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Bacteria: types and structure - class-XI

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Hens egg is

  1. An organ

  2. A single cell

  3. A tissue

  4. None of the above


Correct Option: B
Explanation:

Hens egg is a single cell structure inside the shell before the fertilization that can be seen by naked eyes. But after fertilization, the cells fused and divide into two cells inside the shell.

Hence, option B is correct.

A bacteria attaches to the host cell with the help of bristle-like structure is called

  1. Pili

  2. Flagella

  3. Fimbriae

  4. Cell wall


Correct Option: A

Which one of the following is an example of unicellular organism?

  1. Paramecium

  2. Frog

  3. Snake

  4. Bird


Correct Option: A
Explanation:
The cell is the structural unit of life. Unicellular organisms are made up of one cell that performs all the functions. Example of unicellular organisms are bacteria, yeast, protozoa. Paramecium belongs to protozoa. Thus, the correct answer is option A.

Which one of the following is the example of unicellular organism?

  1. Snake

  2. Yeast

  3. Bird

  4. Shark


Correct Option: B
Explanation:

The cell is the structural unit of life. Unicellular organisms are made up of one cell that performs all the functions, unlike a multicellular organism that consists of multiple cells e.g., yeast, bacteria. Thus, the correct answer is option B.

Amoeba is said to be a ...........organism. 

  1. Organized

  2. Multi-cellular

  3. Unicellular

  4. Well defined


Correct Option: C
Explanation:
Amoeba is a unicellular eukaryote. It is made up of a single cell which carries out all functions like movement, respiration, excretion etc. 
Therefore the correct answer is option C.

True nucleus is absent in

  1. Green algae

  2. Fungi

  3. Lichens

  4. Bacteria


Correct Option: D
Explanation:

Bacteria are prokaryotes grouped in Kingdom Monera. Prokaryotes have a pro or primitive karyon. Thus the true nucleus is absent in bacteria. The chromosome, a single, continuous strand of DNA, is localized, but not contained, in a region of the cell called the nucleoid. All the other cellular components are scattered throughout the cytoplasm.

Bacteria are made up of

  1. Nucleic acid

  2. Only proteins

  3. Nucleic acid and Proteins

  4. Nucleosides

  5. None of these


Correct Option: C
Explanation:

Nucleic acids constitute the genetic material and help in cellular expressions in bacteria, while proteins are important for constitutive activities in the bacterial cells. 15% of bacterial cell is protein, while 7% nucleic acids (DNA and RNA).
So answer is -'nucleic acid and proteins'.

A unicellular organism has

  1. just one cell

  2. many cells

  3. few cells

  4. no cells


Correct Option: A
Explanation:

An organism made of just one cell is called an unicellular organism. Bacteria, Amoeba,  Paramoecium and Euglena are some examples of unicellular organisms.

Which of the following is the location of mucilage capsule present in bacteria which serves as an extra covering?

  1. Outside the cell membrane

  2. Inside the cell membrane

  3. Outside the cell wall

  4. Inside the cell wall


Correct Option: C
Explanation:

The mucilage capsule present in bacteria serving as an extra covering is present outside the cell because it is a temporary layer surrounding the cell wall and protects the bacteria from antibiotics and dessication.

So, the correct option is C.

Lifecycle of Saccharomyces cerevisiae is 

  1. haplontic type

  2. diplontic type

  3. haplo diplobiontic type

  4. none of these


Correct Option: C
Explanation:
This type of life cycle is represented by haploid and diploid phases, of more or less equal duration, found in Saccharomyces cerevisiae. The haploid cells of opposite mating type normally multiply by budding. Two such cells of opposite mating behave as gametangia and undergo fusion initially only plasmogamy takes place, wherein the nuclei exist separately also called the dikaryotic phase. Later on the nuclei undergo fusion in specialized sac like structures called the ascus to form a diploid zygote, which undergoes meiosis to release the haploid ascospores.
So, the correct answer is 'haplodiplobiontic type'

Select the wrong statements.
A. Pyruvic acid decarboxylase and alcohol dehydrogenase catalyse fermentation.
B. $NADH+H^+$ is reoxidised to $NAD^+$ in alcohol and lactic acid fermentation.
C. Yeasts poison themselves to death when the concentration of alcohol reaches about $31$ percent.
D. Prolonged fermentation results greater alcohol contents in alcohol beverages.

