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Figure 14 shows a banana plantation - Edexcel - GCSE Biology - Question 9 - 2020 - Paper 1
Question 9
Figure 14 shows a banana plantation. After the bananas have been harvested, the old plants are cut down. The suckers then develop into mature plants producing the n... show full transcript
Worked Solution & Example Answer:Figure 14 shows a banana plantation - Edexcel - GCSE Biology - Question 9 - 2020 - Paper 1
Step 1
Describe the function of a meristem in the growth of a plant.
Answer
A meristem is a region of undifferentiated cells in a plant that is capable of cell division and growth. The main functions of meristem cells include:
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Cell Division: Meristem cells can divide by mitosis to produce new cells, contributing to the overall growth of the plant.
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Differentiation: These cells remain undifferentiated, allowing them to give rise to various specialized cell types, which is crucial for the development of different plant tissues.
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Growth: Meristems are responsible for primary growth (lengthening) and secondary growth (thickening) in plants, enabling the plant to increase its height and girth.
Step 2
Describe how the student would prepare a microscope slide using these cells.
Answer
To prepare a microscope slide using cells from the meristem, the student should follow these steps:
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Obtain a Sample: Use a sharp blade to cut a thin slice of the meristem tissue, ensuring the sample is very small for optimal viewing.
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Mount the Sample: Place the thin slice on a clean microscope slide.
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Add a Stain: If necessary, apply a drop of suitable staining solution to enhance contrast and make the cells more visible under the microscope.
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Cover with a Coverslip: Gently lower a coverslip over the sample to avoid air bubbles, which could obstruct the view.
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Observe under the Microscope: Finally, place the slide under the microscope and adjust the focus to observe the cells.
Step 4
Step 5
Describe the structure of DNA and how it can be extracted from plant cells.
Answer
DNA is structured as a double helix, consisting of two long strands composed of nucleotides. Each nucleotide includes a deoxyribose sugar, a phosphate group, and one of four nitrogenous bases (adenine, thymine, cytosine, or guanine).
To extract DNA from plant cells, the following steps can be performed:
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Cell Lysis: Mash the plant tissue in a buffer solution containing a detergent to break down the cell membranes and release cellular components.
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Remove Proteins: Add a protease enzyme to digest proteins that are bound to the DNA and precipitate them out of the solution.
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Precipitate DNA: Add cold alcohol (ethanol or isopropanol) to the solution, which causes the DNA to precipitate out, as it is soluble in water but not in alcohol.
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Collect DNA: The precipitated DNA can then be spooled out using a rod or pipette and rinsed with alcohol to purify it further.