<span>It was the culmination of research in the 1930s and early 1940s at the Rockefeller Institute for Medical Research to purify and characterize the "transforming principle" responsible for the transformation phenomenon first described in Griffith's experiment of 1928: killed Streptococcus pneumoniae of the virulent strain type III-S, when injected along with living but non-virulent type II-R pneumococci, resulted in a deadly infection of type III-S pneumococci.</span>
Answer:
C) Through genomic imprinting, methylation regulates expression of the paternal copy of the gene in the brain.
Explanation:
The pattern of gene expression wherein either paternal or maternal gene is expressed in specific cells while the other one is prevented from expression is known as genomic imprinting.
In the given example, the maternal copy of the gene on chromosome 15 is expressed in brain cells while its paternal copy is not expressed in these cells. Hence, the pattern of expression of this gene is regulated through genome imprinting. One of the mechanism is methylation of cytidine residues of CpG islands of the DNA that are more frequently present within promoters of the genes.
When the cytidine residues of these sequences are methylated into 5-methylcytidine, the transcription factors do not bind to these promoters preventing the expression of these genes.
Hence, methylation of cytidine residue in CpG islands of the promoters of the gene present on chromosome 15 could have silenced its expression in brain cells.
Answer: For flowering plants, fertilization occurs through a process known as double fertilization. Unlike most plants, double fertilization enables the new seed to grow into a new plant and have a food source to begin growing. Double fertilization occurs within the female part of a plant, the pistol.
explanation: When pollen is formed by the anther, or male part of a plant, it will blow in the wind or attach to an organism that carries it to the top of the pistol, known as the stigma. Once the pollen attaches to the stigma, the pollen germinates and forms a pollen tube that extends into the ovary. Once formed, two sperm cells will be released and fertilize both the egg and the two polar nuclei of the plant to form the zygote and endosperm, respectfully.
Answer:
it would be based on the most common prophase time of year is.
Explanation:
I don't know to be honest.
