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sergey [27]
2 years ago
5

Once DNA was shown to be the primary genetic material of life, a race among scientists took place to work out its structure. Whi

ch concept came from studying the amounts of each DNA base in different organisms?
Biology
1 answer:
Naily [24]2 years ago
8 0

Answer:

The discovery of deoxyribonucleic acid (DNA) forever changed the understanding of genetics, the study of how physical and physiological inheritance is passed down from generation to generation.

The DNA molecule was first identified in the second half of the 19th century. A century later, in the middle of the 20th century, the golden age of discoveries in genetics began, when the structure and functioning of the genetic code was defined.

Today, scientists are focused on researching how to edit DNA to correct mistakes and cure diseases of genetic origin.

DNA was first isolated in 1869 by the Swiss biologist Johan Friedrich Miescher. While studying the chemical composition of white blood cells, he observed that within the cells there was an isolated substance rich in phosphates, without sulfur and resistant to proteases, something that did not correspond to the typical structure of lipids or proteins.

Miescher baptized that new molecule as nuclein, since it was found in the nucleus of all the cells studied.

Between 1885 and 1901, the chemical composition of DNA began to be defined. In 1889 Richard Altmann, a German pathologist who had been a disciple of Miescher, redefined this substance with the term "nucleic acid".

For his part, the German doctor Albert Kossel discovered the existence of carbohydrates and some compounds or nitrogenous bases which he called "adenine", "guanine", "cytosine" and "thymine" within the DNA molecule. This discovery earned him the Nobel Prize for Medicine in 1910. The 20th century began with great advances in DNA research. During the 1920s, Russian-American biochemist Phoebus Levene determined the existence of RNA, another nucleic acid necessary for the transmission of genetic information.

Levene also detected the presence of phosphate group and a type of sugar called ribose, two essential components in the formation of DNA. Later, the biochemist discovered that the phosphate group, sugar, and nitrogenous bases bound together to form nucleotides.

Once the shape and composition of DNA has been discovered, the latest studies focus on how it works: seeing what chemical reactions take place inside the cell in order to try to reproduce them in the laboratory.

Explanation:

In this way, genetic editing techniques aim to modify the genetic code of some cells whose DNA is incorrect or damaged, which can cause disorders and diseases.

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Mashcka [7]

Answer:

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4 0
1 year ago
Let's consider a scenario in which the resting membrane potential changes from −70 mv to +70 mv, but the concentrations of all i
Nookie1986 [14]
<span>Let's consider a scenario in which the resting membrane potential changes from −70 mV to +70 mV, but the concentrations of all ions in the intracellular and extracellular fluids are unchanged. Predict how this change in membrane potential affects the movement of Na+. The electrical gradient for Na+ would tend to move Na+ Outside the cell (extracellular) while the chemical gradient for Na+ would tend to move Na+ Inside the cell (intracellular).

The electrical gradient is defined as the + goes to the - and the - goes to the +
Na + has a positive charge, but there's more positive charge inside the cell than outside (due to potassium), therefore, Na+ goes extracellular (out)
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5 0
2 years ago
Why are lamarck's ideas called scientific hypotheses and not scientific theories?
dsp73
<span><span>This is because his hypothesis that an organism can pass on characteristics that it has acquired during its lifetime to its offspring are not approved or </span>verified. His hypothesis of the notion of inheritance of acquired traits was supplanted by Mendelian genetics. Yet, because of the discovery of epigenetics and somatic hypermutation interest in Lamarckism has continued.</span>
3 0
2 years ago
Read each of the sentences that describe a phase of meiosis. Place each sentence into the correct box.
Ksivusya [100]
Can you show the picture of the question please?
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2 years ago
Autonomic centers in the ________ exert neural control over hormone secretion by the adrenal medullae. a) pineal gland b) pituit
frez [133]

Answer:

The correct answer will be option-E

Explanation:

The autonomic nervous system or ANS activity in the brain is mainly controlled and regulated by the hypothalamus structure. The autonomic centres of the hypothalamus control the hormonal secretion adrenal medulla like adrenaline and norepinephrine.

The secretion of the hypothalamus controls the activity of the vasomotor center which help maintain the blood pressure.

Thus, option-hypothalamus is the correct answer.

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2 years ago
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