Question

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17) Peptidoglycan is a polymer consisting of the following chemical constituents (1 pts) ON-acetyglucosamine (AGA), N-acetylmuramic acid, and a peptide chain ON-AGA, N-AMA, teichoic acid A-AGA, lipopolysaccharides, and peptide chain ON-AMA, lipoproteins, and techoic acid Oprotein, teichooic acid, and diaminopimelic acid 18) Which of the following statements regarding gram-positive cell walls is/are true? i. They are more susceptible to penicillin than are gram-negative cells. ii. They contain a higher percentage of peptidoglycans than do gram-negative cells. iii. Because the mordant attaches the primary dye to the peptidoglycan the gram-positive cells wall do not decolorize easily with organic solvents (e. g., acetone-alcohol) during the gram straining process. iv. The are more resistant to physical disruption than are gram-negative cell walls. Statements i, ii, and ii are true Statements i and ii are ture O Statements il and iv are true O Statement iv is true All of the above are true (1 pts) 19) Which of the following statements is/are true? i. Mesosomes function in cell wall synthesis and the division of nuclear material. ii. The chromatinic area of the cytoplasm is rich in DNA ili. The chromatic area of the cytoplasm is associated with the mesosoma. iv. The bacterial genome possesses one discrete double-stranded circular chromosome. O Statements i, il and ill are correct O Statements i and iliare correct Statements ii and ivare correct O Statement iv is correct All of the above are correct

20.)The term spheroplast applies to a gram-negative bacterial cell which _____.

Select is likely to lyse due to the osmotic shock as your answer	is likely to lyse due to the osmotic shock
Select is just about to ready to produce a spore as your answer	is just about to ready to produce a spore
Select is fighting off an infection by becteriophages as your answer	is fighting off an infection by becteriophages
Select has lost its peptidoglycan layer of the cell wall as your answer	has lost its peptidoglycan layer of the cell wall
Select is lacking a cell wall as your answer	is lacking a cell wal

Answer 1

17) a) N-acetyllucosamine, N-acetlymuramuric acid and a peptide chain

Explanation: Cell wall of bacteria is composed of NAM-NAG chain, this polymer constitute main structure of peptidoglycan layer. These three are core components of peptidoglycan polymer though apart from this some additional components are techoic acid, diaminopimelic acid etc.

18) e) All of the above are true

Explanation: Gram positve bacteria has a thick peptidoglycan layer as comparision to gram negative bacteria which leds to more resistant nature of these bacteria as compare to gram negative. Also thick cell wall, help them stain voilet in crystal voilet staining process as stain dont get remove easily. Gram positive bacteria are susceptible to penicillin due to lack of an outer cell membrane which in case of gram negative give protection to bacteria.

19) e) All of the above are correct

Expalnation : Mesosomes are infloding of plasma membrane which are found in different locations. they may include vesicles tubes etc. It play an important role in cell synthesis and division of nuclear material and it is associated with chromatic region. Apart from this it is also true that bacterial genome is consist of single circular chromosomes in most cases.

20) e) lacks cell wall

Explanation: A spheroplast is a cell which lack its cell wall and found to be surrounded with its cell membrane. they are spherical in shape.

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