Download Answer on Question#48440 – Biology, Microbiology

Answer on Question#48440 – Biology, Microbiology
What would happen if you were to repeat the experiment but, this time, you were to carry out
the lysozyme treatment in a buffered solution containing a high concentration of a lowmolecular weight solute, such as sugar or salt? Would you still get the same results
(clearing/cloudiness) for the Gram-positive/Gram-negative bacterium?
Solution:
Gram-positive
Lysozyme induce lysis of cell wall Gram-positive bacterium. In the hypertonic solution (0.1-0.2
M saccharose) this reaction produce protoplasts (bacterial cell with removed cell wall).
Protoplasts are osmotically fragile and lyse in hypotonic solution. In first case (normal solution)
you can observe full lysis and clear field of vision, in second case (hypertonic solution) –
protoplasts.
Gram-negative
Lysozyme catalyze hydrolysis of peptidoglycan. Peptidoglycan forms around 90% of the dry
weight of Gram-positive bacteria and only 10% of Gram-negative bacteria. Lysozyme treatment
is practically ineffective against Gram-negative bacterium. There is no result of reaction in
isotonic solution and in hypertonic solution you still get the same picture (protoplasts can be
derived from bacteria only after removing cell wall).
Answer:
Gram-positive strains – different results of experiment.
Isotonic solution - clear field of vision;
Hypertonic – cloudy field of vision.
Gram-negative strains – the same result (no difference between isotonic and hypertonic
solution).
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