Interview MCQ Set 1
1. Peptidoglycan layer is present in large quantity in?
a) Gram-positive bacteria
b) Gram-negative bacteria
Answer: a [Reason:] Gram-positive bacteria usually have a much greater amount of peptidoglycan in their cell walls than do Gram-negative bacteria. It may account for 50 percent or more of the dry weight of the wall of some Gram-positive species, but only about 10 percent of the wall of Gram-negative bacteria.
2. Peptidoglycan is made up of __________
b) N-acetylmuramic acid
c) N-acetylglucosamine, N-acetylmuramic acid
d) N-acetylglucosamine,N-acetylmuramic acid,amino acids
Answer: d [Reason:] Peptidoglycan differs somewhat in composition and structure from one species to another,but it is basically a polymer of N-acetylglucosamine,N-acetylmuramic acid,Amino acids like-L-alanine,D-alanine,D-glutamate and a diamino acid.
3. Teichoic acid present in Gram-positive bacteria can bind to which ion?
a) Fe ions
b) Phosphorus ions
c) Mg ions
d) Sulphur ions
Answer: c [Reason:] Teichoic acid bind magnesium ions and there is some evidence that they help to protect bacteria from thermal injury by providing an accessible pool of these cations for stabilization of the cytoplasmic membrane.
4. Cord factor is a ___________
b) teichoic acid derivative
c) mycolic acid derivative
Answer: c [Reason:] Cord factor (trehalose dimycolate) is a mycolic acid derivative which is toxic and plays an important role in the diseases caused by C.diphtheriae and M.tuberculosis.
5. The outer membarane of the Gram-negative cell wall is anchored to the underlying peptidoglycan by means of which of the following?
a) Braun’s Lipoprotein
Answer: a [Reason:] The outer membrane of the Gram-negative cell wall is anchored to the underlying peptidoglycan by means of Braun’s lipoproteins. The membrane is a bilayered structure consisting mainly of phospholipids,proteins and lipopolysaccharides(LPS).
6. Which among the following acts as receptors for bacteriophage attachment in Gram-negative bacteria?
b) O antigens
c) Lipid A
d) Teichoic acid
Answer: b [Reason:] The polysaccharide O antigens which extend like whiskers from the membrane surface into the surrounding medium. Many of the serological properties of Gram-negative bacteria are attributable to O antigens like they can serve as receptors for bacteriophage attachment.
7. Porins are special proteins act as channels in outer membrane of Gram-negative bacteria.
Answer: a [Reason:] The outer membrane can allow smaller molecules such as nucleosides, oligosaccharides, monosaccharides, peptides and amino acids to pass across by means of channels in special proteins called porins.
8. NAG and NAM of peptidoglycan layer is linked by _________
a) beta-(1,4) glycosidic linkage
b) alpha-(1,4) glycosidic linkage
c) alpha-(1,6) glycosidic linkage
d) beta-(1,6) glycosidic linkage
Answer: a [Reason:] N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) of peptidoglycan layer are linked by beta-(1, 4) glycosidic linkage. Each strand contains from 10 to 65 disaccharide units.
9. Gram-negative bacteria are more resistant to antibiotics due to the presence of?
a) Thin peptidoglycan wall
b) Outer lipopolysaccharide layer
c) Porin proteins
d) Teichoic acid
Answer: b [Reason:] Gram-negative bacteria consists of an outer membrane made up of lipopolysaccharides beneath the thin peptidoglycan layer. The outer membrane serves as a barrier to various external chemicals and enzymes that could damage the cell. It also protects the bacteria from antibiotics.
10. Which of the following are present in teichoic acids?
a) ribitol residues
b) glycerol residues
c) glucose residues
d) ribitol or glycerol residues
Answer: d [Reason:] The teichoic acids are water soluble polymers,containing ribitol or glycerol residues joined through phosphodiester linkages. The glycerol or ribitol is joined to a sugar residue such as glucose, galactose or N-acetyl glucosamine.
11. Bayer’s junctions are sites which help in joining which of the following?
a) cytoplasmic membrane and outer membrane
b) outer membrane and capsule
c) cytoplasmic membrane and periplasmic space
d) peptidoglycan layer and cytoplasmic membrane
Answer: a [Reason:] The cytoplasmic membrane and outer membrane are joined at sites termed Bayer’s junctions.In these regions, the outer surface of the cytoplasmic membrane is continuous with the inner surface of the outer membrane creating pores that vary in diameter from 25 to 50 nm.