  1. C and D

  2. A and B

  3. B and C

  4. A and D


Correct Option: A

Bacterial genome consist of 

  1. Circular, ssRNA

  2. Circular, dsDNA

  3. Linear, triple stranded DNA

  4. zig-zag DNA


Correct Option: B
Explanation:

Bacterial genome as that of a bacteria E.coli consists of Double-stranded DNA (ds DNA) which is circular which means it doesn't have ends like eukaryotic chromosomes. E.coli consists of 4.6 x 10$^6$ base pairs(bp).

So, the correct answer is 'Circular, dsDNA'.

The meiospores of yeast are nonmotile and called?

  1. Aeciospores

  2. Aplanospores

  3. Ascospores

  4. Basidispores


Correct Option: A

Which of the following microtubule arrangement is absent in the kinetosome of eukaryotic flagella?

  1. 9+0

  2. 9+2

  3. Both of the above

  4. None of the above


Correct Option: B
Explanation:
  • Eukaryotic cilia and flagella have similar organization-
  • They possess a central bundle of microtubules called the axoneme which contain nine outer doublet microtubules surrounded by a central pair of singlet microtubules.
  • This characteristic 9 + 2 arrangement of microtubules is seen when the axoneme of eukaryotic flagella.
  • The correct answer is OPTION B.

The bacterial cell wall is made up of 

  1. Cellulose

  2. Hemicellulose

  3. Cellulose and hemicellulose

  4. Peptidoglycan

  5. Glycogen


Correct Option: D
Explanation:

Peptidoglycans (or mucopeptide or glycopeptide or murein) are the structural elements of almost all bacterial cell walls. They constitute as much as 95% of the cell wall in some Gram positive bacteria to as little as 5 to 10% in Gram negative bacteria. Peptidoglycans are made up of a polysaccharide backbone consisting of alternating muramic acid and glucose amine residues in equal amounts.

Match the contents of Column-I with of Column-II.

Colum-I Column-II
A Monascus purpurens i Statins
B Aspergillus niger ii Cyclosporin-A
C Trichoderma polysporum iii Citric acid
  1. A-i, B-ii, C-iii

  2. A-i, B-iii, C-ii

  3. A-iii, B-i, C-ii

  4. A-ii, B-i, C-iii


Correct Option: A

The bacteria which lacks flagella and moves by gliding are included in?

  1. Spirochetes

  2. Rickettsia

  3. Myxobacteria

  4. Eubacteria


Correct Option: A

Bacteroides are?

  1. Enlarged non-motile cellular bacteria Rhizobium leguminosarum in root nodules of legumes

  2. A bacterial cell infected with viruses

  3. A motile bacterium

  4. Nitrosomonas bacteria in soil


Correct Option: A

Membrane bound organelles are absent in 

  1. Plasmodium

  2. Saccharomyces

  3. Streptococcus

  4. Chlamydomonas


Correct Option: C
Explanation:

Membrane bound organelles are absent in prokaryotes. As compared to a eukaryotic cell, the only comparable organelles present in prokaryotes are ribosomes which are naked nucleoprotein particles. Plasmodium is a unicellular eukaryotic organism which belongs to Kingdom Protista. Saccharomyces is also a unicellular eukaryotic organism which belongs to Kingdom Mycota or Fungi. Streptococcus is a unicellular prokaryotic organism which belongs to Kingdom Monera. Chlamydomonas is a unicellular eukaryotic organism, previously classified under Kingdom Plantae as Chlorophyceae but has now been moved to Kingdom Protista. Of the given options only Streptococcus is a prokaryotic organism. Hence, membrane bound cell organelles are missing in Streptococcus.

