Lactase refers to an enzyme that can dissociate lactose sugar into glucose and galactose. This enzyme plays an important role in the digestion of milk that comprises high lactose sugar. In case, if a mutation occurs in the gene codon of lactase, then two possibilities can take place. These are as follows:
1. Loss of mutation: In this case, the person becomes lactose intolerant because of mutation in lactase gene codon. Due to this, there is low mRNA expression and thus low production of the enzyme lactase. This is also known as lactase non-persistent phenotype.
2. Gain in mutation: In this case, the person gain an increase in mRNA expression of the lactase gene, thus more production of lactase takes place than usual. This kind of individual exhibits lactase persistent phenotype.
The stem and the middle of the peatals
Answer:
A mutation in Ras protein which will cause hyperactivity will eventually lead to cancer.
Explanation:
Ras protein was first discovered in Rous sarcoma virus (RSV) and it is a proto-oncogene product. In normal conditions, it plays an important role in cellular signalling but in case of gain of function/hyperactivity it gets converted into cellular oncogene. In several types of cancers a point mutation has been reported in Ras protein.
Just like G protein, it is also a GTPase switch protein but unlike G protein which is trimeric, it is monomeric. In the plasma membrane, it is attached with the help of lipids like prenyl or palmitoyl groups. During signal transduction pathway when it gets activated, it downstream activates MAPK pathway and causes gene expression but when it gets hyperactivated it causes over expression of genes leading to cancer.
The answer tot his question is:
<span>Fill in the blank.
</span>A scientific ___________ is a proposed explanation that can be tested."<span>Scientific Theory."
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