Tag: botany

Questions Related to botany

State whether the following statements are true or false.
When treated with crystal violet and subsequently with iodine some bacteria remain colourless and these are called gram +ve bacteria.

botany option b: biotechnology and bioinformatics gram staining microbiology: organisms in industry cell wall and cell membrane

  1. True

  2. False

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Correct Option: A
Explanation:

When treated with crystal violet and subsequently with iodine, some bacteria remain colorless and these are called gram +ve bacteria.

So, the correct option is 'True'.

State whether the following statements are true or false.
Gram stain which is extracted from gram pods is used to differentiate Gram -ve and Gram +ve bacteria.

botany option b: biotechnology and bioinformatics gram staining microbiology: organisms in industry cell wall and cell membrane

  1. True

  2. False

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Correct Option: A
Explanation:

Gram stain is the most important staining procedure. Gram-positive bacteria stain purple, whereas gram-negative bacteria stain pink. 

So, the correct option is 'True'.

Arrange the following steps in a correct sequence as per Gram's staining technique:

Treatment with $0.5$% iodine solution $(1)$, washing with water $(2)$, treatment with absolute alcohol/ acetone $(3)$, staining with weak alkaline solution of crystal violet $(4)$.

botany option b: biotechnology and bioinformatics gram staining microbiology: organisms in industry cell wall and cell membrane

  1. $4\rightarrow 1 \rightarrow 2\rightarrow 3$

  2. $3\rightarrow 2 \rightarrow 1\rightarrow 4$

  3. $3\rightarrow 1 \rightarrow 2\rightarrow 4$

  4. $4\rightarrow 2 \rightarrow 3\rightarrow 1$

Show answer
Correct Option: A
Explanation:

Bacteria can be classified into two groups based upon reaction of bacteria to Gram's stain (Christian Gram, $1884$). Bacteria are first stained with weakly alkaline solution of crystal violet and then treated with $0.5$% iodine solution. This is followed by washing with water and then with alcohol or acetone. Bacteria which retain blue or purple colour are known as Gram $(+)$ bacteria (e.g., Bacillus subtilis). Bacteria which do not retain stain and become colourless are called Gram $(-)$ bacteria (e.g., Escherichia coli). Washing of the stain in Gram $(-ve)$ bacteria is due to high lipid content of their cell wall which gets dissolved in organic solvents like acetone.

So, the correct answer is '$4\rightarrow 1 \rightarrow 2\rightarrow 3$'.

Select the correct option:

Which of the given statements are correct?
(i) Bacillus subtilis is a Gram $(+)$ bacteria.
(ii) Escherichia coli is a Gram $(-)$ bacteria.
(iii) Washing of the Gram's stain in Gram $(-)$ bacteria is due to high lipid content of the cell wall, which gets dissolved in organic solvent like acetone.

botany option b: biotechnology and bioinformatics gram staining microbiology: organisms in industry cell wall and cell membrane

  1. (i) and (ii)

  2. (ii) and (iii)

  3. (i) and (iii)

  4. (i), (ii) and (iii)

Show answer
Correct Option: D
Explanation:

Bacteria can be classified into two groups based upon reaction of bacteria to Gram's stain (Christian Gram, $1884$). Bacteria are first stained with weakly alkaline solution of crystal violet and then treated with $0.5$% iodine solution. This is followed by washing with water and then with alcohol or acetone. 

Bacteria which retain blue or purple colour are known as Gram $(+)$ bacteria (e.g., Bacillus subtilis). 
Bacteria which do not retain stain and become colourless are called Gram $(-)$ bacteria (e.g., Escherichia coli). Washing of the stain in Gram $(-ve)$ bacteria is due to high lipid content of their cell wall which gets dissolved in organic solvents like acetone.
So, the correct answer is '(i), (ii) and (iii)'.