Which of the following is common features of Amoeba?

  1. Pseudopodia, food vacuole, phagocytosis, assimilation and egestion

  2. Phagocytosis, contractile vacuole, lysosome, holozoic and ingestion

  3. Contractile vacuole, absorption of food, egestion and grinding of food particles

  4. Pseudopodia, ciliary movement, contractile vacuole and phagocytosis


Correct Option: A
Explanation:

An Amoeba is a type of organism belongs to kingdom Protista. They have the ability to alter its shape, primarily by extending and retracting pseudopods. Amoeba has contractile vacuole which expels excess water from the cell. The various processes which are involved in the nutrition of Amoeba are:
Ingestion, digestion, absorption, assimilation and egestion. Amoeba has not excretory organs. The undigested food collects inside the Amoeba is thrown out of the body by the cell membrane. Thus, the correct answer is option A.

DNA of E.coli  

  1. ds circular

  2. ss circular

  3. ds linear

  4. ss linear


Correct Option: A
Explanation:

  E. coli , a gram negative rod shaped bacteria has since the time of discovery have been commonly used for biological lab experiment and research. The simple cell structured E. coli has one circular chromosome and a ds circular DNA molecule with 4.6 million base pairs in length and 4288 protein coding genes.

Muramic acid is present in cell walls of

  1. Bacteria

  2. Green algae

  3. Yeast

  4. All fungi


Correct Option: A
Explanation:

The cell walls of bacteria are composed of a macromolecule peptidoglycan which is a repeating framework of long glycan chains having alternate N-acetyl glucosamine and N-acetyl muramic acid; these glycan chains are cross-linked by short peptide fragments to provide a strong but flexible support framework. This makes option A correct. The green algal cell wall is composed mainly of cellulose which makes option B incorrect. Chitin is common constituent of cell walls of all type of fungi; option C is incorrect. The yeast cell wall itself is mainly composed of glucans ($\beta$$-glucans), mannoproteins and chitin; option D is incorrect. Thus, the correct answer is option A.

The body of Amoeba is made up of .......... cell.

  1. Single

  2. Multiple

  3. Three

  4. Four


Correct Option: A
Explanation:

Amoeba is a protozoan belonging to the kingdom Protista. They are unicellular eukaryotic organisms and thus, made up of single cell.

Cocci that remain in chains after dividing are called ...........

  1. Diplococci

  2. Tetrococci

  3. Streptococci

  4. Sarcinae


Correct Option: C
Explanation:

Cocci that remain in pains after dividing are called diplococci. Cocci that remain in chains after dividing are called streptococci.

What are the major groups of microorganisms?

  1. Bacteria, fungi

  2. Protozoa, algae

  3. Bacteria, fungi, protozoa, algae and virus.

  4. Fungi, algae and virus


Correct Option: C
Explanation:

Microorganisms are the organisms that we cannot see by our naked eyes. It can be prokaryotic unicellular like bacteria, eukaryotic unicellular like protozoa, eukaryotic multicellular like fungi and algae and even acellular like viruses.

Thus, the correct answer is option C.

Unicellular organisms are capable of (i) Independent existence (ii) Performing the essential functions of life

  1. Only I

  2. Only II

  3. Both A and B

  4. None of the above


Correct Option: C
Explanation:

Unicellular organisms are made up of a single cell and perform all the life processes for survival and independent existence.  Hence, the cell is called as the fundamental structural and functional unit of life.

