Answer:
Option A, Start the reaction by absorbing light energy
Explanation:
Chlorophyll is a green color pigment in plant that helps in entrapping sunlight. Being green in color, it absorbs the blue and red light and reflects the green light. The molecules of chlorophyll gains energy from sunlight and then jumps to higher energy levels by the process known as photo excitation. These excited molecules get ionized to further initiate the process of photosynthesis.
Hence, option A is correct.
Answer:
The correct answer will be option-formation of heterochromatin
Explanation:
Methylation of DNA is the epigenetic mechanism which controls the expression of a gene by adding a methyl group to the cytosine bases in eukaryotic DNA.
The methylation of DNA converts the cytosine residues to the 5-methylcytosine catalysed by DNA methyltransferase enzyme. This results in the silencing of the gene and transcription get switched off.
Studies have shown that DNA methylation is involved in the formation and maintenance of the heterochromatin structure which is the condensed form of the chromatin in which transcription is switched off.
Thus, the formation of heterochromatin is the correct answer.
B. 2.883 million kilometer
Answer:
Kinase-connected receptors or receptor tyro-sine kinases react for the most part to protein and chemical go between. A solitary trans membrane helix interfaces the extracellular restricting area to the intra-cellular space. e.g. insulin, development factors. The official of the ligand triggers the commencement of a few succession of occasions related with phosphorylation of proteins, this is called protein kinase course.
For instance, the official of development hormone to the receptor in the plasma layer causes dimerization (by the actuation of Janus kinase 2, JAK2) of the receptor (conformation change) that bring about auto-phosphorylation of tyro-sine buildups. The official of SH2-space (src homology) protein (Grb-2) to the phosphorylated tyro-sine buildups invigorates cell development through a course of protein phosphorylation.
a). RTKs are the trans-membrane receptors, which have a ligand restricting site on the extracellular area and tyro-sine authoritative on the intra-cellular space. In the event that it comes up short on the extracellular area, the ligand can't tie to the receptor site, so no cell reaction happens.
b). On the off chance that it does not have the intra-cellular space, the ligand can tie to the receptor site, the receptor can't impart signs tot eh intra-cellular area because of the absence of intra-cellular space.
