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CBSE Questions for Class 12 Engineering Chemistry Biomolecules Quiz 8 - MCQExams.com
CBSE
Class 12 Engineering Chemistry
Biomolecules
Quiz 8
Baking powder is more commonly used to make cakes or bread "rise". Filler in baking powder is:
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$$NaHCO_3$$
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$$Ca(H_2PO_4)_2 $$
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starch
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$$NaAl(SO_4)_2$$
Explanation
An improved combination of baking powder contains about 40% starch, 30% $$NaHCO_3$$, 20% $$NaAl(SO_4)_2$$ and 10% $$Ca(H_2PO_4)_2$$.
Here starch acts as
filler
.
Which vitamin is not obtained from plants ?
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Cyanocobalamine
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Thiamine
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Pyridoxine
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$$\alpha-$$ tocopherol
Explanation
Cyanocobalamine is vitamin $$B_{12}$$. It is manufactured by bacteria and can only be found naturally in animal products. Its main sources are liver of ox, fish, crab, milk, cheese, etc. Thus, it is not obtained from plants.
The vitamin which is neither soluble in water nor in fat is:
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Biotin
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Phylloquinone
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Thiamine
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Pyridoxine
Explanation
Biotin (vitamin$$ H$$) is neither soluble in water nor in fat.
Option A is correct.
A peptide hormone is:
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estrone
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testosterone
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insulin
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corticoid
Explanation
Insulin is a peptide hormone produced by beta cells of the pancreatic islets.
It is considered to be the main anabolic hormone of the body. Insulin contains two polypeptide chains with 21 and 30 amino acids which are joined together by
sulphur
bridges. Hence, it is a peptide hormone.
The presence or absence of hydroxyl group on which carbon atom of sugar differentiates RNA and DNA ?
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1st
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2nd
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3rd
0%
4th
Explanation
Ribose contains -OH at $$C_2$$ but deoxyribose dos not.
Intermediate common to fatty acid and carbohydrate oxidation is ______________.
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Pyruvate
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Acetyl CoA
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Oxaloaxetate
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Succinate
Explanation
B. Acetyl CoA
Solution: The oxidation of fatty acid and carbohydrate ultimately forms ATP. The common intermediate in all these oxidation is Acetyl CoA. SAcetyl CoA is snthesized in mitochondria by
a number of reactions: oxidative decarboxylation of pyruvate, beta oxidation of fatty acids.
So the correct answer is "Acetyl CoA".
Which of the following hexoses will form the same osazone when treated with excess phenyl hydrazine?
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D-glucose, D-fructose and D-galactose
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D-glucose, D-fructose and D-mannose
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D-glucose, D-mannose and D-galactose
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D-fructose, D-mannose and D-galactose
Explanation
D-glucose, D-fructose, and D-mannose form the same osazone when treated with an excess of phenylhydrazine because they differ only in the configuration of 1st and 2nd carbon atoms which are transformed to the same form.
Which of the following is the correct statement ?
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Starch is a polymer of $$\alpha$$-glucose
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Amylose is a component of cellulose
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Proteins are composed of only one type of amino acid
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In cyclic structure of fructose, there are four carbons and one oxygen atom
Explanation
Starch is also known as amylum which occurs in all green plants. A molecule of starch $$(C_6H_{10}O_5)$$ is built of a large number of $$\alpha$$-glucose ring joined through oxygen-atom.
Hence,option A is correct.
Many pathogens produce cellulolytic, enzymes which act upon the host cell wall. The correct sequence of the given cellulolytic enzymes that are involved in the breakdown of cellulose is?
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Cellobiase, $$C_1$$ enzyme, Cx enzyme
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Cellobiase, Cx enzyme, $$C_1$$ enzyme
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$$C_1$$ enzyme, Cx enzyme, Cellobiase
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Cx enzyme, $$C_1$$ enzyme, Cellobiase
Explanation
Enzymatic hydrolysis of cellulose is an important reaction in nature for it marks the first step in the decay of cellulose, the most abundantly occurring organic material by which many pathogens enter the host cell wall. Whitaker (1953-1954) has concluded that his Myrothecium verrucaria cellulase is a single enzyme capable of hydrolyzing native cellulose C1 enzyme followed by Cx enzyme then at last cellobiase . Cellobiase is involved in the last step of the process of breaking down cellulose, a molecule made up of bundled long chains of glucose that are found in plant cell walls, to glucose. This is a natural process that is used by fungi to produce glucose as a food source.
