplasts
0%
d) Sphaerosomes
Explanation
RNA is more common and abundant than DNA Answer : (b)
Q.23
Activity of an enzyme is affected least by .... .... [ DPMT 2009]
0%
a) Temperature
0%
b) Concentration of substrate
0%
c) Concentration of enzyme
0%
d) Original activation energy of the system
Explanation
Enzymes allow many chemical reactions to occur within the homeostasis constraints of a living system. Enzymes function as organic catalysts. A catalyst is a chemical involved in, but not changed by, a chemical reaction. Many enzymes function by lowering the activation energy of reactions. By bringing the reactants closer together, chemical bonds may be weakened and reactions will proceed faster than without the catalyst. Answer : (d)
Q.24
NAD+ and NADP+ resemble each other in ability to ... .... [ Manipal 2002]
0%
a) Give out a proton
0%
b) Take up two electrons at one time
0%
c) Take up two hydrogen atoms
0%
d) Take up one electron at one time
Explanation
In cells, most oxidations are accomplished by the removal of hydrogen atoms. Both of these coenzymes play crucial roles in this. Each molecule of NAD+ (or NADP+) can acquire two electrons; that is, be reduced by two electrons. However, only one proton accompanies the reduction. The other proton produced as two hydrogen atoms are removed from the molecule being oxidized is liberated into the surrounding medium. Answer : (b)
Q.25
In water, the angle between the atoms of Hydrogen and one atom of Oxygen is ... ... [ CBSE 1997]
0%
a) 180°
0%
b) 104.5°
0%
c) 106.5°
0%
d) 154.8°
Explanation
In liquid water, the mean O-H length is about 0.097 nm, the mean H-O-H angle is about 106°, and the mean negative charge on the oxygen atom is about 70% of that of an electron with each hydrogen atom positively charged sharing the neutralizing charge. Answer : (b)
Q.26
DNA differs from RNA in having ... ... [ kerala 2000 ]
0%
a) Cytosine but no guanine
0%
b) Thymine but no uracil
0%
c) Uracil but no thymine
0%
d) Thymine but no cytosine
Explanation
DNA have Thymine but no uracil. DNA uses the bases adenine, thymine, cytosine, and guanine; RNA uses adenine, uracil, cytosine, and guanine. DNA is a double-stranded molecule, while RNA is a single-stranded molecule. DNA is stable under alkaline conditions, while RNA is not stable Answer : (b)
Q.27
Structure of DNA was given by .... .. [BHU 1991]
0%
a) Kornberg
0%
b) Nirenberg
0%
c) Watson and Crick
0%
d) Holley and Nirenberg
Explanation
The three-dimensional structure of DNA, first proposed by James D. Watson and Francis H. C. Crick in 1953 Answer : (c)
Q.28
According to IUB system of nomenclature the enzymes are divided into
0%
a) 4 classes
0%
b) 6 classes
0%
c) 8 classes
0%
d) 12 classes
Explanation
Answer:(b)
Q.29
Which one is essential for nitrogen fixation? .... .... [ CBSE 2003]
0%
a) Copper
0%
b) Zinc
0%
c) Manganese
0%
d) Molybdenum
Explanation
Each of the nitrogen-fixing bacteria employs the same enzyme , nitrogenase. The nitrogenase enzyme is shaped something like a butterfly, and contains an atom of molybdenum at its core that is crucial for the reaction. Soils deficient in molybdenum cannot sustain effective nitrogen fixation, and monitoring soil for this element is important to ensure maximum fixation in managed fields or pastures. Answer : (d)
Q.30
Most abundant enzyme is ... ... [ CBSE 1999 ]
0%
a) Catalase
0%
b) Rubisco
0%
c) Nitrogenase
0%
d) invertase
Explanation
Rubisco (d-ribulose 1,5-bisphosphate carboxylase/oxygenase) is responsible for the vast majority of global carbon fixation and has been to be the most abundant protein on Earth Answer : (b)
Q.31
Chitin is strengthen by
0%
a) Calcium phosphate
0%
b) Magnesium phosphate
0%
c) Calcium carbonate
0%
d) Magnesium carbonate
Explanation
Answer : (c)
Q.32
In a cell, digestive enzymes mostly occur in .... .... [ Har PMT 1994]
0%
a) Ribosomes
0%
