Answer:
The changes in the single base or nucleotide in the nucleotide sequence and thus changing its complementary base also it is called as point mutations, while when there are insertions or deletions of more than one base pair in the nucleotide sequence it is known as frameshift mutations.
Answer:
C) 30,000
Explanation:
According to the given information, the bacterial mRNA consists of about 800 nucleotides. Three consecutive nucleotides together make one genetic codon which in turn codes for one specific amino acid in the protein encoded by this mRNA.
So, an mRNA with 800 nucleotides will have total 800/3 = 266.67 or 266 genetic codes. The protein encoded by this mRNA would have a total of 266 amino acids.
Given that one amino acid imparts 110 units to the molecular weight of the protein, the protein with 266 amino acids have the molecular weight= 266 x 110 = 29260, that is about 30,000.
Answer:the tails are hydrophobic because of this they face inside away from the water and meet in the inner region of the membrane
Explanation:
Answer:
Until recently, most neuroscientists thought we were born with all the neurons we were ever going to have. As children we might produce some new neurons to help build the pathways - called neural circuits - that act as information highways between different areas of the brain. But scientists believed that once a neural circuit was in place, adding any new neurons would disrupt the flow of information and disable the brain’s communication system.
In 1962, scientist Joseph Altman challenged this belief when he saw evidence of neurogenesis (the birth of neurons) in a region of the adult rat brain called the hippocampus. He later reported that newborn neurons migrated from their birthplace in the hippocampus to other parts of the brain. In 1979, another scientist, Michael Kaplan, confirmed Altman’s findings in the rat brain, and in 1983 he found neural precursor cells in the forebrain of an adult monkey.
These discoveries about neurogenesis in the adult brain were surprising to other researchers who didn’t think they could be true in humans. But in the early 1980s, a scientist trying to understand how birds learn to sing suggested that neuroscientists look again at neurogenesis in the adult brain and begin to see how it might make sense. In a series of experiments, Fernando Nottebohm and his research team showed that the numbers of neurons in the forebrains of male canaries dramatically increased during the mating season. This was the same time in which the birds had to learn new songs to attract females.
Why did these bird brains add neurons at such a critical time in learning? Nottebohm believed it was because fresh neurons helped store new song patterns within the neural circuits of the forebrain, the area of the brain that controls complex behaviors. These new neurons made learning possible. If birds made new neurons to help them remember and learn, Nottebohm thought the brains of mammals might too.
Other scientists believed these findings could not apply to mammals, but Elizabeth Gould later found evidence of newborn neurons in a distinct area of the brain in monkeys, and Fred Gage and Peter Eriksson showed that the adult human brain produced new neurons in a similar area.
For some neuroscientists, neurogenesis in the adult brain is still an unproven theory. But others think the evidence offers intriguing possibilities about the role of adult-generated neurons in learning and memory.
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