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BIO CHEM 3 Flashcards

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1
Q

The allosteric inhibitor of an enzymE

Causes the enzyme to work faster
Binds to the active site
Participates in feedback regulation
Denatures the enzyme

A

Participates in feedback regulation

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2
Q

Which of the following is false about allosteric feedback inhibition?

Bacterial enzyme system is the first known example

Conversion of L-leucine to L-isoleucine

Threonine dehydratase is inhibited by isoleucine

If the isoleucine concentration decreases, the rate of threonine dehydration increases

A

Conversion of L-leucine to L-isoleucine

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3
Q

Which of the following is false?

Methyl, phosphoryl, adenyl, uridylyl and adenosine diphosphate ribosyl groups are the modifying groups

An example of an enzyme regulated by methylation is the methyl-donating chemo taxis protein of bacteria

The protein is a part of the system that permits a bacterium to swim towards attractant

The methylating agent is S- adenosylmethionine

A

An example of an enzyme regulated by methylation is the methyl-donating chemo taxis protein of bacteria

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4
Q

Which of the following enzyme is responsible for the regulation of biological nitrogen fixation?

Dinitrogenase reductase
Dinitrogenase oxidase
Phosphatase
Kinase

A

Dinitrogenase reductase

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5
Q

Which of the following enzymes catalyze the ADP-ribosylation of key cellular enzymes or proteins?

Diphteria toxin and cholera toxin
Dinitrogenase reductase
Protein phosphatases
Kinase

A

Diphteria toxin and cholera toxin

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6
Q

Removal of phosphoryl groups is catalyzed by

Diphteria toxin and cholera toxin
Dinitrogenase reductase
Protein phosphatases
Protein kinases

A

Protein phosphatases

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7
Q

The attachment of phosphoryl groups to specific amino acid residues is catalyzed by

Diphteria toxin and cholera toxin
Dinitrogenase reductase
Protein phosphatases
Protein kinases

A

Protein kinases

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8
Q

Phosphorylase a +2H2O → phosphorylase b + 2Pi
Which of the following is false about this reaction?

Phosphorylase a is less active and phosphorylase b is more active

Glycogen phosphorylase catalyzes this reaction

Phosphorylase b can be transformed back into phosphorylase a by phosphorylase kinase

Phosphorylase kinase catalyzes the transfer of phosphoryl groups from ATP to Phosphorylase b

A

Phosphorylase a is less active and phosphorylase b is more active

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9
Q

Which of the following takes place due to phosphorylation of isocitrate dehydrogenase?

Inhibits the binding of citrate at active site
Degrades the enzyme
Enhances the substrate-binding affinity
No reaction

A

Inhibits the binding of citrate at active site

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10
Q

Which of the following enzyme catalyzes a reaction that introduces reduced nitrogen ito cellular metabolism?

Bacterial glutamine synthase
Bacterial dinitrogenase reductase
Bacterial dinitrogenase oxidase
Phosphatase

A

Bacterial glutamine synthase

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11
Q
  1. Which of the following is false about feedback regulation?

It is a type of enzymatic activity regulation

The synthesis of concerned enzyme is inhibited by interfering with the gene of that enzyme

Concentration of enzyme is reduced by the end product

The best example is the biosynthesis of L-isoleucine from L-threonine in bacteria

A

NO ANSWER, PLEASE CHECK OTHER REFERENCE

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12
Q

Which of the following is false?

Allosteric modulators may be inhibitory or stimulatory

Based on the nature of modulator, allosteric enzymes are of two types

Homotropic allosteric enzymes have the substrate and modulator same

Heterotropic allosteric enzymes have the substrate and modulator same

A

Heterotropic allosteric enzymes have the substrate and modulator same

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13
Q

In the case of allosteric enzymes what is the graphical representation when initial velocity is plotted against substrate concentration?

Straight line with negative slope
Hyperbola
Sigmoid curve
Parabola

A

Sigmoid curve

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14
Q

How many types of enzymatic regulation mechanism occurs in the cells?

2
3
4
5

A

5

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15
Q

Which is the enzyme that acts as a regulatory enzyme in a four-step metabolic pathway?

First enzyme
Fourth enzyme
Second enzyme
Third enzyme

A

First enzyme

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16
Q

Anthrone method is preferred in the determination of

Carbohydrates
Proteins
Vitamins
Fats

A

Carbohydrates

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17
Q

Which of the following are an example of epimers?