b) Lysosomes
0%
c) Mitochondria
0%
d) Plastids
Explanation
Lysosomes are membrane-bound organelles that contain digestive enzymes that break down proteins, lipids, carbohydrates, and nucleic acids. Answer : (b)
Q.33
Which one is not a coenzyme? ... .... [CPMT 2004]
0%
a) NAD+
0%
b) NADPH
0%
c) FAD
0%
d) ATP
Explanation
NADPH oxidase (nicotinamide adenine dinucleotide phosphate oxidase) is a membrane-bound enzyme complex that faces the extracellular space. A coenzyme is an organic non-protein compound that binds with an enzyme to catalyze a reaction. Nicotinamide Adenine Dinucleotide (NAD) and Flavin Adenine Dinucleotide (FAD) are coenzymes involved in reversible oxidation and reduction reactions. The molecule ATP (adenosine triphosphate) can function as a coenzyme. When a phosphate group is removed, turning ATP into ADP (adenosine diphosphate), energy is released. Since many chemical reactions require energy, cells can use ATP to give energy to a reaction to assist in changing the substrate to product. Answer : (b)
Q.34
Energy made available in catabolic reactions is immediately stored in ... .... [ CPMT 1991]
0%
a) Glucose
0%
b) NADH
0%
c) ATP
0%
d) DNA
Explanation
Adenosine triphosphate (ATP) is the energy molecule of the cell. During catabolic reactions, ATP is created and energy is stored until needed during anabolic reactions. Answer : (c)
Q.35
Which is least harmful ... .... [ DPMT 2007]
0%
a) Saturated fat
0%
b) Oils
0%
c) Cholesterol
0%
d) Polyunsaturated fat
Explanation
Polyunsaturated fats are fats in which the constituent hydrocarbon chain possesses two or more carbon–carbon double bonds. Polyunsaturated fat can be found mostly in nuts, seeds, fish, seed oils, and oysters. polyunsaturated fatty acids may protect against atherosclerosis. Saturated fats raise your LDL (bad) cholesterol. High LDL cholesterol increases your risk for heart disease and stroke. Oils contains saturated fats can drive up total cholesterol, and tip the balance toward more harmful LDL cholesterol, which prompts blockages to form in arteries in the heart and elsewhere in the body. Answer : (d)
Q.36
Water is ideal material for disposal of excess solar energy because ... .. [ Tamil Nadu 2001]
0%
a) Water is easily available and its specific heat is high
0%
b) Water evaporates from leaf surface and its latent heat is high
0%
c) Water is general solvent
0%
d) Upward movement of water creates a difference in water potential
Explanation
Answer : (b)
Q.37
Unsaturated fats are made saturated by .... .... [ Har PMT 2002]
0%
a) Polymerisation
0%
b) Hydrogenation
0%
c) Dehydrogenation
0%
d) Hybridisation
Explanation
Unsaturated fatty acids may be converted to saturated fatty acids by the relatively simple hydrogenation reaction. Answer : (b)
Q.38
Number of oxygen atoms in lipid molecules is always ........ as compared to number of carbon atoms ... [ HPPMT 2001]
0%
a) Less
0%
b) More
0%
c) Equal
0%
d) Double
Explanation
Lipids are made up of carbon, hydrogen, oxygen with a H:O ration of > 2:1 These molecules have lots and lots of carbons and hydrogens (tens, hundreds or even thousands) yet they only contain six oxygens. Answer : (a)
Q.39
~P in ATP represents .... ... [ CPMT 1996]
0%
a) Two bonds with high energy
0%
b) Two moles of phosphorous
0%
c) Three atoms of high energy phosphate
0%
d) None of the above
Explanation
ATP is a nucleotide consisting of an adenine base attached to a ribose sugar, which is attached to three phosphate groups. These three phosphate groups are linked to one another by two high-energy bonds called phosphoanhydride bonds. Answer : (a)
Q.40
Lactic dehydrogenase (LHD) that takes part in catalysis of pyruvate → lactate is an example of ... ... [ JIPMER 1997]
0%
a) Isoenzyme
0%
b) Zymogen
0%
c) Coenzyme
0%
d) Apoenzyme
Explanation
