23Bacteria

📚
PLASMIDS
▢ F Plasmid / Fertility Plasmid: Sex determination
▢ Key Point: Extrachromosomal circular DNA → independent replication
📚
SEX PILI
▢ Function: Conjugation
▢ Sexual Dimorphism: Male bacterium
📚
HISTORY

Table 1: Bacteria: Historical Points

Point
Scientist
Term 'bacterium'
Ehrenberg
Discovery of bacteria
Leeuwenhoek
Germ theory of disease
Louis Pasteur
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CHARACTERISTIC FEATURES
▢ Genetic Material:
  • •
    DNA + RNA both present
  • •
    Primitive DNA → nucleoid / genophore / incipient nucleus
▢ Cell Wall Sugars:
  • •
    N-acetyl glucosamine / NAG
  • •
    N-acetyl muramic acid / NAM
  • •
    Unique bacterial cell wall sugars
▢ Ribosome: 70S ribosome = 50S + 30S
▢ Mesosome:
  • •
    Respiration
  • •
    Reproduction during cell division
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GRAM POSITIVE VS GRAM NEGATIVE BACTERIA

Table 1: Gram +ve vs Gram -ve

Feature
Gram +ve Bacteria
Gram -ve Bacteria
Peptide linkage
Horizontal + vertical peptide linkage
Either horizontal OR vertical peptide linkage
Mesh
Dense mesh
Loose mesh
Stain retention
Stain does not come out
Stain comes out
Outer fibrous layer
Teichoic acid
Absent / not teichoic acid
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DISTRIBUTION
▢ Nature: Ubiquitous
📚
SIZE

Table 1: Bacterial Size

Type
Bacterium
Smallest known bacterium
Dialister pneumosintes
Largest known bacterium
Epulopiscium fishelsoni
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SHAPE

Table 1: Bacterial Shapes

Shape
Meaning / Arrangement
Coccus
Rounded
Micrococcus
Single coccus
Diplococcus
Group of 2 cocci
Streptococcus
Chain arrangement
Staphylococcus
Bunch of grapes-like arrangement
Sarcinae
Cubes of 8, 64 or more bacteria
Bacillus
Rod-shaped
Vibrio
Comma-shaped
Spirillum
Spiral-shaped
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ARRANGEMENT OF FLAGELLUM

Table 1: Flagellar Arrangement

Type
Arrangement
Atrichous
No flagella
Monotrichous
One flagellum at one end
Cephalotrichous
Group of flagella at one side
Amphitrichous
One flagellum at both ends
Lophotrichous
Group of flagella at both sides
Peritrichous
Flagella all over surface
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CELLULAR STRUCTURE
▢ Outer Coverings:
  • •
    Capsule / slime layer
  • •
    Cell wall
  • •
    Plasma membrane / cell membrane
▢ Plasma Membrane Specialization: Mesosome
▢ Appendages:
  • •
    Flagellum
  • •
    Fimbriae / pili
▢ Matrix:
❖ Nucleoid / Genophore: Primitive nuclear region
❖ Episomes:
◉ Definition: Extranuclear genetic material → free state OR integrated state
◉ Plasmid: Circular DNA molecule → independent replication from bacterial chromosome
◉ Importance: Non-essential but may provide selective advantage
◉ Episome Meaning: Plasmid attached to cell membrane OR integrated into bacterial chromosome
◉ Examples:
  • •
    F-factor
  • •
    Temperate phage
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REPRODUCTION
▢ Vegetative Reproduction:
  • •
    Budding
  • •
    Binary fission
▢ Asexual Reproduction:
  • •
    Endospore formation
  • •
    Conidia formation
▢ Sexual Reproduction:

Table 1: Genetic Recombination in Bacteria

Type
Studied By
Studied In
Conjugation
Lederberg + Tatum
E. coli
Transformation
Griffith
Diplococcus pneumoniae
Transduction
Lederberg + Zinder
Salmonella typhimurium
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PLANT DISEASES CAUSED BY BACTERIA