Glucose & Galactose
Glucose & Ribose
Mannose & Glucose
a & c

A

Glucose & Galactose

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18
Q

One of the following has reducing properties

Glucuronic acid
Gluconic acid
Glucaric acid
Mucic acid

A

Glucuronic acid

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19
Q

The red precipitate formed when glucose is heated with “Benedict’s reagent” is

Cupric hydroxide
Cuprous hydroxide
Cupric oxide
Cuprous oxide

A

Cuprous oxide

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20
Q

Fructose and Glucose can be distinguished by

Selwinoff’s reagent
Benedict’s reagent
Fehling’s reagent
Barfoed’s reagent

A

Selwinoff’s reagent

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21
Q

Which of the following is an example of monosaccharide?

Galactose
Sucrose
Lactose
Maltose

A

Galactose

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22
Q

Which of the following is an example of disaccharide?

Glucose
Fructose
Galactose
Maltose

A

Maltose

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23
Q

In maltose, between which of the following carbons there is a linkage?

C1, C2
C2, C3
C1, C4
C2, C4

A

C1, C4

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24
Q

Which of the following carbohydrates is a triose?

Glucose
Ribose
Ribulose
Glyceraldehyde

A

Glyceraldehyde

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25
Q

Lactose is a disaccharide of which of the following sugar units?

Glucose and fructose
Glucose and galactose
Glucose and sucrose
Glucose and ribose

A

Glucose and galactose

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26
Q

Which of the following is an example of bacterial and yeast polysaccharide?

Starch
Glycogen
Cellulose
Dextrans

A

Dextrans

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27
Q

In which of the following, glucose residues are linked by β1 - 4 glycosidic bonds?

Amylose
Starch
Cellulose
Glycogen

A

Cellulose

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28
Q

What is the chemical difference between cellulose and chitin?

Replacement of the hydroxyl group at C2 with an acetylated amino group

Replacement of the hydroxyl group at C3 with an acetylated amino group

Replacement of the hydroxyl group at C4 with an acetylated amino group

Replacement of the hydroxyl group at C5 with an acetylated amino group

A

Replacement of the hydroxyl group at C2 with an acetylated amino group

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29
Q

When all the monosaccharides in a polysaccharide are same type, such type of a polysaccharide is called a

Glycogen
Homoglycan
Heteroglycan
Oligosaccharide

A

Homoglycan

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30
Q

In which of the following forms, glucose is stored in plants?

Glycogen
Starch
Dextrin
Cellulose

A

Starch

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31
Q

In which of the following forms, glucose is stored in liver?

Glycogen
Starch
Dextrin
Cellulose

A

Glycogen

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32
Q

Which of the following are the storage polysaccharides?

Glycogen
Cellulose
Chitin
Glucose

A

Glycogen

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33
Q

Which of the following are the structural polysaccharides?

Glycogen
Starch
Chitin
Glucose

A

Chitin

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34
Q

Which of the following is an analogous to starch?

Cellulose
Glycogen
Sucrose
Chitin

A

Glycogen

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35
Q

Which of the following is not a monosaccharide with 5 carbon atoms?

Arabinose
Xylulose
Trehalose
Ribulose

A

Trehalose

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36
Q

Which of the following are found in connective tissues?

Glycosamineglycans
Proteoglycans
Gycoproteins
Glycolipids

A

Proteoglycans

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37
Q

Which of the following statements is false about proteoglacans?

They hold less amount of water
Chondroitin sulfate is a proteoglycan
They possess charge
They are made of amino acids and sugars

A

They hold less amount of water

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38
Q

In cell membrane, carbohydrates in glycoproteins or glycolipids are oriented?

Towards outside
Towards inside
Towards outside and inside
Randomly distributed

A

Towards outside

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39
Q

Which of the following is an oligosaccharide linked to protein?

Glycolipid
Glycoprotein
Ganglioside
Galactoside

A

Glycolipid

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40
Q

The protein core of proteoglycan is rich in

Serine and threonine
Serine and methionine
Threonine and methionine
Alanine and serine

A

Serine and threonine

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41
Q

Which of the following are included in the types of glycolipids?

N-acetylgalactosamine
N-acetylglucosamine
Xylose
Cerebrosides

A

Cerebrosides

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42
Q

Which of the following blood group individuals have N-acetylgalactosamine sugar attachment?

A
B
AB
O

A

A

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43
Q

Which of the following blood group individuals have galactose ?

A
B
AB
O

A

B

44
Q

Which of the following glycoprotein functions as a lubricant and protective agent?