So, the correct option is 'C'.
The number of moles of substrate converted per minute by one mole of enzyme is called.
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Turnover number
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Substrate number
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Enzyme number
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Peptide number
Explanation
Turnover number is defined as the number of substrate molecules transformed per minute by a single enzyme molecule when the enzyme is the rate-limiting factor. he higher the turn over number, the more efficient an enzyme. It depends upon all the active points present over enzymes.
So, the correct option is 'A'.
Consider the following statements about enzymes.
a. Most enzymes are proteinaceous, although some are RNA molecules
b. The specificity of an enzyme is due to its well-defined three dimensional structure and the active site present in it.
c. Prosthetic group is loosely bound to the apoenzyme part of the enzyme.
d. Portions, prosthetic group and apoenzyme are enzymatically inactive when separated from each other.
Pick the correct ones from these statements.
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$$1, 2$$ and $$3$$ are correct
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$$1, 3$$ and $$4$$ are correct
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$$1, 2$$ and $$4$$ are correct
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$$2, 3$$ and $$4$$ are correct
A $$25,000$$ Da protein contains a single binding site for a molecule(ligand), whose molecular weight is $$2,500$$Da. Assuming high affinity and physiologically irreversible binding, the amount of the liquid required to occupy all the binding sites in $$10$$mg protein will be
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$$0.1$$mg
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$$1$$mg
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$$10$$mg
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$$100$$mg
Explanation
It is given that 25,000 Da protein contains single binding site for ligand with molecular weight 2,500 Da.
Hence, 10 mg of protein will require approximately 10 x 2,500 / 25, 000 = 1 mg of ligand to occupy all the binding sites in protein.
Thus, the correct answer is option B.
Enzymes play an essential role in the body because ________.
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they provide energy
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they control nervous system
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these are the structural part of body
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these are the catalyst of biochemical activity
Explanation
Enzymes are biological catalysts. Catalysts are substances that increase the rate of chemical reactions without being used up. Thus the correct answer is option D.
On hydrolysis of starch, we finally get:
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Glucose
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Fructose
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Both (a) and (b)
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Sucrose
Explanation
Starch is a polymer of D-glucose units, thus on hydrolysis it only gives glucose.
From the following substances, which carbohydrates has the maximum sweetness?
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Sucrolose
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Saccharin
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Aspartme
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Alitame
Explanation
All sugars are compared relative to sucrose on the basis of sweetness. Hence, sucrose is rated one in terms of sweetness.
Alitame is the sweetest among the following with a sweetness rating of 2000, while saccharin, aspartame, and sucralose have a rating of 400, 180, and 600 respectively
$${Q}_{10}$$ value for enzyme is generally found to be____________.
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$$1$$
0%
$$2$$
0%
$$4$$
0%
$$5$$
Which of the following is NOT an enzyme?
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Lipase
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Amylase
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Trypsin
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Bilirubin
Explanation
Bilirubin is the product produced from the breakdown of haemoglobin. It is a yellow compound that occurs in the normal catabolic pathway that breaksdown heme in vertebrates. This catabolism is a necessary process in the body's clearance of waste products that arise from destruction of abnormal blood cells.Its level or range is measured for monitoring the liver or gallbladder issues. It is not an enzyme.
So the correct option is (D).
Name the main constituent of the food, in the absence of that one cannot live
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Carbohydrates
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Mineral salts
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Proteins
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Vitamins
Explanation
Carbohydrate is the major source of energy without which one cannot live. It is because carbohydrate is broken down to form instant energy in the form of glucose which can be converted into ATP and thus used for the regular functioning of the cell. Other forms of energy like proteins, vitamins, and minerals are the extra components that are not directly involved in the formation of energy.
So, the correct option is 'carbohydrates'
Various types of crystals of calcium carbonate or oxalate are reported in certain families which can also be regarded as aid to taxonomy. Crystals of gypsum are present either singly or in clusters in
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Tomarix dioica
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Ficus benghalensis
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Momordica charantia
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Nymphaea sp.