Interview MCQ Set 2
1. Chlorophyll d is present in the members of _____________________
Answer: c [Reason:] Chlorophyll d is present only in the members of Rhodophycophyta.There are five chlorophylls a,b,c,d,e which are found in different organisms.
2. Fucoxanthin pigment is present in _______________
Answer: c [Reason:] Fucoxanthin is present in Phaeophycophyta and gives it its characteristic colour brown.Other pigments like carotene and chlorophyll a and c are also present alongwith fucoxanthin.
3. Phycoerythrin pigment is present in which algal division?
Answer: b [Reason:] Phycoerythrin and phycocyanin are biloproteins present in Rhodophycophyta.They are also present in cryptomonads.
4. Chrysolaminarin is the reserved food of ___________________
Answer: c [Reason:] Chrysolaminarin is the reserved food of Xanthophycophyta which is the yellow-green algae alongwith oils.
5. Cell walls of diatoms are impregnated with _____________
Answer: d [Reason:] Cell walls of diatoms are impregnated with silica, making them thick and very rigid; they are often delicately sculptured with intricate designs characteristic of the species or variety.
6. Chloroplasts of algae embedded in the midst of the cytoplasm is known as ________________
Answer: b [Reason:] The chloroplasts may be massive structures situated near the wall which are known as parietal or embedded in the midst of the cytoplasm which are known as asteroidal.
7. Carotenes are oxygenated derivatives of hydrocarbons.
Answer: b [Reason:] Carotenes are linear,unsaturated hydrocarbons, and xanthophylls are oxygenated derivatives of these.
8. Two lateral flagella are present in which of the following groups of algae?
Answer: c [Reason:] Phaeophycophyta or the brown algae consists of two lateral flagella.Dinoflagellate or cryptomonads also consists of two lateral flagella.
9. Gullet is present in which algae?
b) Golden algae
d) Green algae
Answer: a [Reason:] Euglenoids or Euglenophycophyta contains gullet which is anteriorly present.It contains 1,2 or 3 equal or slightly apical flagella.
10. Which of the following are water-soluble pigments?
Answer: b [Reason:] Biloproteins or phycobilins are water-soluble pigments whereas chlorophylls and carotenoids are lipid-soluble.
Interview MCQ Set 3
1. Carpogonia is the female sex organ in which of the algae?
Answer: a [Reason:] Rhodophycophyta reproduce sexually heterogamously by the union of well-differentiated nonmotile male and female germ cells, the spermatia and carpogonia (female sex organs), respectively.
2.The xanthophyte walls are typically of _____________________
c) cellulose and pectin
Answer: c [Reason:] The xanthophye walls are typically of cellulose and pectin.The cellular storage product is an oil or (a branched glucan) chrysolaminarin.
3. Vaucheria is a single-celled organism.
Answer: b [Reason:] Vaucheria has a very large macroscopic filamentous form.It is widely distributed on moist soil and water.
4. Chrysamoeba exists in which of the following forms?
a) nonmotile coccoid
d) motile amoeboid
Answer: d [Reason:] Chrysamoeba is a strongly amoeboid genus with flagella.It belongs to the group of golden algae.
5. Kelps are which of the following type of algae?
a) red algae
b) yellow algae
c) brown algae
d) green algae
Answer: c [Reason:] Brown algae are structurally quite complex and kelps belong to this group.Kelps are large,the individual plants reaching a length of several hundred feet.
6. Frustules are found in which of the following algae?
Answer: a [Reason:] Bacillariophycophyta or diatoms produce shells (cell walls) containing silica, some of which are very beautiful.Shells of diatoms are called frustules.
7. Euglena contains cell wall made up of cellulose.
Answer: b [Reason:] Euglena has no cell wall containing cellulose.The outer membrane is an organized periplast.
8. Which of the following are formed in pyrenoids?
Answer: c [Reason:] The chloroplasts of green algae often contain dense regions called pyrenoids, on which surface starch granules are formed.
9.In Chlamydomonas the most common method of sexual reproduction is ________________
d) spore formation
Answer: a [Reason:] Sexua reproduction occurs in many species of Chlamydomonas, by isogamy, heterogamy, or oogamy in which isogamy is by far the most common.The zygote divides to form four or eight motile haploid cells are released.
10. Which of the following is a colonial green alga?
Answer: c [Reason:] Volvox is a colonial green alga which may form water blooms.Its colonies are visible to the naked eye.
Interview MCQ Set 4
1. In the fungal classification system Ascomycetes come under the division of ________________
Answer: c [Reason:] The class of Ascomycetes comes under the division of Amastigomycota which are terrestrial fungi.