Many bacteria bear minute hairy structures on their cell wall which are involved in genetic transfer are called as

  1. Hairs

  2. Flagella

  3. Pili

  4. Cilia


Correct Option: C
Explanation:

Pili are minute hair like appendages, that emerges from suface of Gram -ve bacteria. They have similar structure as flagella and often involved in attachment to surface and making of biofilm. They also help in DNA exchange. They are involved in conjugation which results in transfer or exchange of genetic material. 

Escherichia colt has the following combination of characters.

  1. Rod shaped, 1-3$\mu $m long, gram negative

  2. Rod shaped, 1- 3$\mu $m long, gram positive

  3. Spiral, 1-3$\mu $m long, gram negative

  4. Spiral, 1-3$\mu $m long, gram positive


Correct Option: A

Binary fission in Amoeba involves ____________.

  1. Amitosis

  2. Mitosis

  3. Meiosis

  4. None of these


Correct Option: B
Explanation:

The reproduction in amoeba is asexual, called binary fission, where it replicated its cells by mitosis and its cell divide in two equal daughter cells. Amitosis is similar to binary fission. Meiosis does not take place in amoeba.

The correct answer is B. 

Torula condition' occurs in ________.

  1. Rhizopus

  2. Ulothrix

  3. Spirogyra

  4. Riccia


Correct Option: A
Explanation:
When some species of like mucor they grow in high concentrated liquid medium of sugar and they brown up into small pieces called odia and further they grow like yeast by budding and this condition called Torula condition.
Hence the correct answer is A. 

Amoeba takes food through ____________.

  1. Phagocytosis

  2. Pinocytosis

  3. Endocytosis

  4. All the above


Correct Option: D
Explanation:

Amoeba takes its food by the method of phagocytosis (i.e ingesting or engulfing the food particles), also by means of pinocytosis (wherein amoeba wraps around its membranes around the food forms vesicles and pinch it inside the membrane and then gradually digests it) and by endocytosis (in which the outermost the membrane of amoeba either stretches inwards or projects outwards to obtain nutrition.

The correct answer is D.

Which of the following is a photo-autotrophic bacterium

  1. Rhodospirillum

  2. Azospirillum

  3. NitrosomonasV

  4. Nitrobacter


Correct Option: A
Explanation:

Rhodospirillum bacteria is facultative aerobic Photo - autotrophic bacteria use non-sulphur aliphatic organic  compound as donor of $H _{2}$  go,. Propyl alcohol .

$6CO _{2}+12CH _{3}CHOHCH _{3}\overset{Light}{\rightarrow}$

$C _{6}H _{12}O _{6}+12CH _{3}COH _{3}+6H _{2}O$



In Amoeba, the cell division takes place ____

  1. Involving changes in the chromatin reticulum

  2. Without involving changes in the chromatin reticulum

  3. Leading to reduction in the number of chromosomes

  4. Without dividing the nucleus


Correct Option: A
Explanation:
Through the cell division process one cell splits into two identical cells. There can be two kind of cell divisions- Mitosis and Meiosis. Cell division mitosis takes place in Amoeba for replicating genetic material (chromatin network) into the daughter cells. It is a form of asexual reproduction in unicellular organisms like Amoeba. The process is known as binary fission.
So, the correct answer is 'Involving changes in the chromatin reticulum'

Some bacteria are considered plants as they

  1. Are green in colour

  2. Have rigid cell wall

  3. Have chlorophyll

  4. Have stomata


Correct Option: C

In bacteria the site for respiratory activity is found in

  1. Episome

  2. Microsome

  3. Ribosome

  4. Cell membrane$/$ Mesosome


Correct Option: D
Explanation:

In bacteria the site for respiratory activity is found in mesosomes. Mesosomes are folded invaginations in the cell membrane of bacteria. They increases the surface area required for respiration. They contain respiratory enzymes. It is the site of respiratory activity.

Thus, the correct answer is 'Cell membrane/ Mesosome.'

