Question

Бактериальная клетка стандартного объёма (цилиндр высотой 5 мкм и радиусом 1 мкм) содержит примерно 15 тысяч рибосом. Масса одной рибосомы x 2, 3 х 10° да. Каждая рибосома примерно на 35% состоит из белка и на 65% из РНК. Сколько молекул рРНК, находящихся в составе рибосом, присутствует в L-форме бактерии (бактериальная клетка без клеточной стенки, имеет форму шара радиусом 1,5 мкм)? В ответе укажите число с точностью до целых.

Answer 1

Ответ:

40500

Объяснение:

Answer 2

Calculation of the Number of rRNA Molecules in a Bacterial Cell

To calculate the number of rRNA molecules in a bacterial cell, we need to consider the following information:

- The bacterial cell is in the shape of a sphere with a radius of 1.5 μm. - The bacterial cell does not have a cell wall. - The bacterial cell contains approximately 15,000 ribosomes. - The mass of one ribosome is 2.3 x 10^(-19) g. - Each ribosome is approximately 35% protein and 65% RNA.

Let's break down the calculation step by step:

1. Calculate the volume of the bacterial cell: - The volume of a sphere can be calculated using the formula V = (4/3)πr^3, where r is the radius of the sphere. - Substituting the given radius of 1.5 μm into the formula, we get V = (4/3)π(1.5 μm)^3. - Calculating the volume, we find V ≈ 14.137 μm^3.

2. Calculate the mass of all the ribosomes in the bacterial cell: - The mass of one ribosome is given as 2.3 x 10^(-19) g. - Multiplying the mass of one ribosome by the total number of ribosomes (15,000), we get the total mass of ribosomes in the bacterial cell: (2.3 x 10^(-19) g) x (15,000) = 3.45 x 10^(-15) g.

3. Calculate the mass of RNA in the ribosomes: - Each ribosome is approximately 65% RNA. - Multiplying the total mass of ribosomes by 65%, we find the mass of RNA in the ribosomes: (3.45 x 10^(-15) g) x 0.65 = 2.2425 x 10^(-15) g.

4. Calculate the number of rRNA molecules: - The mass of RNA in the ribosomes is given as 2.2425 x 10^(-15) g. - To calculate the number of rRNA molecules, we need to convert the mass of RNA to moles using the molar mass of RNA. - The molar mass of RNA is approximately 3.2 x 10^6 g/mol. - Dividing the mass of RNA by the molar mass, we find the number of moles of RNA: (2.2425 x 10^(-15) g) / (3.2 x 10^6 g/mol) ≈ 7.008 x 10^(-22) mol.

- Finally, we can use Avogadro's number (6.022 x 10^23 molecules/mol) to convert moles to molecules: - Multiplying the number of moles of RNA by Avogadro's number, we find the number of rRNA molecules: (7.008 x 10^(-22) mol) x (6.022 x 10^23 molecules/mol) ≈ 4.218 x 10^2 molecules.

Therefore, the number of rRNA molecules in the L-form of the bacterial cell is approximately 421 (with no decimal places).