2. Rhizopus stolonifer belongs to which class?
Answer: b [Reason:] Rhizopus stolonifer belongs to the class Zygomycetes and division Amastigomycota.
3. Which class of fungi among the following have motile cells with two laterally inserted flagella,one tinsel and the other whiplash?
Answer: d [Reason:] The Oomycetes class have motile cells with two laterally inserted flagella,one tinsel and anteriorly directed, the other whiplash and posteriorly directed.
4. Which division of fungi lack flagella?
Answer: b [Reason:] The division Amastigomycota or terrestrial fungi lack flagella.Mainly sexual spores are produced by the organisms of this division.
5.Fruiting bodies of slime moulds are called ______________
Answer: b [Reason:] Fruiting bodies of slime moulds are called sori that are masses of spores.
6. The taxa having the ending -mycetes is _______________
Answer: c [Reason:] Class have the ending -mycetes.Division have the ending -mycota, subdivision ends with -mycotina whereas order ends with -ales.
7. The common yeast Schizosaccharomyces follows which of the following asexual reproduction methods?
a) binary fission
d) spore formation
Answer: a [Reason:] In Schizosaccharomyces, asexual reproduction is by binary fission.Sexual reproduction is by conjugation of compatible cells with the subsequent formation of ascospores.
8. The structure which contains the zygote nuclei in Rhizopus stolonifer is is known as _______________
c) suspensor cell
Answer: d [Reason:] The walls of the two contacting gametangia dissolve at the point of contact, the two protoplasts mix and the + and – nuclei fuse to form many zygote nuclei.The structure which contains them is called the coenozygote.
9. The mature zygospore lies dormant for how many days?
a) 4-5 days
b) 1-3 months
c) 1 year
d) 20 days
Answer: b [Reason:] The wall around the coenozygote thickens and its surface becomes black and warty, forming the mature zygospore, which lies dormant for 1 to 3 or more months.
10. Which of the following are acellular slime moulds?
Answer: b [Reason:] Myxomycetes are acellular slime molds whose vegetative phase consists of a multicellular, wall-less plasmodium, which transforms into highly organized sporangia bearing sporangiospores.
Interview MCQ Set 5
1. How many dsRNA segments are present in the reovirus genome?
Answer: d [Reason:] Reoviruses contain both the + and the — strands of dsRNA and its genome consists of 10 dsRNA segments. During uncoating ten mRNA molecules are transcribed from one strand of the dsRNA and pass into the host cell cytoplasm.
2. Enterovirus belongs to which of the following family of viruses?
Answer: b [Reason:] Enterovirus belongs to the family Picornaviridae and it has a virion size of 28 nm.
3. Rous sarcoma virus consists of RNA as its genetic material.
Answer: a [Reason:] Rous sarcoma virus belongs to Retroviridae family, has a virion size of 100-120.It possesses icosahedral symmetry and consists of RNA as its genetic material.
4. Which of the following viruses possess an envelope?
c) Tobacco mosaic virus
Answer: a [Reason:] Herpesvirus possesses an icosahedral symmetry and contains DNA as its genetic material.Its nucleocapsid is surrounded by an envelope.
5. Which of the following viruses have a complex symmetry?
Answer: c [Reason:] Orthopoxvirus posseses a complex symmetry and is surrounded by a coat.It consists of DNA as its nucleic acid.
6. The family of Rhabdoviridae possesses dsRNA.
Answer: b [Reason:] The family of Rhabdoviridae consists of ssRNA and they are enveloped.An example is vesicular stomatitis.
7. Cowpea virus belongs to which of the following group of viruses?
Answer: a [Reason:] Cowpea mosaic belongs to the Comovirus group of viruses.They are non-enveloped and possess ssRNA.
8. For the cultivation of viruses the fertile chicken eggs should be incubated for how many day(s)?
Answer: c [Reason:] For cultivation of viruses by embryonated chicken eggs, the fertile chicken eggs should be incubated for 5 to 12 days and then they can be inoculated through the shell aseptically.
9. Which of the following method is used for the production of vaccines against yellow fever?
a) tissue-culture method
b) chick-embryo method
c) through susceptible animals
d) through appropriate media
Answer: b [Reason:] The chick-embryo technique has been used in the production of vaccines against smallpox, yellow fever, influenza, and other diseases and in immunologic tests and other studies whenever large amounts of virus are required.
10. The karyotype of cells formed from continuous cell lines is _______________
d) haploid and diploid
Answer: c [Reason:] The karyotype of cells cultured through continuous cell lines is aneuploid i.e., a variable multiple of the haploid chromosome number and not diploid.