Monera - Classification , General characters , Examples, Multiple Choice questions: NEET


Overview : The Monera got status of  phylum by Ernst Haeckel. The kingdom Monera includes prokaryotes. Bacteria are the sole members of the Kingdom Monera. Organisms of kingdom monera are regarded as  lower-level organisms They have single cell or cellular body organisation in their body regulates all the functions of the body.

General Character of Kingdom Monera

👉They are microscopic and prokaryotic with primitive nuclei.

👉The nucleus is without a nuclear envelope, nucleolus, nucleoplasm, histone protein and true chromosomes

👉Only DNA is present in the form of Nucleoid.

👉The cell wall is non cellulosic composed of polysaccharides and amino acids

👉The members  may be unicellular as in eubacteria and filamentous as in cyanobacteria.

👉These organisms may be motile  or non-motile.

👉They are autotrophic, heterotrophic, parasitic or saprophytic but the majority of bacteria are heterotrophic.

👉The monerans are photoautotrophs like cyanobacteria or chemoautotrophs like  Thiobacillus.

👉The reproduce mainly by fission but in some conditions they form spore for the reproduction.

👉In unfavourable condition , they transfer their DNA from one bacteria to another. Sexual reproduction, mitosis, and meiosis are absent.


TYPES OF BACTERIA ON THE BASIS OF SHAPE 

🌑Bacteria are grouped into four categories based on their shape.
🔴The bacteria in  spherical shape are called Coccus. For Ex - Streptococcus.
🔴 The rod-shaped bacteria are  Bacillus. For Ex - Lactobacillus.
🔴Vibrium are comma-shaped bacteria. For Ex- vibrio cholerae

🔴 The spiral shaped bacteria are termed  Spirillum  For Ex- Rhodospirillum.

Classification of Monera-🌑Kingdom Monera is divided into two sub-kingdoms- Archaebacteria and Eubacteria. 

Archaebacteria 
🔴Bacteria are found  everywhere even in such harsh climates where life is very difficult to survive but They survive  in  hot springs, deserts, snow and deep oceans etc.
🔴These groups of bacteria are primitive and supposed to have appeared around   4 to 5 billion years back.
🔴Archaebacteria survive in harsh climates because of their special cell wall Which is made up of polysaccharides and protein.

🔵Extra Shot of Archaebacteria
Due to the presence of special cell walls they differ from other bacteria.They have special pigment bacteriorhodopsin to perform photosynthesis hence they are autotrophs.
🔴Archaebacteria are broadly  classified  into three types:

🌑Methanogens
🔴They are responsible to release the methane while performing  their metabolic activities.
🔴Methanogens are also present in the gut of several ruminant animals such as cows and buffaloes.  They also produced biogas from the dung of  animals in which methane is one of the important constituents.
🔴Methanogens can not survive in the presence of oxygen. Hence they can be found in swamp and marshes in areas in which all oxygen is consumed. The smell in these areas  is due to the production of methane. For Example Methanol bacillus, Thiobacillus
🔴Thermoacidophiles are found in  extremely hot and acidic climates  and can also  be found in hot springs.
🔴Most of the thermoacidophiles use hydrogen sulphide as their energy source. They precipitate bicarbonate into carbonate due to their activities. For Example  Thermoplasma, Picrophilus, Thermo cocci, Pyrococcus, Sulfolobus
🔴Halophiles are those that are found in salty environments like a great salt lake or dead sea. These environments are extremely basic. For Example - Halobacteria, Halococcus,

Subkingdom Eubacteria:

🔴There are true bacteria. They are featured by the presence of a rigid cell wall made up of Peptidoglycan. Their cell membrane contains lipids.

🔴If bacteria are motile like E. coli a flagella  is present. The flagella are made up of protein flagellin.


Cyanobacteria  

🔴They also known as blue green algae. They  have chlorophyll similar to green plants hence called  photosynthetic autotrophs.

🔴The cyanobacteria are unicellular, colonial or filamentous, freshwater or marine or terrestrial algae.

🔴The colonies are generally surrounded by a gelatinous sheath. They often form blooms in polluted water bodies.

🔴Some of these organisms can fix atmospheric nitrogen in specialized cells called heterocysts. Example:  Anabaena, Nostoc, Oscillatoria, and Spirulina, etc.

🌑Mycoplasma are smallest cell without cell wall and survive without oxygen. Mycoplasma are pathogen of both plant and animals.

Chemoautotrophs

🔴They are chemosynthetic autotrophic bacteria. 🔴They oxidize  inorganic substances like  hydrogen sulphide, nitrates, nitrites, methane, and ammonia. During the oxidation of inorganic substances, they release energy in the form of ATP.

🔴They are also involved in nutrient cycling or biogeochemical cycles like nitrogen, phosphorus, iron and sulphur. For Example Nitrobacter, Nitrosomonas 

🔵Extra Shot of Eubacrteria

🔴Some bacteria also contain short appendages like structures that are modification of  the cell surface called pili.

🔴These pilli play a role  in sexual reproduction and help to attach with the body of the host.Eubacteria can be grouped into Gram-positive bacteria and Gram-negative bacteria on the basis of staining property.

🔴Eubacteria are divided into following categories.

Actinomyces

🔴They are gram-positive bacteria and found in soil. Sometimes they are considered as   fungi.

🔴They produce commonly used antibiotics like streptomycin and tetracycline. For Example - Streptomycin,Mycobacterium etc.


Enterobacteria 

🔴They are gram-negative, rod-shaped bacteria and they are aerobic heterotrophs.

