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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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A hypothesis is a general principle or explanation that is derived from observations. Suppose you make the following observation
mr_godi [17]

Question continued

For each statement below, mark "True" if it would be a valid hypothesis, based on these three observations alone, and mark "False" if it would not be a valid hypothesis.

1. The onion cells I looked at have a nucleus.

2. All onion cells have a nucleus.

3. All cells have a nucleus.

4. Some cells have a nucleus.

5. Only onion cells have a nucleus.

6. If I look at 10 skin cells from my hand, each one will have a nucleus.

Answer:

1. The onion cells I looked at have a nucleus. false - this is not a hypothesis, it is an observation of the evidence you collected.

2. All onion cells have a nucleus. true - this is a valid hypothesis based on the evidence you have gathered from looking at onions

3. All cells have a nucleus. true  - this is a hypothesis based on you looking at 3 cell types, several samples of each, and finding that they all have a nucleus

4. Some cells have a nucleus. false - this is not a valid hypothesis. Your evidence so far suggests all cells have a nucleus

5. Only onion cells have a nucleus. - false, you know this to be false as other cell types you analysed had a nucleus

6. If I look at 10 skin cells from my hand, each one will have a nucleus. false - a hypothesis is supposed to be a general principle that is backed up by evidence, this is too specific.

4 0
2 years ago
Check your understanding
wel

The fraction of offspring with black coat color and straight fur is 9/16.

Explanation:

Information given:

black coat colour and straight fur - dominant genotype BBCC, BbCc

yellow coat colour and curly fur - recessive genotype  bbcc

Both the traits are independently assorted. The fur colour and fur type is not present on the same chromosome and are not sex linked.

The genotype of the parents are:

BbCc X BbCc

Punnet square shows:

          BC           Bc          bC        bc

BC  BBCC   BBCc        BbCC   BbCc

Bc  BBCc   BBcc          BbCc    Bbcc

bC BbCC    BbCc         bbCC   bbCc

bc  BbCc      Bbcc         bbCc    bbcc

9 BLACK STRAIGHT

 3 BLACK CURLY

 3 YELLOW STRAIGHT

  1  YELLOW CURLY

9/16 is the fraction of progeny to be black coat colour and straight fur.

5 0
2 years ago
There are three major types of cells in the lymphoid tissues of the body. One category, the ____________, contains immunocompete
KonstantinChe [14]

Answer:

See the picture attached

Explanation:

5 0
2 years ago
Tasha is testing the effect of blue-colored light on the growth of tomato plants. Which is the independent variable in this expe
tester [92]

Answer:

the answer to this question is the light colour

6 0
2 years ago
During the citric acid cycle, the production of co2 is the result of the _____ of intermediate compounds of the citric acid cycl
katen-ka-za [31]

During the citric acid cycle, the production of co2 is the result of the oxidation of intermediate compounds of the citric acid cycle coupled to the production of ATP/GTP.

<span>The citric acid cycle has an essential role in metabolism, and it consist of series of steps. The citric acid cycle is also known as Krebs cycle. One other name of this cycle is Tricarboxylic Acid (TCA)cycle.</span>

7 0
2 years ago
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