Polysaccharides like Cellulose form insoluble micro-fibrils making it resistant to degradation and enzymatic activity.
<u>EXPLANATION: </u>
- Polysaccharides components in general broken down monosaccharides and they are very little enough to be absorbed by the body.
- But the polysaccharide like cellulose cannot be absorbed by our body.
- Cellulose is made up of simple polymers that form insoluble micro-fibrils results in resistant to degradation and enzymatic activity.
- Also, molecules of each micro-fibril are so tightly packed structure and prevent the penetration of enzymes.
- Thus, cellulose degradation requires a complex enzyme and cellulose.
Answer:
D.) repressor DNA-binding site mutation
Explanation:
lacl prevents the repressor polypeptide is a mutant that prevent operon from binding lactose, and thus will bind to the operator and be non-inducible.. This mutant will represses the lac operon whether lactose is present or not and the lac operon will not be expressed. It is also called“super-supperesor".
The lacI locus – One type of mutant allele of lacI (callled I-) prevents the production of a repressor polypeptide or produces a polypeptide that will not allow to bind to the operator sequence.
This is also a constitutive expresser of the lac operon because absence of repressor binding permits transcription.
A. Tetanus does not refer to the shape of a bacterium.
<h2>b) option is correct </h2>
Explanation:
- Some bacterial toxins cause disease by altering the activity of G protein, cholera toxin is one of them
- Cholera toxin catalyse ADP ribosylation of Gs and blocks GTPase activity thus Gs GTP become permanently active
- Constitutive activation of Gs protein continuously induce adenylyl cyclase, cytosolic cAMP level rises that leads to activation of protein kinase A (pKA)
- Activated pKA catalyse phosphorylation of two transmembrane proteins of intestinal epithelial cells:
- CFTR cause excessive outflow of Cl- ion and Na+ H+ exchange cause efflux of Na+ ion, both enters in gut and form Na+ Cl-
- Na+Cl- leads to outflow of water from the gut, resulting in diarrhea and dehydration and this condition may cause death of organisms due to loss of water and ions
