2. (a) A scientist obtained a mass of 0.0062 nanograms of DNA from a diploid human cell. Calculate the mass of DNA the scientist should obtain from a haploid human cell. Give your answer in picograms. (1 nanogram = 1000 picograms) (b) A student used the method shown in Figure 3 to compare the mass of DNA extracted from strawberry fruit cells and from kiwi fruit cells. crush the fruit cells in a buffer solution filter to separate the soluble DNA from the cell fragments add ethanol (i) State why ethanol is used. (ii) State two variables the student needs to control when using this method to compare the mass of DNA from these two fruits. 1 2 (iii) The student repeated the experiment. Give one reason why. (c) Mitosis and meiosis are processes that produce new cells. Compare the outcomes of mitosis and meiosis.

GCSE Edexcel Biology Meiosis – sexual reproduction: 2. (a) A scientist obtained a ma

2. (a) A scientist obtained a mass of 0.0062 nanograms of DNA from a diploid human cell - Edexcel - GCSE Biology - Question 2 - 2019 - Paper 1

Question 2

2. (a) A scientist obtained a mass of 0.0062 nanograms of DNA from a diploid human cell. Calculate the mass of DNA the scientist should obtain from a haploid human c... show full transcript

Worked Solution & Example Answer:2. (a) A scientist obtained a mass of 0.0062 nanograms of DNA from a diploid human cell - Edexcel - GCSE Biology - Question 2 - 2019 - Paper 1

Step 1

Calculate the mass of DNA from a haploid human cell

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Answer

To find the mass of DNA from a haploid cell, we first need to recognize that a diploid human cell contains two sets of chromosomes, while a haploid cell contains one. Therefore, we can calculate the amount of DNA in a haploid cell by dividing the mass of DNA from the diploid cell by 2.

Starting with the provided mass:

$\text{Mass of DNA from diploid cell} = 0.0062 \text{ nanograms}$

The mass of DNA from a haploid human cell is:

$\frac{0.0062}{2} = 0.0031 \text{ nanograms}$

To convert this value to picograms:

$0.0031 \text{ nanograms} \times 1000 = 3.1 \text{ picograms}$

Thus, the mass of DNA from a haploid human cell is 3.1 picograms.

Step 2

State why ethanol is used.

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Answer

Ethanol is used to precipitate the DNA. This allows the DNA to become visible, as DNA is not soluble in ethanol.

Step 3

State two variables the student needs to control when using this method to compare the mass of DNA from these two fruits.

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Answer

Mass of fruit
Volume of buffer

Step 4

Give one reason why the student repeated the experiment.

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Answer

The student repeated the experiment to ensure accuracy and reliability of the results.

Step 5

Compare the outcomes of mitosis and meiosis.

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Answer

Mitosis and meiosis are two distinct forms of cell division:

Mitosis results in two daughter cells that are genetically identical to the parent cell and to each other. It is used for growth, repair, and asexual reproduction.
Meiosis, on the other hand, produces four daughter cells that are genetically diverse, each containing half the number of chromosomes (haploid). It is essential for sexual reproduction and contributes to genetic variation in a population.

2. (a) A scientist obtained a mass of 0.0062 nanograms of DNA from a diploid human cell - Edexcel - GCSE Biology - Question 2 - 2019 - Paper 1

Worked Solution & Example Answer:2. (a) A scientist obtained a mass of 0.0062 nanograms of DNA from a diploid human cell - Edexcel - GCSE Biology - Question 2 - 2019 - Paper 1

Calculate the mass of DNA from a haploid human cell

State why ethanol is used.

State two variables the student needs to control when using this method to compare the mass of DNA from these two fruits.

Give one reason why the student repeated the experiment.

Compare the outcomes of mitosis and meiosis.

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