Explanation
Crystals of calcium oxalate, starch grains, stone cells with lignified walls, brown tannin cells, and crystals of gypsum are present in the cells of
Ficus benghalensis,
they belong to family Moraceae. The presence of different crystals is the characteristic feature that distinguishes families from each other.
So, the correct option is '
Ficus benghalensis'.
Which cell organelle is not correctly associated with an appropriate enzyme or protein?
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Mitochondria-cytochrome C
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Rough endoplasmic reticulum-ribosomes
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Peroxisomes-catalase
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Nuclear membrane-amino acid permease
Explanation
Amino acid permeases are involved in the transport of amino acids into the cell. They are associated with the cell or plasma membrane and not with the nuclear membrane.
So, the correct answer is 'Nuclear membrane-amino acid permease'.
Enzymes differ from inorganic catalysts in
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Not being used up in chemical reactions
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Working at high.temperature
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Being proteinaceous in nature
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Working at high pH
Explanation
Enzymes are the biocatalyst that differs from the inorganic catalyst in been proteinaceous in nature.
So, the correct option is 'Being proteinaceous in nature'.
The catalytic power of enzyme is represented by :-
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$${ V }_{ max }$$
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$${ K }_{ m }$$ constant
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Turn over number
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Both (2) & (3)
Explanation
The catalytic power of an enzyme is basically the enzyme’s turnover. It is generally denoted by Vmax.
So, the correct answer is '
V
m
a
x'.
Which one of the following is not an attribute of enzymes?
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They are specific in nature
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They are used in chemical reactions
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They are thermolabile in nature
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They are proteinaceous in nature
Explanation
Enzymes are the biomacromolecules which catalyze the reactions in the body.
So, the correct answer is 'They are used in chemical reactions'.
The three $$p{K}_{a}$$ values of aspartic acid are 1.89, 3.65 and 9.The pH of the amino acid is ?
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2.77
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6.62
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5.74
0%
7.0
Explanation
PKa of Aspartic acid are $$1.89$$, $$3.65$$ and $$9.66$$.
$$pH$$ of Amino acid $$=\dfrac { 1.89+3.65 }{ 2 } =2.77$$
Carbohydrates are ___________.
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used to make a paper
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produced as an intermediate in the synthesis of proteins
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the polyhydroxy aldehyde or polyhydroxy ketone
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all of these
Explanation
Carbohydrates are polyhydroxy aldehydes or polyhydroxy ketone. Cellulose is a carbohydrate used to make a paper. Carbohydrates are also produced as an intermediate in the synthesis of protein.
Peristent nucellus is called as _________ and is found in _________.
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Perisperm, black pepper
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Perisperm, groundnut
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Endosperm, black pepper
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Endosperm, groundnut
Explanation
In some seeds, remains of nucellus persist. This residual nucellus which persists in the seed is called perisperm, e.g., black pepper, coffee, castor, cardamom, Nymphaea.
Which of the following is not the example of carbohydrate?
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Glucose
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Maltose
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Glycine
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Fructose
Explanation
Here Glucose, Maltose, and Fructose are carbohydrate. Glycine is not a carbohydrate. It is a protein.
The general formula of carbohydrates is:
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$${C}_{n}{H}_{2n+1}O$$
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$${C}_{n}{H}_{2n}O$$
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$${C}_{n}{({H}_{2}O)}_{n}$$
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$${C}_{n}{({H}_{2}O)}_{2n}$$
Explanation
The general formula for any carbohydrate is $${(C{H}_{2}O)}_{n} = {C}_{n}{({H}_{2}O)}_{n}$$
Starch is made by photosynthesis in the leaves of plants. It is found in rice, potatoes, and many vegetables sources. It can be detected with a drop of iodine. In the presence of starch, iodine:
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vapourises
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turns blue
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decolourises
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turns into a black solid
Explanation
(B) Turns blue
When starch is mixed with iodine in water, an intensely blue colored starch/iodine complex is formed.
Carbohydrates contains carbon, hydrogen, and oxygen molecules.
