The correct answer is <span>C. You cannot view live specimens because the necessary preparation kills cells. </span>
The answer is pretty self-explanatory. Unlike it, regular microscopes can view living creatures such as bacteria or similar.
Answer: Selenium is important for reproduction, thyroid gland function, DNA production, and protecting the body from damage caused by free radicals and from infection
Explanation:
Selenium is important for reproduction, thyroid gland function, DNA production, and protecting the body from damage caused by free radicals and from infection.
Answer:
the spring time is when they call for mates
Answer:
Signal transduction
Explanation:
A signal molecule binds to a receptor.
A conformational change in the signal-receptor complex activates an enzyme.
Second messenger molecules are released.
Protein kinases are activated.
Target proteins are phosphorylated.can be defined as the process in which a physical or chemical signal is transmitted through a cell as a series of molecular events inform of protein phosphorylation are catalyzed by protein kinase and this ultimately result into a cellular response. However, the protein that is responsible for the detection of stimuli is commonly refers to as receptors or sensor.
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.
