<em><u>Answer</u></em>
<em><u>about 3.9 billion years ago</u></em>
<em><u>about 3.9 billion years agoThe most recent common ancestor of all currently living organisms is the last universal ancestor, which lived about 3.9 billion years ago.</u></em>
The answer is Bioenergetics. Hope this helps.
The properties of the original elements are completely changed.
For example, in the compound called "iron(II) sulphide", it is composed of iron and sulphur, that are chemically combined together. The element iron is attracted to magnets. Meanwhile, iron(II) sulphide is not attracted to magnets.
Another example is where sulphur has a yellow colour, but iron(II) sulphide has a brownish colour. As we can see, even the physical properties (colours) are completely different.
Therefore, the properties of the original elements are completely changed when they're combined into compounds.
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 phospholipid bilayer is a universal component of all cell membranes. Each phospholipid molecule has a hydrophobic(water repelling) and a hydrophilic( attracted to water) end. This allows the phospholipids to arrange themselves in a way that makes a cell membrane not able to dissolve in water. The bilayer is also semi-permeable which allows only certain molecules to enter the cell.
hope this helps
