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:
All these are emerging infectious diseases.
Explanation:
The emerging infectious diseases refer to the infections, which have appeared freshly within a population or those whose occurrence or geographic range is enhancing briskly or is threatening to upsurge in the coming time. The emerging infections can be a result of:
1. Known agents, which have dispersed to novel geographic locations or new populations.
2. Previously unknown or undetermined infectious agents.
3. Previously known agents whose function in particular diseases was not determined previously.
According to WHO, infectious diseases are emerging at a rate, which has not been noticed before. Since the 1970s, many infectious diseases have been discovered like Ebola, SARS, avian influenza, mad cow disease, and West Nile encephalitis.
With the individuals traveling much more to far greater distances in comparison to the past, encountering with wild animals, and living in more densely populated regions has caused the emerging infectious diseases to spread briskly and is resulting in global epidemics, which is a major worry.
This is true , trees loose their leaves as a part of growth, also in seasons they loose leaves.
The bonds that hold H2O2 together break apart and the atoms are rearranged to form water (H2O) and oxygen (O2) molecules. This happens slowly in store-‐bought hydrogen peroxide, so even in dark bottles, it will 'expire' in a year, or less if it's opened. ... And higher concentrations of H2O2 produce more oxygen.