Sex factor of bacteria is

  1. RNA

  2. Sex pili

  3. F-factor

  4. Chromosome replicon


Correct Option: C
Explanation:

F-factor is also called as fertility factor. It is the sex factor of bacteria. It allows the transfers of genes from one bacterium carrying the factor to another bacterium lacking the factor by the process of conjugation. It is found in some bacteria only.

Thus, the correct answer is 'F-factor.'

Which is not true of bacterial cell wall?

  1. Not antigenic

  2. Provides shape to bacterium

  3. Not stainable with simple dyes

  4. Made of mucopeptide


Correct Option: A

Murein of bacterial cell wall is derivative of

  1. Vitamin

  2. Fat

  3. Organic acid

  4. Sugar


Correct Option: D
Explanation:

The bacterial cell wall is made up of Peptidoglycan or murein. It is a polymer that is made up of sugars and amino acids. The sugar component is made up of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). NAM is then attached to an amino acid chain of L-alanine, D-glutamic acid, diaminopimelic acid (DAP) and D-alanine. 

Thus, the correct answer is 'Sugar.'

Bacterial cell membrane is made up of

  1. Chitin

  2. Cellulose

  3. Proteins and phospholipids

  4. Fats


Correct Option: C
Explanation:

Bacteria is a unicellular prokaryotic organism. It has a cell wall around the cell membrane. The bacterial cell membrane is made up of proteins and phospholipids. the proteins in are randomly distributed in the phospholipid bilayer of the cell membrane.

Thus, the correct answer is 'Proteins and phospholipids.'

Some bacteria have a capsule outside cell wall. It is made of

  1. Protein

  2. Cellulose

  3. Fat

  4. Mucopolysaccharide


Correct Option: D
Explanation:

Some bacteria have a capsule outside cell wall. It is made up of mucopolysaccharide. The functions of mucopolysaccharide are;

  • It enhances the ability of bacteria to cause disease. 
  • It protects cells from engulfment by macrophages. 
  • It protects cells from desiccation.
Thus, the correct answer is 'Mucopolysaccharide.'

Why is a capsule advantageous to a bacterium?

  1. It provides means of locomotion

  2. It allows bacteria to "hide" from host's immune system

  3. It allows the bacterium to attach to surface

  4. It protects the bacterium from desiccation.


Correct Option: D
Explanation:

  • Bacterial capsule usually consists of a polysaccharide layer that lies outside the cell envelope. The capsule is found in both gram-positive and gram-negative bacterium.
  • The capsule is considered as virulence factor because it enhances the ability of bacteria to cause disease. It protects the bacterial cell from engulfment by macrophages.
  • Capsules also contain water which protects the bacterium from desiccation.
So, the correct answer is 'It protects the bacterium from desiccation'.

Ageing is slow or absent in

  1. Plants

  2. Parrot

  3. Monkeys

  4. Hydra


Correct Option: D
Explanation:

The ageing is very slow or is not seen with the human eye in unicellular organisms but they do age. They undergo constant spontaneous DNA damage that can lead to the death of cells when it no longer able to reproduce. Plants and parrot are multicellular organisms with the higher level of complexity. The complexity is such that cell divisions are limited and when the cell is not able to divide, it ages with the decay of organelles and finally dies. So these organisms do age and die after a perticular period of time. but Hydra is the only species that does not age and lose its capability to reproduce. So we can say that ageing is slow or absent in hydra.

Select the wrong statement of a bacterial cell

  1. Mesosome is formed by extensions of plasma membrane into cell

  2. Pili are elongated tubular structures made up of a protein

  3. Flagellum is composed of filament, hook and basal body

  4. Ribosomes are about 30 nm by 50 nm in size

  5. Fimbriae are small bristle like fibres sprouting out of cell.


Correct Option: D

Which one of the following is absent in eukaryotes?