Collagens
Mucins
Transferrins
Immunoglobulins

A

Mucins

45
Q

Which of the following are important for white blood cell recognition?

Glycosamineglycans
Proteoglycans
Gycoproteins
Glycolipids

A

Gycoproteins

46
Q

Identify the purine base of nucleic acids in the following

Cytosine
Thymine
Uracil
Adenine

A

Adenine

47
Q

Which of the following are not the components of RNA?

Thymine
Adenine
Guanine
Cytosine

A

Thymine

48
Q

Which of the following statements is true?

Sugar component of a nucleotide is ribose

Sugar component of a nucleotide is deoxyribose

The bases in nucleotides are attached to a pentose sugar moiety by a glycosidic linkage

The sugar molecule of the nucleotide is in L-configuration

A

The bases in nucleotides are attached to a pentose sugar moiety by a glycosidic linkage

49
Q

What is the composition of nucleoside?

a sugar + a phosphate
a base + a sugar
a base + a phosphate
a base + a sugar + phosphate

A

a base + a sugar

50
Q

What is the composition of nucleotide?

a sugar + a phosphate
a base + a sugar
a base + a phosphate
a base + a sugar + phosphate

A

a base + a sugar + phosphate

51
Q

Group of adjacent nucleotides are joined by

Phosphodiester bond
Peptide bond
Ionic bond
Covalent bond

A

Phosphodiester bond

52
Q

The sugar molecule in a nucleotide is

Pentose
Hexose
Tetrose
Triose

A

Pentose

53
Q

Which of the following is true about phosphodiester linkage?

5’-phosphate group of one nucleotide unit is joined to the 3’-hydroxyl group of the next nucleotide

3’-phosphate group of one nucleotide unit is joined to the 5’-hydroxyl group of the next nucleotide

5’-phosphate group of one nucleotide unit is joined to the 5’-hydroxyl group of the next nucleotide

3’-phosphate group of one nucleotide unit is joined to the 3’-hydroxyl group of the next nucleotide

A

5’-phosphate group of one nucleotide unit is joined to the 3’-hydroxyl group of the next nucleotide

54
Q

Which of the following is false about purine and pyrimidine bases?

They are hydrophobic and relatively insoluble in water at the near-neutral pH of the cell

At acidic or alkaline pH the bases become charged and their solubility in water increases

Purines have two rings in their structure, but pyrimidine bases have only one ring

At acidic or alkaline pH the bases become charged and their solubility in water decreases

A

At acidic or alkaline pH the bases become charged and their solubility in water decreases

55
Q

Building blocks of nucleic acids are

Nucleotides
Nucleosides
Amino acids
Histones

A

Nucleotides

56
Q

Number of hydrogen bonds between adenine and thymine?

1
2
3
4

A

2

57
Q

Number of hydrogen bonds between guanine and cytosine?

1
2
3
4

A

3

58
Q

Which ratio is constant for DNA?

A + G / T + C
A + T / G + C
A + C / U + G
A + U / G + C

A

A + G / T + C

59
Q

According to Chargaff’s rule, in a DNA molecule

The amount of adenine and thymine is equal to the amount of guanine and cytosine

The amount of adenine and guanine is equal to the amount of thymine and cytosine

The amount of adenine and uracil is equal to the amount of guanine and cytosine

The amount of adenine and guanine is equal to the amount of uracil and cytosine

A

The amount of adenine and thymine is equal to the amount of guanine and cytosine

60
Q

Arrangement of nucleotides in DNA can be seen by

Ultracentrifuge
X-Ray crystallography
Light microscope
Electron microscope

A

X-Ray crystallography

61
Q

Which of the following leads to disruption of nucleosomal structure?

Acetylation
Carboxylation
Phosphorylation
Methylation

A

Methylation

62
Q

One of the following nucleic acids has a left handed helix

M-RNA
T-RNA
A-DNA
Z-DNA

A

Z-DNA

63
Q

Which of the following statements is not true about RNA?

Does not have a double stranded structure
Thymine is present
Does not obey Chargaff’s rule
The sugar contained in RNA is a ribose

A

Thymine is present

64
Q

Which of the following is true about Z-DNA helix?

It has alternating GC sequences
It is a permanent conformation of DNA
It tends to be found at the 3’ end of the genes
It has fewer base pairs per turn than B-DNA

A

It has alternating GC sequences

65
Q

Which of the following statements is true?