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True
0%
False
Explanation
Carbohydrates are the biomolecules containing carbon, hydrogen, and oxygen respectively. They are also called hydrates of carbon.
Which carbon atom of deoxy Ribose sugar in DNA does NOT contain $$-\overset{|}{\underset{|}{C}}-OH$$ bond?
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$$C_5$$
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$$C_3$$
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$$C_2$$
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$$C_1$$
Which of the following treatment will convert starch directly into glucose?
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Heating with dilute $${H}_{2}{SO}_{4}$$
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Fermentation by diastase
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Fermentation by zymase
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Heating with dilute $$NaOH$$
Explanation
Answer: $$(A)$$ Heating with diute $${H}_{2}S{O}_{4}$$
Commercially glucose is obtained by hydrolysis of starch by heating it with dilute $${H}_{2}S{O}_{4}$$ at 393 K under pressure.
$$\underset{Starch}{{\left({C}_{6}{H}_{10}{O}_{5} \right)}_{n}} + n{H}_{2}O \xrightarrow[393 K; \; 2-3 atm]{{H}^{+}} \underset{Glucose}{n{C}_{6}{H}_{12}}{O}_{6}$$
Which of the following reactions is not enzyme-mediated in biological system?
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Dissolving $$CO_2$$ in water
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Unwinding the two strands of DNA
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Hydrolysis of sucrose
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Formation of peptide bond
Explanation
$$\textbf{Correct option: (A)}$$
$$\textbf{Explanation for correct option:}$$
$$\bullet$$ Dissolving
$${CO_2}$$
in water does not require an enzyme.
$$\bullet$$
Solubility of
$${CO_2}$$
in water can be increased with decrease in temperature, a principle used in carbonated drinks.
$$\textbf{Explanation for incorrect options:}$$
$$\bullet$$ DNA h
elicases move along the double-stranded DNA and separate the strands by breaking hydrogen bonds at the expense of energy from ATP.
$$\bullet$$
The hydrolysis of sucrose generates an equimolar mixture of fructose and glucose, commercially sucrose is also known as invert sugar. This (hydrolysis of sucrose) reaction is mediated by the enzyme invertase/sucrase.
$$\bullet$$
Peptidyl transferase is an enzyme that catalyzes peptide bond formation.
A compound which contains both ______ and ______ is called amino acid. The amino acids in polypeptide chain are joined by ______ bonds.
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amino, carboxylic group, ester
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amino, carboxylic group, peptide
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nitrogen, carbon, glycosidic
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hydroxy, carboxylic group, peptide
Explanation
Amino acids are organic compounds containing amine $$(-N{H}_{2})$$ and carboxyl (-COOH) functional groups.
Amino Acids Are Linked by peptide bonds formed by linking the $$\alpha$$-carboxyl group of one amino acid to the $$\alpha$$-amino group of another amino acid.
The $$\alpha$$ amino acid which contains the aromatic side chain is:
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proline
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tyrosine
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valine
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serine
Explanation
To different degrees, all aromatic amino acids absorb ultraviolet light. Tyrosine and tryptophan absorb more than do phenylalanine. Tyrosine is the only one of the aromatic amino acids with an ionizable side chain.
Vitamin C must be supplied regularly in diet because ?
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it is water soluble hence excreted in urine and can't be stored in the body
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it is fat soluble hence stored in the body and cannot be used on regular basis
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it is required in a large amount by the body hence supplied regularly
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it is water soluble hence used by the body on daily basis and is to be suppled regularly
Explanation
Vitamin C must be consumed regularly in diet because it is water soluble and cannot be stored in body. It get flushed from our body, hence must be consumed daily.
Bases common to RNA and DNA are?
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adenine, guanine, cytosine
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adenine, uracil, cytosine
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adenine, guanine, thymine
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guanine, uracil, thymine
Explanation
The purines adenine (A) and guanine (G) and the pyrimidine cytosine (C) are commonly present in both DNA and RNA. The pyrimidine thymine (T) present in DNA is replaced by the pyrimidine uracil (U) in RNA.
What is the basic formula for starch?