  1. Nucleolus

  2. Plastid

  3. Mesosome

  4. Ribosomes


Correct Option: C
Explanation:
  • Mesosomes are absent in eukaryotes.
  • Mesosomes refers to the folded invaginations in the plasma membrane of prokaryotes or bacterial cells.
  • Its main function is to increase the surface area of the plasma membrane. 
  • When the surface area of the membrane is increased it helps to carry out the cellular respiration more efficiently.
  • So, the correct answer is 'Mesosome'.

DNA of Escherichia coli is

  1. dsDNA and circular

  2. dsDNA and linear

  3. ssDNA and linear

  4. ssDNA and circular.


Correct Option: A
Explanation:

Escherichia coli is a Gram-negative, facultatively anaerobic bacteria. It is found in the intestine of warm-blooded organisms. It has one circular chromosome. The chromosome contains double-stranded DNA. It may contain some circular plasmids as well as extrachromosomal material.

Thus, the correct answer is option A.

Mitochondria are absent in

  1. Bacteria

  2. Red Algae

  3. Green Algae

  4. Brown Algae.


Correct Option: A
Explanation:
  • Mitochondria are absent in bacteria and blue-green algae.
  • A prokaryotic cell lacks membrane-bound cell organelles and nucleus whereas, a eukaryotic cell consists of membrane-bound cellular organelles and well-defined nucleus.
  • Red algae, green algae and brown algae have eukaryotic cells (well-defined nucleus and cellular organelles).
  • So, the correct answer is 'Bacteria'.

Alga Acetobularia is

  1. Unicellular prokaryote.

  2. Multicellular prokaryote.

  3. Unicellular eukaryote.

  4. Multicellular eukaryote.


Correct Option: C
Explanation:

Acetabularia is a single-celled green photosynthetic algae which contain chloroplasts of the photosynthetic function. Being unicellular it has a complex shape and has been a model organism for the study of gene expression with morphogenesis. It has a large nucleus which contains a genetic material. Because of the presence of nucleus which is absent in prokaryote, these algae is classified in eukaryotes. hence algae Acetabularia is a unicellular eukaryote.

Bacteria with tuft of flagella at one pole are

  1. Amphitrichous

  2. Peritrichous

  3. Atrichous

  4. Lophotrichous


Correct Option: D
Explanation:

A. Amphitrichous bacteria have flagella (single or multiple) extending from both ends of the cell.

B. Peritrichous bacteria have flagella projecting in all directions around the cell.
C. Atrichous bacteria lack flagella. 
D. Lophotrichous bacteria have a tuft of flagella located at the same point on the bacterial cell.
So, the correct answer is 'Lophotrichous'.

Bacteria having a tuft of flagella at both the poles are

  1. Atrichous

  2. Peritrichous

  3. Lophotrichous

  4. Amphitrichous.


Correct Option: D

A bacterial cell contains.

  1. Mesosome, Golgi bodies and nucleoid

  2. Mesosome and Golgi bodies

  3. Mesosome and nucleoid

  4. Golgi bodies and nucleoid


Correct Option: A

Which one of the following statements correctly disguises Nitrosamines and Nitrobacteria?

  1. Nitrosamines is nitrifying bacterium whereas Nitrobacteria is a denitrifying bacterium

  2. Nitrosamine oxidizes ammonia to nitrite while Nitrobacteria oxidizes nitrite to nitrate

  3. Nitrosamine fixes atmospheric nitrogen into ammonia while Nitrobacteria oxidizes ammonia to nitrate

  4. Nitrosamines is responsible for amino acid synthesis while Nitrobacteria is responsible for protein synthesis


Correct Option: A

$NH _3$ in amoeba is excreted through

  1. Food vacuole.

  2. Contractile vacuole.

  3. Plasma membrane.

  4. Both B and C.


Correct Option: D
Explanation:

Amoeba is a unicellular organism. The main waste material in amoeba ammonia (NH$ _3$) along with carbon dioxide (CO$ _2$). The waste material is excreted through body surface (plasmalema) by the process of diffusion. In this process, contractile vacuoles play important role.

