Question

1.Дан фрагмент одной цепи молекулы ДНК A-Г-Т-А-Ц-Ц-Г-А-Т-А-Ц-Г-А-Т-Т-Т-А-Ц-Г . Построить вторую цепь ДНК , найти массу и длину ДНК , количество водородных связей в этом отрезке ДНК и построить информационную ДНК 2.В молекуле ДНК обнаружено 880 гуаниновых нуклеотидов , которые составляют 22% от общего количества нуклеотидов этой ДНК . Найти сколько содержится других нуклеотидов (А,Т,Ц) в этой ДНК . Найти длину ДНК

Answer 1

1) Вторая цепь ДНК: Т-Ц-А-Т-Г-Г-Ц-Т-А-Т-Г-Ц-Т-А-А-А-Т-Г-Ц
     ДНК строится по принципу комплементарности.Комплементарнсть-это соответствие молекул:   
        Аденин -(соответствует)--Тимину 
         Гуанин ---Цитозину

Answer 2

Building the Second DNA Strand

To build the second DNA strand based on the given fragment, we need to identify the complementary base pairs. In DNA, adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G).

The given fragment is: A-G-T-A-C-C-G-A-T-A-C-G-A-T-T-T-A-C-G

To find the complementary bases, we replace each base with its complementary pair:

A-G-T-A-C-C-G-A-T-A-C-G-A-T-T-T-A-C-G T-C-A-T-G-G-C-T-A-T-G-C-T-A-A-A-T-G-C

The second DNA strand is: T-C-A-T-G-G-C-T-A-T-G-C-T-A-A-A-T-G-C.

Calculating the Mass and Length of DNA

To calculate the mass and length of DNA, we need to know the average molecular weight of a nucleotide. The average molecular weight of a nucleotide is approximately 330 Daltons (Da).

The given DNA fragment has 19 nucleotides. Therefore, the mass of the DNA fragment can be calculated as follows:

Mass = Number of nucleotides * Average molecular weight of a nucleotide = 19 * 330 Da = 6270 Da

The mass of the DNA fragment is 6270 Daltons.

To calculate the length of the DNA fragment, we count the number of base pairs. Since each base pair corresponds to one nucleotide, the length of the DNA fragment is also 19 base pairs.

Counting Hydrogen Bonds

To count the number of hydrogen bonds in the given DNA fragment, we need to consider the base pairing rules. Adenine (A) forms two hydrogen bonds with thymine (T), while cytosine (C) forms three hydrogen bonds with guanine (G).

The given DNA fragment contains the following base pairs: A-T, G-C, A-T, C-G, A-T, T-A, C-G

Counting the number of hydrogen bonds: A-T: 2 hydrogen bonds G-C: 3 hydrogen bonds A-T: 2 hydrogen bonds C-G: 3 hydrogen bonds A-T: 2 hydrogen bonds T-A: 2 hydrogen bonds C-G: 3 hydrogen bonds

Total number of hydrogen bonds = 2 + 3 + 2 + 3 + 2 + 2 + 3 = 17 hydrogen bonds.

Building the Informational DNA

To build the informational DNA, we need to convert the given DNA fragment into RNA. In RNA, adenine (A) pairs with uracil (U), and cytosine (C) pairs with guanine (G).

The given DNA fragment is: A-G-T-A-C-C-G-A-T-A-C-G-A-T-T-T-A-C-G

To convert it into RNA, we replace each thymine (T) with uracil (U):

A-G-U-A-C-C-G-A-U-A-C-G-A-U-U-U-A-C-G

The informational DNA is: A-G-U-A-C-C-G-A-U-A-C-G-A-U-U-U-A-C-G.

Note: The informational DNA is actually RNA, as it contains uracil (U) instead of thymine (T).

Finding the Number of Other Nucleotides

In the given DNA, it is mentioned that there are 880 guanine (G) nucleotides, which constitute 22% of the total number of nucleotides.

To find the number of other nucleotides (A, T, C), we can calculate the percentage of each nucleotide and then find the actual count.

Since guanine (G) constitutes 22% of the total nucleotides, the remaining nucleotides (A, T, C) constitute 78% (100% - 22%) of the total nucleotides.

To find the count of other nucleotides, we can use the following formula:

Count of nucleotide = (Percentage of nucleotide / 100) * Total number of nucleotides

For example, to find the count of adenine (A) nucleotides:

Count of adenine (A) = (Percentage of adenine (A) / 100) * Total number of nucleotides = (78 / 100) * Total number of nucleotides

Similarly, we can calculate the count of thymine (T) and cytosine (C) nucleotides using the same formula.

Unfortunately, the total number of nucleotides in the given DNA is not provided, so we cannot calculate the actual count of other nucleotides.

Conclusion

In summary: - The second DNA strand based on the given fragment is T-C-A-T-G-G-C-T-A-T-G-C-T-A-A-A-T-G-C. - The mass of the DNA fragment is 6270 Daltons, and its length is 19 base pairs. - The given DNA fragment has 17 hydrogen bonds. - The informational DNA, converted from the given DNA fragment, is A-G-U-A-C-C-G-A-U-A-C-G-A-U-U-U-A-C-G. - The actual count of other nucleotides (A, T, C) cannot be determined without the total number of nucleotides in the DNA.

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