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$${ \left( { C }_{ 6 }{ H }_{ 12 }{ O }_{ 6 } \right) }_{ n }$$
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$${ \left( { C }_{ 6 }{ H }_{ 10 }{ O }_{ 5 } \right) }_{ n }$$
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$${ \left( { C }_{ 12 }{ H }_{ 22 }{ O }_{ 11 } \right) }_{ }$$
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$${ \left( { C }_{ 6 }{ H }_{ 12 }{ O }_{ 4 } \right) }_{ n }$$
Explanation
Starch is a polysaccharide comprising glucose monomers joined in $$\alpha$$-1,4 linkages. The basic chemical formula of the starch molecule is $${\left( {C}_{6}{H}_{10}{O}_{5} \right)}_{n}$$.
Hence, option $$B$$ is correct.
Which of the following is not true about amino acids?
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They are constituents of all proteins
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Alanine having one amino and one carboxylic group
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Most naturally occurring amino acids have D-configuration
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Glycine is the only naturally occurring amino acid which is optically inactive
Explanation
All naturally occurring proteins from all living organisms consist of L amino acids. Most naturally occurring chiral amino acids are S, with the exception of cysteine.
Hence, C is not true.
Match the name of vitamins in column I with their sources in column II and mark the appropriate choice.
Column I
Column II
(A) Vitamin $${B}_{1}$$
(i) Milk, yeast, cereals
(B) Vitamin $${B}_{12}$$
(ii) Meat, fish, egg
(C) Vitamin A
(iii) Carrots, butter, papaya
(D) Vitamin C
(iv) Citrus fruits, amla, green leafy vegetables
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(A) $$\rightarrow$$ (iii), (B) $$\rightarrow$$ (iv), (C) $$\rightarrow$$ (i), (D) $$\rightarrow$$ (ii)
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(A) $$\rightarrow$$ (ii), (B) $$\rightarrow$$ (i), (C) $$\rightarrow$$ (iii), (D) $$\rightarrow$$ (iv)
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(A) $$\rightarrow$$ (iv), (B) $$\rightarrow$$ (iii), (C) $$\rightarrow$$ (ii), (D) $$\rightarrow$$ (i)
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(A) $$\rightarrow$$ (i), (B) $$\rightarrow$$ (iii), (C) $$\rightarrow$$ (ii), (D) $$\rightarrow$$ (iv)
Explanation
Vitamin $$B_1$$ is mostly found in meat, fish, and poultry products.
Vitamin $$B_{12}$$ is found in cereals, yeast, and most of the milk and milk products.
Orange and Yellow vegetables are the major source of Vitamin A. Carrots, butter, papaya are the source of Vitamin A.
Vitamin C is found naturally in fruits(citrus fruits and their juices) and green leafy vegetables.
A-ii, B-i, C-iii, D-iv
Option B is correct.
Vitamin $${B}_{2}$$, a water soluble vitamin is also known as:
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ascorbic acid
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riboflavin
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thiamine
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pyridoxine
Explanation
Vitamin $${B}_{2}$$ is the only water-soluble vitamin which is used as a food coloring known as riboflavin. It is named for its color — the Latin word flavus means “yellow.”
Which is a fat-soluble vitamin?
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Vitamin A
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Vitamin $${B}_{6}$$
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Vitamin C
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Vitamin $${B}_{2}$$
Explanation
A vitamin that can dissolve in fats and oils. Fat-soluble vitamins are absorbed along with fats in the diet and can be stored in the body's fatty tissue. They come from plant and animal foods or dietary supplements. Vitamins A, D, E, and K are fat-soluble.
If one strand of DNA has the sequence ATGCTTGA, the sequence in the complementary strand would be:
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TCCGAACT
0%
TACGTAGT
0%
TACGAATC
0%
TACGAACT
Explanation
The base pairs on one strand of the DNA bind with the base pairs of the other strand specifically. A always pairs with T with two hydrogen bonds and G always pairs with C with three hydrogen bonds. So if one strand is ATGCTTGA then the complementary strand will be TACGAACT.
Consider the given compound and arrange X, Y, Z in order of increasing acid strengths?
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X> Z> Y
0%
Z> X> Y
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X> Y> Z
0%
Y> X> Z
Explanation
$$-COOH\rightarrow $$ more gives acidic as it gives $$H^+$$ easily.
