Answer:
Can be used for simple experiments at home or in the classroom
Answer:
D
Explanation:
Enzymes can only fit into the base it was made for.
Answer:
not significant to the overall mass of the atom
Explanation:
The mass number of an atom is the combination of the mass of the protons and neutrons. Electrons are not included because their mass are so insignificant that is doesn't change the total mass much, therefore they are left out. The mass of an electron is about 1,830 times smaller than protons and neutrons.
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.