Glycocalyx (mucilage sheath) of a bacterial cell may occur in the form of a loose sheath called _____ or it may be thick and tough called _____.

botany option b: biotechnology and bioinformatics gram staining microbiology: organisms in industry cell wall and cell membrane

  1. Capsule, Slime layer

  2. Slime layer, Capsule

  3. Mesosome, Capsule

  4. Mesosome, Slime layer

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Correct Option: B
Explanation:

Glycocalyx (mucilage sheath) is the outermost layer of the bacterial cell envelope which consists of non-cellulosic polysaccharides with or without proteins. It may occur in the form of loose sheath, called slime layer. If it is a thick covering, it is called capsule. Glycocalyx gives sticky character to the cell and is not absolutely essential for survival of bacteria. It prevents desiccating, protects from phagocytes, toxic chemicals and viruses and serves in attachment. It may give selective advantage through in certain situations.

So, the correct answer is 'Slime layer, capsule'.

Which stain is used the microbe present in the fresh butter milk?

botany option b: biotechnology and bioinformatics gram staining microbiology: organisms in industry cell wall and cell membrane

  1. Methylene blue

  2. Safranin

  3. Iodine

  4. Eosin

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Correct Option: C
Explanation:

a quick version of buttermilk, known as acidified buttermilk, is used to make paneer. The tartness of buttermilk is due to acid in milk, where iodine is suitable.

So, the correct option is 'Iodine'.

'Glycocalyx' is a term used for thin layer of

botany option b: biotechnology and bioinformatics gram staining microbiology: organisms in industry cell wall and cell membrane

  1. Lipoproteins

  2. Phosphoproteins

  3. Glycoproteins

  4. Phospholipids

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Correct Option: C
Explanation:

The glycocalyx is a glycoprotein-polysaccharide covering that surrounds the cell membranes of some bacteria, epithelia and other cells. The glycocalyx is a type of identifier that the body uses to distinguish between its own healthy cells and transplanted tissues, diseased cells, or invading organisms. 
Thus, the correct answer is option C.

The Gram negative bacteria detect and respond to chemical in their surrounding by

botany living world and classification of microbes gram staining microbiology: organisms in industry cell wall and cell membrane

  1. Lipopolysaccharide

  2. Muramic acid

  3. Porins

  4. Volutin granules

  5. Mesosomes

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Correct Option: A
Explanation:

When a decolourizer such as alcohol or acetone is added, it interacts with the lipids of the cell membrane. A Gram-negative cell loses its outer lipopolysaccharide membrane and the inner peptidoglycan layer is left exposed. The crystal violet complexes are washed from the Gram-negative cell along with the outer membrane.

Under the influence of endotoxins of Gram negative bacteria, an endogenous substance is released in the host, which is responsible for increasing the body temperature is 

botany living world and classification of microbes gram staining microbiology: organisms in industry cell wall and cell membrane

  1. Exotoxin

  2. Bacitractin

  3. Pyrogen

  4. Interferon

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Correct Option: C
Explanation:

Pyrogens can be the so called endotoxins or lipopolysaccharides, cell wall components of Gram negative bacteria such as E. coli, Salmonella or Bordetella, but also of the cell walls from Gram positive bacteria, e.g., so called lipoteichoic acids (LTA). When bacteria or viruses invade the body and cause tissue injury, one of the immune systems responses is to produce pyrogens. These chemicals are carried by the blood to the brain, where they disturb the functioning of the hypothalamus, the part of the brain, that regulates body temperature.

Difference between Gram -ve and Gram +ve bacteria is in their

botany living world and classification of microbes gram staining microbiology: organisms in industry cell wall and cell membrane

  1. Cell membrane

  2. Cell wall

  3. Ribosome

  4. Mitochondria

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Correct Option: B
Explanation:

Gram staining differentiates bacteria by the chemical and physical properties of their cell walls by detecting peptidoglycan, which is present in a thick layer in gram-positive bacteria. In a gram stain test, gram-positive bacteria retain the crystal violet dye, while a counterstain (safranin or fuchsine) added after the crystal violet gives all gram-negative bacteria a red or pink colouring.