Near to $$X$$ there is $$Z$$ which is more acidic than $$Y$$ because of $$-I$$ effect decrease with distance.
Which of the following acids is a vitamin?
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Aspartic acid
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Ascorbic acid
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Adipic acid
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Saccharic acid
Explanation
Vitamin C, also known as ascorbic acid is a vitamin found in food and used as a dietary supplement.
Option B is correct.
Match column I with column II and mark the appropriate choice.
Column I
Column II
(A) Pentise sugar in DNA
(i) Ascorbic acid
(B) Nucleic acid
(ii) Uracil
(C) RNA
(iii) Genetic material
(D) Vitamin
(iv) Furanose structure
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(A) $$\rightarrow$$ (iv); (B) $$\rightarrow$$ (iii); (C) $$\rightarrow$$ (ii); (D) $$\rightarrow$$ (i)
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(A) $$\rightarrow$$ (iii); (B) $$\rightarrow$$ (ii); (C) $$\rightarrow$$ (iv); (D) $$\rightarrow$$ (i)
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(A) $$\rightarrow$$ (ii); (B) $$\rightarrow$$ (iii); (C) $$\rightarrow$$ (iv); (D) $$\rightarrow$$ (i)
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(A) $$\rightarrow$$ (i); (B) $$\rightarrow$$ (ii); (C) $$\rightarrow$$ (iii); (D) $$\rightarrow$$ (iv)
Explanation
$$A.$$ Pentise sugar in DNA is fructose (Furanose structure)
$$B.$$ Neucleic acid contains genetic materic
$$C.$$ RNA has uracil
$$D.$$ Vitamin is ascorbic acid.
Which of the following pairs form the same osazone?
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Glucose and Fructose
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Glucose and Galactose
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Glucose and Arabinose
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Lactose and Maltose
Explanation
When sugars react with an excess of phenylhydrazine, a class of compounds known as osazone is formed.
Glucose and fructose differ in the arrangement of atoms around the $$C-1$$ and $$C-2$$ carbon. When both of them react with three molecules of phenylhydrazine, the formation of osazone crystals makes the difference between the carbon atoms in their chain and hence they form the same osazone.
Hence, the correct answer is option $$\text{A}$$.
Within the list shown below, the correct pair of structures of alanine in $$pH$$ range $$2-4$$ and $$9-11$$ is:
I. $${H}_{3}{N}^{+}CH({CH}_{3}){CO}_{2}H$$
II. $${H}_{2}NCH({CH}_{3}){CO}_{2}^{-}$$
III. $${H}_{3}{N}^{+}CH({CH}_{3}){CO}_{2}^{-}$$
IV. $${H}_{2}NCH({CH}_{3}){CO}_{2}H$$
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I, II
0%
I, III
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II, III
0%
III, IV
Explanation
As the isoelectric point of Alanine is 6.1.
At $$ p{H} $$ below p$$ ^{I} $$ it has $$ NH_{3}^{\bigoplus} $$
At $$ p{H} $$ above p$$ ^{I} $$ it has
$$ COO^{\ominus } $$
Option A is correct.
In disaccharides, if the reducing groups of monosaccharides i.e. aldehydic or ketoinc groups are bonded, these are non-reducing sugars. Which of the following disaccharides is a non-reducing sugar?
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0%
0%
0%
Explanation
$$\textbf{Explanation:}$$
Reducing Sugar: Any carbohydrate whose structure contains an Aldehydic or Hemiacetal group is a reducing sugar. This free aldehydic or hemiacetal group can be easily oxidised accompanying the reduction of oxidising agent.
In option B the aldehyde group of glucose and keto group of fructose involved in the glycosidic linkage. So, this sugar lacks free aldehyde or hemiacetal group. Therefore, this is a non reducing sugar.
$$\textbf{Explanation of the incorrect options}$$
A, C and D have free hemiacetal groups. So, they are reducing sugars.
Which substance is not present in nucleic acids?
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Cytosine
0%
Adenine
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Thymine
0%
Guanidine
Explanation
A nucleotide consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base.
The bases used in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T). In RNA, the base uracil (U) takes the place of thymine.
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