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WorksheetsBiomolecules- Proteins and Carbohydrates
Total questions: 22
Worksheet time: 17mins
Name
Class
Date
1.
The amino group in amino acids is always covalently bonded to:
a)
β-carbon of the carboxylic acid.
b)
α- carbon of the carboxylic acid.
c)
oxygen atom of the carboxylic group.
d)
carboxyl carbon of the carboxyl group.
2.
Amino acids present in most of the biologically active peptides and proteins are:
a)
levorotatory
b)
dextrorotatory
c)
either levorotatory or dextrorotatory.
d)
neither levorotatory or nor dextrorotatory.
3.
What is a more common and familiar name for diamino-monocarboxylic amino acids?
a)
Polar amino acids
b)
Basic amino acids
c)
Acidic amino acids
d)
Aliphatic amino acids
4.
Which part of the amino acid generally gains a positive charge in highly acidic environment?
a)
Amino acid side chain.
b)
Amino group attached to the α- carbon of the amino acid moiety.
c)
Carboxyl group attached to the α- carbon of the amino acid moiety.
d)
Hydrogen atom attached to the α- carbon of the amino acid moiety.
5.
Which level of structural organisation of a polypeptide if changed leads to complete change in all the levels of structural organisation of a polypeptide?
a)
Primary
b)
Secondary
c)
Tertiary
d)
Quaternary
6.
Zwitterion has no net charge but a zwitterion of an amino acid contains:
a)
a negatively charged amino group and a positively charged carboxyl group.
b)
a positively charged amino group and a negatively charged carboxyl group.
c)
a positively charged amino acid side chain and a negatively charged hydrogen atom attached to the α- carbon of the amino acid.
d)
a negatively charged amino acid side chain and a positively charged hydrogen atom attached to the α- carbon of the amino acid.
7.
Why the side chains of the amino acids in α- helix are protruded outwards?
a)
To prevent steric hindrance.
b)
To form covalent or hydrogen bonds with other polypeptide molecules.
c)
Side chains of the α- helix interact among themselves to form bonds with each other.
d)
To interact with the solvent molecules in which the polypeptide molecules are suspended.
8.
What level of structural organisation is expected in a peptide like TRH (Thyrotropin Releasing hormone) composed of only three amino acids?
a)
Primary
b)
Secondary
c)
Tertiary
d)
Quaternary
9.
What is the identifying feature of the last amino acid of a polypeptide chain?
a)
The last amino acid of a polypeptide chain has a free amino group.
b)
The last amino acid of a polypeptide chain has a free carboxyl group.
c)
The last amino acid of a polypeptide chain has a free side chain attached to the α- carbon of the amino acid.
d)
The last amino acid of a polypeptide chain has a free hydrogen atom attached to the α- carbon of the amino acid.
10.
Which of the following is not true about alanine?
a)
At pH1, the overall charge is +1
b)
At pH1, it will move towards cathode
c)
an equimolar mixture of D and L alanine does not rotate the plane polarized light
d)
contains a branched side chain
11.
Which of the following statements about the structures of water soluble proteins are incorrect?
P: they contain tightly packed amino acid residues in their interior
Q: most of their nonpolar residues face the aqueous solvent
R: the main chain NH and CO groups are often involved in H-bonded secondary structures
S: all of these contains B-sheet structures
P: they contain tightly packed amino acid residues in their interior
Q: most of their nonpolar residues face the aqueous solvent
R: the main chain NH and CO groups are often involved in H-bonded secondary structures
S: all of these contains B-sheet structures
a)
only P
b)
P and Q
c)
Q and S
d)
R and S
12.
Which of the following biomolecules is not a homopolymer?
a)
Cellulose
b)
Glycogen
c)
Peptidoglycan
d)
Starch
13.
In solution the common monosaccharide sugars exist as:
a)
an entangled mass of monosaccharide molecules.
b)
cyclic or ring compounds.
c)
mixture of straight chain and cyclic forms.
d)
straight chain compounds.
14.
In Benedict’s test for reducing sugars, the reducing sugar molecules:
a)
oxidises the cupric ions to cuprous ions within the benedict’s solution.
b)
oxidises the cuprous ions to cupric ions within the benedict’s solution.
c)
reduces the cupric ions to cuprous ions within the benedict’s solution.
d)
reduces the cuprous ions to cupric ions within the benedict’s solution.
15.
Deoxyribose is a pentose sugar that forms one of the basic structural component of DNA molecule. What is the basic difference between the ribose and deoxyribose moieties?
a)
Deoxyribose ribose is known to contain one or more oxygen atoms lesser compared to that of ribose.
b)
The OH group present at the second carbon of ribose is substituted with hydrogen in case of deoxyribose.
c)
Deoxyribose contains one oxygen atom less compared to the ribose as an oxygen moiety is removed from deoxyribose at its carbonyl group.
d)
Deoxyribose contains one oxygen atom less compared to the ribose as an oxygen moiety is removed from deoxyribose at any of its multiple hydroxyl group.
16.
Maltose and trehalose are disaccharides composed of two monomeric glucose units. Yet they are two different disaccharides having same chemical formula but having different physical and chemical properties. What could possibly be the difference among the two given disaccharides made up of glucose units only?
a)
The molecules of maltose and trehalose interact differently with water leading to all the difference between them.
b)
Maltose is always associated with protein molecules and rarely occurs singularly unlike trehalose, making it different from trehalose.
c)
The association among or between the disaccharide molecules of maltose and trehalose is different and results in all the difference between the two molecules.
d)
Difference between the carbon atoms involved in glycosidic linkage between the monosaccharide units in maltose and trehalose makes them different from each other.
17.
Starch, glycogen and cellulose are all polymers of glucose, yet enzyme cellulase is able to digest or breakdown only cellulose but not starch and glycogen. Why is it so?
a)
Because cellulose is soluble in water but starch and glycogen are not.
b)
Because cellulose is insoluble in water but starch and glycogen are soluble in water.
c)
Because cellulose is a straight and extended molecule but molecules of starch and glycogen are highly branched and coiled up.
d)
Because cellulose has different type of glycosidic bond present between the monomeric glucose units compared to starch and glycogen.
18.
Compounds that are amphipathic:
a)
repel water.
b)
are attracted towards water.
c)
partially attracted and partially repelled away from water.
d)
neither attracted towards water nor repelled away from it
19.
Which of the following are not epimers?
a)
D-mannose and D- galactose
b)
D-glucose and D-galactose
c)
D-glucose and D- mannose
d)
none
20.
Which of the following monosaccharides occur in optically active isomeric forms?
a)
Glyceraldehyde
b)
Dihydroxyacetoe
c)
Glucose
d)
Fructose
21.
Choose a correct statement:
a)
All reducing sugar undergo mutarotation in aqueous solution
b)
Sucrose is a reducing sugar
c)
Trehalose is a reducing sugar
d)
Reducing sugars are not capable of reducing Cupric ions
22.
A molecule of amylopectin consists of 1000 glucose residues and is branched every 25 residues. How many reducing ends does it have?
a)
2
b)
25
c)
1
d)
none
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