Isozymes (also known as isoenzymes) are enzymes that differ in amino acid sequence but catalyze the same chemical reaction Lactate dehydrogenase (LDH or LD) the conversion of lactate to pyruvate and back, as it converts NAD+ to NADH and back. lactate dehydrogenase (LDH). This enzyme is used to catalyze the synthesis of glucose in anaerobic metabolism of glucose Answer : (a)
Q.41
Chitin is polymer of ... ... [ Uttarakhand 2001]
0%
a) N-acetyl muramic acid
0%
b) N-acetyl gluconic acid
0%
c) N-acetyl glucosamine
0%
d) None of the above
Explanation
Chitin (C8H13O5N)n, a long-chain polymer of N-acetylglucosamine, is a derivative of glucose. Answer : (c)
Q.42
Water is important for the functioning of body as ... .... [ RPMT 2002]
0%
a) It releases energy
0%
b) Provides H+ ions
0%
c) Kill microorganism
0%
d) It is a very good solvent
Explanation
Water in all its cells, organs, and tissues to help regulate its temperature and maintain other bodily functions. Water is important for the functioning of body as it is a very good solvent Answer : (d)
Q.43
ADP has ... ... [ BHU 2007]
0%
a) One high energy bond
0%
b) Two high energy bonds
0%
c) Three high energy bonds
0%
d) None of the above
Explanation
ADP (Adenosine Diphosphate) contains high energy bonds located between each phosphate group. Answer : (a)
Q.44
Specificity of protein in enzyme action depends upon .... .... [ BHU 1992]
0%
a) Active sites
0%
b) Linear sequence of amino acids
0%
c) Km constant
0%
d) Turn over number
Explanation
Proteins are made of units called amino acids, and in enzymes that are proteins, The set of amino acids found in the active site, along with their positions in 3D space, give the active site a very specific size, shape, and chemical behavior. These amino acids, an enzyme's active site is uniquely suited to bind to a particular target—the enzyme's substrate or substrates—and help them undergo a chemical reaction. Answer : (b)
Q.45
Macromolecule most common in plant cell walls is ... ... [ kerala 2001]
0%
a) Glycogen
0%
b) Starch
0%
c) Protein
0%
d) Cellulose
Explanation
Plant cell walls are primarily made of cellulose, which is the most abundant macromolecule on Earth. Answer : (d)
Q.46
Functional protein is ... ... [ BHU 1994]
0%
a) Enzyme
0%
b) Collagen
0%
c) Ossein
0%
d) Vitamin
Explanation
Enzymes are proteins, and they make a biochemical reaction more likely to proceed by lowering the activation energy of the reaction, thereby making these reactions proceed thousands or even millions of times faster than they would without a catalyst. Answer : (a)
Q.47
A plant proteinase is ... ... [ MPPMT 1989]
0%
a) Papain
0%
b) Trypsin
0%
c) Pepsin
0%
d) Urease
Explanation
Papain is found naturally in papaya (Carica papaya L.) manufactured from the latex of raw papaya fruits. Answer : (a)
Q.48
Among nitrogen bases of nucleic acids, double ring is found in ... .... [ AMU 2009]
0%
a) Thymine
0%
b) Cytosine
0%
c) Uracil
0%
d) Guanine
Explanation
Purines Double carbon-nitrogen ring with four nitrogen atoms Adenine and Guanine, are purines Answer : (d)
Q.49
Enzyme complex involved in alcoholic fermentation is ... ... [ CPMT 2008]
0%
a) Lipase
0%
b) Invertase
0%
c) Zymase
0%
d) Amylase
Explanation
Zymase is an enzyme complex that catalyzes the fermentation of sugar into ethanol and carbon dioxide. Answer : (c)
Q.50
Which ones are not true? ... ..[ kerala 2008] i) Glycerol is a 3-carbon alcohol with 3-OH groups as binding sites ii) Waxes are esters of long chain alcohols and saturated fatty acids iii) The term protein was coined by Mulder iv) Agar is an indispensable polysaccharide, being a complex polymer of glucose and sulphur containing carbohydrates
0%
a) i and ii only
0%
b) iv only
0%
c) i and iv only
0%
d) i, ii and iv only
Explanation
Agar is a polymer made up of subunits of the sugar galactose. So Statement 'iv' is NOT correct Answer : (b)
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