Explanation:
A single nucleotide-pair substitution missense mutation causes a change of a single amino acid into another. Aa a result, the produced protein will have an almost normal sequence except for one amino acid.
On the other hand, a frameshift mutation changes the Open Reading Frame (ORF) of the ribosome. The ribosome moves along the mRNA every three nucleotides (codons) and translates them into amino acids that will form the nascent protein. If there is a frameshift mutation (an insertion or deletion of a number of nucleotides not multiple of three) the ribosome will "read" the mRNA differently and will identify different codons than the wild-type sequence, so a large number of amino acids will be different in the mutated protein.
The shuffling of chromosomes that occurs during both fertilization and meiosis can lead to genetic variation. This is because of the independent assortment and crossing over. Hope this answers the question. Have a nice day. Feel free to ask more questions.
Answer:
Desertification is the destruction of the biological potential of the land and it is generally viewed as an advanced stage of land degradation. human activities also cause the process such as poor irrigation practices, deforestation, the expansion and intensive use of agricultural lands, and overgrazing.
Such human activities put enormous pressure on the land by altering its soil chemistry and hydrology. Modern agriculture causing a negative impact on the soil and land by overexploiting the biological and chemical potential of the land.
The statements of the old cell theory are:
1. All organisms are composed of cells
2. The cell is the basic unit of life
3. Cells are produced from existing cells
The modern cell theory's statements are:
1. The cell contains hereditary information which is passed to daughter cells
2. All cells are basically the same in composition and activity
3. All basic functions occur in cells
4. Cell activities depend on intracellular structures
As is visible from the statements, the old cell theory was not as detailed and lacked the understanding of the function, structure and behavior of cells that the current theory possesses. This difference has come about after years of research, through which scientists understood the functions of cells and elaborated on the theory's statements.
Ribosomes, because both prokaryotes and eukaryotes have ribosomes to make proteins.
