Answer:
a. The original spraying has caused a permanent mutation, giving the insects genetic resistance to the spray.
Explanation:
This is a practical evidences of mutation and variation, as mechanisms of evolution.
The insecticide is the selective pressure. As a results of continuous spray, the parents of the present mosquitoes must have acquired certain characteristics or traits by gene mutation which makes them resistant to the selective pressure (insecticides), and therefore survive the spray in the past.
Therefore when these resistant parents mated, with high reproductive success (leading to large gene pool of these traits,); variation in the genetic composition increases as the resistant gene is passed from generations to generations in the population. Therefore, the population of present day mosquito with genetic resistance to insecticides increases.They are therefore naturally selected, and able to survive as the present day mosquitoes with high resistance to insecticides.
Cells free Protein expression is described below.
Explanation:
- laboratories came to adopt the technique for protein synthesis for the purposes of answering the age-old question: exactly what role do amino acids play in proteins? Scientists Marshall Nirenberg and Heinrich Matthaei made a huge breakthrough in the answer to this fundamental question in 1961, successfully applying cell-free protein expression to make the connection between nucleotide triplets and the amino acids they encode.
- Using an in vitro translation system based on E. coli, they were able to synthesize the polypeptide polyphenylalanine. From there, they were able to determine the connection between the amino acid phenylalanine and its corresponding codon UUU, essentially discovering the key to cracking the genetic code. This groundbreaking experiment would eventually lead to the deciphering of all the remaining amino acid codons and laid the foundation for the wide variety of translation biology systems that are available today
- Cell-free expression begins with crude extracts generated from cultured cells that are typically engaged in a high rate of protein synthesis, such as immature red blood cells (reticulocytes). These crude extracts are depleted of their endogenous DNA and mRNA, and the cell lysate is subsequently supplemented with macromolecular components required to perform translation, including ribosomes, tRNAs, aminoacyl-tRNA synthetases and initiation, elongation and termination factors.
Answer:
Once common throughout Africa and Asia, elephant numbers fell dramatically in the 19th and 20th centuries, largely due to the ivory trade and habitat loss.
Explanation:
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