Table 1: Bacterial Diseases in Plants

Disease
Bacterium
Soft rot of potato
Pseudomonas solanacearum
Potato wilt
Pseudomonas solanacearum
Citrus canker
Xanthomonas citri
Bacterial blight of paddy
Xanthomonas oryzae
Black rot of cabbage
Xanthomonas campestris
Tundu disease in wheat
Corynebacterium tritici
Fire blight of apple and peach
Erwinia amylovora
Crown gall of sugar beet
Agrobacterium tumefaciens
Q1.
Nitrosomonas is: [IOM - 1997]
📅IOM - 1997
Q2.
The bacteria found in the root nodules of Leguminaceae is: [IOM -1999]
📅IOM -1999
Q3.
Denitrifying bacteria convert: [IOM - 1999]
📅IOM - 1999
Q4.
Which of the following is rod shaped bacteria? [MOE - 2064]
📅MOE - 2064
Q5.
Bacteria in an ecosystem act as: [MOE-2060]
📅MOE-2060
Q6.
Circular DNA is found in: [MOE - 2063]
📅MOE - 2063
Q7.
On unusual condition one of the following bacteria produces spore [IE - 2002]
📅IE - 2002
Q8.
In plants, fungi and bacteria, the proton pump in cells creates a negative membrane potential transporting which ion from the cytoplasm to the extracellular fluid? [IE - 2002]
📅IE - 2002
Q9.
Most primitive organisms are [IE -2003]
📅IE -2003
Q10.
In general bacteria, genes are regulated at: [IE - 2006]
📅IE - 2006
Q11.
Nitrogen fixation by organism requires conditions that are: [IE - 2007]
📅IE - 2007
Q12.
Cyanobacteria are [IE - 2008]
📅IE - 2008
Q13.
Which of the following kingdoms consist organism that can fix nitrogen? [IE - 2009]
📅IE - 2009
Q14.
Archaebacteria contains [IE - 2005]
📅IE - 2005
Q15.
What is wrong about fertility factor F+ present in bacteria? [BPKIHS 2002]
📅BPKIHS 2002
Q16.
Which is incorrect about bacteria? [BPKIHS 2002]
📅BPKIHS 2002
Q17.
"Little leaf of brinjal" is caused by: [BPKIHS 2004]
📅BPKIHS 2004
Q18.
Which of the following bacteria reduces the nitrates into gaseous form of Nitrogen? [BPKIHS 2006]
📅BPKIHS 2006
Q19.
E. coli in human intestine is present as [BPKIHS 2004]
📅BPKIHS 2004
Q20.
Bacterial DNA is identified as: [BPKIHS 2006]
📅BPKIHS 2006
Q21.
Which of the following is nitrifying bacteria [BPKIHS 2006]
📅BPKIHS 2006
Q22.
A bacterial cell divides every 20 minutes. After time period of 3 hrs, how many bacterial cell will be there? [BPKINS - 2016]
📅BPKINS - 2016
Q23.
Plasmids are [BPKIHS - 2014]
📅BPKIHS - 2014
Q24.
Bacteria without flagella is  [BPKIHS - 2013]
📅BPKIHS - 2013
Q25.
Bacteria are  [BPKIHS - 2011]
📅BPKIHS - 2011
Q26.
Bacterial DNA is  [BPKIHS - 2012]
📅BPKIHS - 2012
Q27.
Bacteria without flagella is   [IOM-2016]
📅IOM-2016
Q28.
Atmospheric nitrogen is converted to nitrogenous compound is [IOM-2016]
📅IOM-2016
Q29.
Which of the following bacteria shows darting type mortality? [IOM-2014]
📅IOM-2014
Q30.
Nitrosomonas is  [IOM-209]
📅IOM-209
Q31.
Which one of the following is a free living aerobic nitrogen fixing bacteria?  [IOM-2013]
📅IOM-2013
Q32.
The viral infection cycle that will cause the viral DNA to become integrated into the bacterial DNA is called  [IOM-2015)
📅IOM-2015)
Q33.
Spherical bacterium is referred as  [MOE 2014
📅MOE 2014
Q34.
Which one of the following is absent in bacteria?  [MOE 2012)
📅MOE 2012)
Q35.
Rod shaped bacteria are called  [MOE 2068)
📅MOE 2068)
Q36.
Akinetes occur in  [MOE 2010)
📅MOE 2010)