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.
Answer:
I think this would help you Sun, water, food, animals, etc.
This membrane mimics the plasma membrane that is around animal cells. In order to explore how water moves in and out of a cell, one cell was weighed and then submerged in hypertonic solution. The other egg was weighted and submerged in hypotonic solution. It was predicted that the egg submerged in hypertonic solution would decrease in mass. It was predicted that the egg submerged in hypotonic solution would increase in mass.
Explanation:
The outermost covering of an animal cell is the plasma membrane. It is a selectively permeable membrane that allows only selective molecules to pass through it.
A solution having higher concentration of solute than the cell cytoplasm is called a hypertonic solution.
A solution having lower concentration of solute than the cell cytoplasm is called the hypotonic solution.
The movement of water molecules from the region of its higher concentration to the region of its lower concentration through a semipermeable membrane is called osmosis.
A cell placed in hypertonic solution will undergo exosmosis so it will lose water and its mass will decrease.
A cell placed in hypotonic solution will undergo endosmosis of water so it will gain water and its mass will increase.