Thus, the correct answer is option B.

Entamoeba histolytica is transmitted through

  1. Insect bite

  2. Bird dropping

  3. Improperly cooked pork meat

  4. Food or water contaminated with cysts


Correct Option: D
Explanation:

Entamoeba histolytica is a protozoan protist. It is pathogenic in nature. It resides in the upper part of the human large intestine and causes the disease known as amoebic dysentery or amoebiasis. The symptoms of the disease are abdominal pain, repeated motions with blood and mucus. Entamoeba histolytica is transmitted through food or water contaminated with cysts. A mature cyst is called quadri-nucleate cyst. It has four nuclei and two chromatid bodies. Quadrinucleate cyst is the infective stage.

How many young Amoebae hatch out from a cyst of E. histolytica?

  1. One

  2. Two

  3. Four

  4. Six


Correct Option: A
Explanation:

Entamoeba histolytica is a protozoan protist. It is pathogenic in nature. The type of nutrition present in Entamoeba is parasitic. The parasite is generally with one pseudopodium. The contractile vacuole is absent as there is no need of osmoregulation. It feeds on red blood corpuscles by damaging the wall of the large intestine and reaching the blood capillaries. It produces ulcers. It resides in the upper part of the human large intestine and causes the disease known as amoebic dysentery or amoebiasis. Entamoeba histolytica is transmitted through food or water contaminated with cysts. A mature cyst is called quadri-nucleate cyst. It has four nuclei and two chromatid bodies. Quadrinucleate cyst is the infective stage. Only one young Amoeba with four nuclei hatches out from a cyst of Entamoeba histolytica. However, single cyst of Entamoeba histolytica produces eight Amoebae.

Which one of the following is the basis of biological control of crown gall?

  1. Agro bacterium radiocasted strains contain a plasmid which directs the synthesis of bactenocin

  2. The Ti(tumour inducing) plasmid in Agro bacterium tumefactions is integrated with host plant DNA and is transcribed into mRNA

  3. The cloning strategy leading to a composite(chimeric) plasmid harbouring two or more genes that code for distinct bacteriocins against phytopathogenic bacteria

  4. Agrobacterium radiobacter plasmid interferes with the production of auxin by a tumefaction


Correct Option: A

Match items in Column I with those in Column II -
 

Column I Column II
(A) Peritrichous flagellation (J) Ginkgo
(B) Living fossil  (K) Macrocystes
(C) Rhizophore (L) Escherichia coli
(D) Smallest flowering plant (M) Selaginella
(E) Largest Perennial alga (N) Wolffia

Select  the correct answer with the following

  1. A L ; B J; C M ; D N ; E K

  2. A K ; B J; C L ; D M; E N

  3. A J ; B K; C N ; D L; E K

  4. A N ; B L; C K ; D N; E J


Correct Option: A

Which one of the following is the most important criterion used to classify living organisms into three primary kingdoms, namely-Archaea, Eubacteria and Eukarya?

  1. Genetic relatedness

  2. Morphological characters

  3. Physiological characters

  4. Phenotypic characters


Correct Option: A

Rhodopseudomonas and Rhodospirillum are ______________.

  1. Purple non-sulphur bacteria

  2. Green non-sulphur bacteria

  3. Green sulphur bacteria

  4. Purple sulphur bacteria


Correct Option: A

Yeast die when alcohol concentration reaches about $13$%, still yeast perform alcholic fermentation why?

  1. To obtain ATP

  2. Utilization of $O _{2}$

  3. For oxidation of $NADH _{2}$

  4. Obligate aerobic


Correct Option: A

Cell division is a type of reproduction in 

  1. Unicellular organisms

  2. Multicellular organisms

  3. Both A and B

  4. None of the above


Correct Option: A
Explanation:

Cell division is the process in which a parent cell divides into two or more daughter cells. The unicellular organism divides and results in the formation of daughter cells and hence, cell division is a type of reproduction in unicellular organisms. Thus, the correct answer is option A.