The template strand matches the sequence of the RNA transcript

The two strands of DNA run parallel to each other

G-C bonds are much more resistant to denaturation than A-T rich regions

The common form of DNA is left handed

A

G-C bonds are much more resistant to denaturation than A-T rich regions

66
Q

What happens in hypochromicity?

When DNA is in bound form, there is decrease in absorption of UV light

When DNA is in bound form, there is increase in absorption of UV light

When DNA is in unbound form, it is more stable

When DNA is in unbound form, there is decrease in absorption of UV light

A

When DNA is in bound form, there is decrease in absorption of UV light

67
Q

What happens in hyperchromicity?

When DNA is in bound form, there is decrease in absorption of UV light

When DNA is in bound form, there is increase in absorption of UV light

When DNA is in unbound form, it is more stable

When DNA is in unbound form, there is increase in absorption of UV light

A

When DNA is in unbound form, there is increase in absorption of UV light

68
Q

Which of the following is true about tm?

It can be termed as renaturation temperature

The higher the content of G ≡ C base pairs, the higher the tm

The higher the content of A = T base pairs, the higher the tm

The higher the content of G ≡ C base pairs, the lower the tm

A

The higher the content of G ≡ C base pairs, the higher the tm

69
Q

Which of the following is false?

The stability of an RNA-DNA hybrid is generally intermediate between that of RNA and DNA

RNA duplexes are more stable than DNA duplexes

DNA duplexes are more stable than RNA duplexes

DNA duplexes are less stable than RNA- DNA hybrid

A

DNA duplexes are more stable than RNA duplexes

70
Q

DNA denaturation is measured by absorbance at

220nm
230nm
250nm
260nm

A

260nm

71
Q

Which of the following is false about denaturation?

Disruption of hydrogen bonds

Disruption of phosphodiester linkage

Loss of helical structure of DNA

It is resulted as a result of change in pH or increase in temperature

A

Disruption of phosphodiester linkage

72
Q

Which of the following nucleotides is not present in RNA?

AMP
GMP
CMP
TMP

A

TMP

73
Q

Which of the following nucleotides is not present in DNA?

AMP
GMP
CMP
UMP

A

UMP

74
Q

Which of the following is false?

RNA does not obey Chargaff’s rule
DNAs can be identified by Orcinol color reaction
In RNA OH group is present at 2’ position
Alkali hydrolyses RNA to 2’3’-cyclic diesters

A

DNAs can be identified by Orcinol color reaction

75
Q

Which of the following involves in carrying genetic information from DNA for protein synthesis?

m-RNA
t-RNA
r-RNA
sn-RNA

A

m-RNA

76
Q

Which of the following does not act as a restriction enzyme?

EcorI
BamHI
HindIII
polydeoxyribonucleotide synthase

A

polydeoxyribonucleotide synthase

77
Q

Which of the following enzyme is responsible for making a DNA copy from RNA?

Reverse transcriptase
DNA polymerase
RNA polI
RNA polII

A

Reverse transcriptase

78
Q

Which of the following statements is true?

Exonuclease III removes nucleotide residues from the 3’ ends of a DNA strand

Bacteriophage lambda exonuclease removes terminal phosphates

Alkaline phosphatase removes nucleotides from 5‘ends

Kinase adds homopolymer tails to the 3’ –OH ends of a linear duplex

A

Exonuclease III removes nucleotide residues from the 3’ ends of a DNA strand

79
Q

Which of the following can be termed as a restriction modification system?

Restriction endonuclease + methylase
DNA ligase + methylase
Restriction endonuclease + acetylase
DNA ligase + acetylase

A

a. Restriction endonuclease + methylase

80
Q

Which of the following is true about restriction endonucleases?

Type I and II requires ATP to move along DNA

Type I, II and III requires ATP to move along DNA

Type II requires no ATP and cleaves DNA within recognition sequence

Type II requires ATP and cleaves DNA within recognition sequence

A

Type II requires no ATP and cleaves DNA within recognition sequence

81
Q

Which of the following enzymes’ combined action leads to the generation of sticky ends in plasmid vector?

Alkaline phosphatase and terminal transferase

Exonuclease III and alkaline phosphatase

Bacteriophage lambda exonuclease and terminal
transferase

Exonuclease III and terminal transferase

A

Bacteriophage lambda exonuclease and terminal

transferase

82
Q

Generally a plasmid vector contains how many elements?

1
2
3
4

A

3

83
Q

To make the recombinant plasmid permeable to DNA molecules, which of the chemicals is added?