🔴They are pathogenic and cause diseases like bubonic plague and cholera. For Example -  Salmonella, Vibrio Cholerae, 


Pseudomonas

🔴They are gram-negative bacteria and are  rod shaped.

🔴They are  heterotrophic bacteria and commonly found in soil. Some of them are pathogens to plants. For Example  Pseudomonas

🔴Rickettsias and Chlamydias are small gram-negative bacteria. They are pathogens of human For example -  Rickettsia, Chlamydia

🔴Spirochaetes are long and have a coil-shaped cell.They have flagella at both ends.

🔴They are commonly aquatic and pathogens. For Ex- Treponema.



1.Which of the following statement is not correct.
A. Members of monera are exclusively bacteria.
B. Their body organisation  are cellular.
C. Moneran have a well developed nuclear membrane. 
D. They have non cellulosic cell wall.
Answer : C  

2. Cell wall of Moneran are non cellulosic, composed of :
A. Polysaccharide & Amino acid
B. Amino acid & lipid 
C. Polysaccharides only
D. Amino acids only.
Answer ; A 

3.Consider the following mode of nutrition in Moneran and select the correct code:
1.Chemosynthetic Autotroph
2. Photosynthesis Autotroph
3. Saprotroph Heterotroph
4. Parasitic Heterotroph
A. 1, 2 and 3
B. 2, 3 and 4
C. 1, 3  and 4
D. 1, 2  3  and 4
Answer : D 


4. Bacteria are divided into Coccus, Vibrio, Spirullum and Bacillus on the basis of :
A. Nutrition  B. Shape
C. Cell wall    D. Flagella
Answer : B 

5. Which of the following pair in not correctly matched.
A. Coccus : Sherical
B. Bacillus : Rod shape
C. Vibrio : J shape
D. Spirullum : spiral 
Answer : C  

6. Consider the following statement and select the correct code:
1. Chemosynthetic autotrophs bacteria synthesised their food from inorganic substrate.
2. The majority of bacteria are heterotroph, derive nutrition from living organism or dead matter.
A. Only 1    B. Only 2
C. Both 1 and 2 
D. Neither 1 nor 2
Answer : C  

7. Archaebacteria are present in harsh climate and can survive in extreme condition due to having 
A.  Size & shape 
B.  Cell wall 
C.  Complex behaviour 
D. Simple body structure 
Answer : B  

8. Which of the following pair is not correct with respect to  Archaebacteria and their habitat condition .
AHalophiles : Extreme temprature 
B. Methanogen  : Ruminant Gut of cow & Buffalo 
C. Methanogen : Marshy area
D. Halophiles : Salty Environment 
Answer: A  

10. Which group of Archaebacteria  are found in  extremely hot and acidic climates  and can also  be found in hot springs.
A. Halophiles
B. Thermoacidophiles
C. Methanogen
D. Halophiles & Methanogen.
Answer: B

11. Which group of Archaebacteria produces biogas or gobar gas from the cow dung.
A. Halophiles
B. Thermoacidophiles
C. Methanogen
D. Halophiles & Methanogen.
Answer: C

12. Which of the following statement is Correct.
A. Archaebacteria are true bacteria.
B. Eubacteria are false bacteria.
C. All of the Eubacteria have flagella therefore they are motile.
D. Eubacteria are characteristic of rigid cell wall.
Answer: D

13. Which of the following statement is not Correct with respect to blue green algae or cyanobacteria.
A. They  have chlorophyll a similar to green plants.
B. The cyanobacteria are unicellular, colonial or filamentous, freshwater or marine or terrestrial algae.
C. The colonies are generally surrounded by a gelatinous sheath.
D. All of the cyanobacteria
have flagella therefore they are motile.
Answer : D

14. Consider the following statement and select the correct code
1. Cyanobacteria often form bloom in polluted water.
2. Chemosynthetic bacteria help in recycling of nutrient like nitrogen phosphorus iron etc.
A. Only 1 B. Only 2
C. Both 1 and 2
D. Neither 1 nor 2
Answer : C

15. Which of the following statement is not correct.
A. Chemosynthetic bacteria use nitrite ammonia for the production of ATP.
B. Cyanobacteria fix atmospheric nitrogen by having special cell called heterocyst.
C. Methanogen produce biogas from the cattle dung.
D. Nostoc and Anabaena are chemosynthetic Autotrophs
Answer : D

16. Heterotrophic bacteria is not involved in
A. Formation of curd
B. Formation of Antibiotics
C. Fixation of Nitrogen in legume
D. Formation of ATP by using nitrite, nitrate and ammonia.
Answer: D

17. Which group of bacteria damage the crop and causes various disease to humans being.
A. Chemosynthetic bacteria
B. Photosynthetic bacteria
C. Heterotrophic bacteria
D. Autotrophic bacteria
Answer : C

18. Bacteria reproduce mainly by the
A. Fission
B. Spore
C. Sporulation
D. Budding
Answer : A

19. Consider the following mode of reproduction of bacteria , take place during unfavourable condition and select the correct code:
1. Fission 2. Budding
3. Spore formation
4. Exchanges of genetic matter
A. 1 and 4 B. 2 and 4
C. 3 and 4 D. 1 and 2
Answer : C

20. Which of the following statement is not correct for the Mycoplasma.
A. They are pathogen and disease causing agent of plants and animals
B.They do not have cell wall .
C. They can not survive without oxygen.
D. Mycoplasma are one of the smallest cell.
Answer: C

 














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