Choose the correct answers from the alternatives given.
Surface appendages used by -bacteria to attach to one another and to host organisms are called:

  1. thylakoids

  2. mesosomes

  3. pili

  4. spirilla


Correct Option: C
Explanation:
A pilus is a thin, rigid fiber made of protein that protrudes from the cell surface. The primary function of pili is to attach a bacterial cell to specific surfaces or to other cells. So, the correct option is 'pili'.

Which of the following organisms do not depend on reproduction to exchange genetic information?

  1. Animals

  2. Plants

  3. Bacteria

  4. Fungi


Correct Option: C
Explanation:

Bacteria have three mechanism for genetic information transfer without undergoing reproduction-
1. Transformation- take up free fragment of DNA floating in medium. 
2. Transduction- transfer of DNA by a virus bacteriophage.
3. Conjugation- direct cell to cell transfer of DNA mediated by plasmid. So, option C is correct, all other options depend on reproduction for exchange of genetic material.

Select the pair that shows the same relationship as the animals in the box.
Amoeba : Paramecium.

  1. Rhizopus : Chlamydomonas

  2. Candida : Saccharomyces

  3. Pteridium : Fasciola

  4. Albugo : Adiantum


Correct Option: A
Correct sequence of layer of bacterial cell envelope from outward to inward is
  1. Cell wall $\rightarrow$ Glycocalyx $\rightarrow$Cell membrane

  2. Cell membrane $\rightarrow$ Glycocalyx $\rightarrow$ Cell wall

  3. Glycocalyx $\rightarrow$ Cell wall $\rightarrow$ Cell membrane

  4. Glycocalyx $\rightarrow$ Cell membrane $\rightarrow$ Cell wall


Correct Option: C
Explanation:

Glycocalyx is the outermost layer of the cell envelope. Cell wall lies between plasma membrane and glycocalyx.

So, the correct answer is 'Glycocalyx → Cell wall → Cell membrane'.

Amoeba and Yeast reproduce asexually by fission and budding respectively, because they are.

  1. Microscopic organisms

  2. Heterotrophic organisms

  3. Unicellular organisms

  4. Uninucleate organisms


Correct Option: A

Which of the following pairs of an animal and a plant represents endangered organisms in India?

  1. Banyan and black buck

  2. Bentinckia nicobarica and red panda

  3. Tamarind and rhesus monkey

  4. Cinchona and leopard


Correct Option: A

Superbugs are

  1. Synthetic bug

  2. Bacteria

  3. Radio nucleotide

  4. Industries


Correct Option: B
Explanation:

Superbugs is a term used to describe strains of bacteria that are resistant to the majority of antibiotics commonly used today. These resistant bacteria can cause pneumonia, urinary tract infections, skin infections and many other diseases that are difficult to treat and may be fatal.

So, the correct answer is 'Bacteria'

Which cell organelle is absent in anaerobic bacteria?

  1. Mitochondria

  2. Golgi body

  3. E.R.

  4. All of the above


Correct Option: D
Explanation:

An anaerobic organism or anaerobic bacteria is any organism that does not require oxygen for growth. It may react negatively or even die if oxygen is present. Mitochondria, Golgi body and ER are organelles of eukaryotic organisms. Since anaerobic bacteria is prokaryotic, they are absent in anaerobic bacteria.

State whether the following statements are true or false.
All denitrifying bacteria are heterotrophs.

  1. True

  2. False


Correct Option: A
Explanation:

Denitrifying bacteria convert nitrates in the soil to free atmospheric nitrogen, nitrogen-fixing bacteria are heterotrophs.

So, the correct option is 'True'.

Commercial lac is produced from .............

  1. The nest of a type of bird

  2. The exudation of a type of insect.

  3. The scale of a type of a fish

  4. The root of a plant


Correct Option: B
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