MgCl2
CaCl2
NaCl
HCl

A

CaCl2

84
Q

Which of the following statements is false?

The cells which take up recombinant plasmids are drug resistant

The cells with no recombinant plasmids are drug resistant

Plasmid replication is independent of cell’s division

The cells containing recombinant plasmid are called transformed cells

A

The cells which take up recombinant plasmids are drug resistant

85
Q

The extra chromosomal, self-replicating, closed, double stranded and circular DNA molecule is generally termed as

Chromosome
Plasmid
Genomic DNA
Bacteriophage

A

Plasmid

86
Q

E.cor1 is a

DNA ligase enzyme
Restriction endonuclease
A vector used for insulin synthesis
A plasmid used as a vector

A

Restriction endonuclease

87
Q

In which stage of genetic engineering a probe is used?

Cleaving DNA
Recombining DNA
Cloning
Screening

A

Screening

88
Q

A DNA library is a

A DNA fragment inserted into a vector.

A general collection of all genes sequenced thus far.

All DNA fragments identified with a probe.

A collection of DNA fragments that make up the entire genome of a particular organism.

A

A collection of DNA fragments that make up the entire genome of a particular organism.

89
Q

Which of the following enzyme is required for end to end joining of DNA?

DNA ligase
Restriction endonuclease
RNA polymerase
DNA polymerase

A

DNA ligase

90
Q

Repressor molecules bind to

Operator
Promoter
Enhancer
Hormone response element

A

Operator

91
Q

Generally YAC contains how many elements?

1
2
3
4

A

4

92
Q

Which of the following endonuclease removes a length of DNA between two telomere sequences?

EcoR1
EcoR2
BamHI
HindIII

A

BamHI

93
Q

In hybridization method, which of the following is pressed onto agar?

Silicon paper
Nitrocellulose paper
Filter paper
PVDF

A

Nitrocellulose paper

94
Q

Which of the following temperature best suits for the growth and multiplication of transformed cells?

35°C
36°C
37°C
30°C

A

37°C

95
Q

Which of the following is a DNA element that instructs RNA polymerase where to bind on DNA?

Operator
Promoter
Enhancer
Hormone response element

A

Promoter

96
Q

Site directed mutagenesis facilitated research on

Carbohydrates
Proteins
Lipids
Fats

A

Proteins

97
Q

Recombinant DNA molecule is produced by ligating

Two DNA segments
Two m-RNA molecules
One m-RNA with one t-RNA
One m-RNA with DNA segment

A

Two DNA segments

98
Q

Arrange the following steps involved in Gene cloning in the correct order

i. Isolation of desired gene
ii. Insertion of isolated gene to the vector
iii. Introduction of recombinant vector to the host
iv. Expression of recombinant gene in host
v. Extraction of recombinant gene product

i, ii, iii, iv, v
v, iv, iii, ii, i
i, iii, ii, iv, v
iv, v, ii, i, iii

A

i, ii, iii, iv, v

99
Q

Where does a restriction endonuclease cuts DNA?

Ligation site
Recognition sequence
Ori
Replication site

A

Recognition sequence

100
Q

Which of the following statements is true about a vector?

Plasmids, phages can be used as vectors
All vectors are plasmids
Cyanobacteria can also be used as vectors
Fungi can also be used as vectors

A

Plasmids, phages can be used as vectors

101
Q

Which of the following is true about plasmids?

They are present in all organisms
They are present in bacteria only
They are present in bacteria and phages
They are present in plants and animals

A

They are present in bacteria and phages

102
Q

DNA Ligase, used in recombinant DNA technology is obtained from

E.coli only
E.coli and also Ligase encoded by T4 phage
Saccharomyces
Retroviruses

A

E.coli and also Ligase encoded by T4 phage

103
Q

The main aim of human genome project is

To identify and sequence of all the genes present in the human body

To introduce new genes to human beings

To remove disease causing genes from humans

To improve techniques of finger printing

A

To identify and sequence of all the genes present in the human body

104
Q

The work ‘Hybridization’ in DNA finger printing means

Pairing between the nucleotides of DNA sample with probe

Pairing between the nucleotides of DNA and mRNA

Pairing between the nucleotides of probe with mRNA

Pairing between the nucleosides with mRNA

A

Pairing between the nucleotides of DNA sample with probe

105
Q

Agar is extracted from

Fungi
Bacteria
Algae
Virus

A

Algae

106
Q

END

A

END

BIO CHEM (10 decks)

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