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Leaf cells produce glucose - Edexcel - GCSE Biology - Question 3 - 2012 - Paper 1
Question 3
Leaf cells produce glucose. Plants can use glucose to make oils, cellulose and DNA. (a) (i) Oils are needed to make cell membranes. The diagram shows a plant cell... show full transcript
Worked Solution & Example Answer:Leaf cells produce glucose - Edexcel - GCSE Biology - Question 3 - 2012 - Paper 1
Step 1
Which label on the diagram shows the cell membrane?
Answer
The cell membrane is the structure that surrounds the plant cell, providing protection and support. In the diagram, the label that corresponds to the cell membrane is B. Therefore, I would place a cross (X) in the box next to label B.
Step 2
Describe the function of cell walls in plant cells.
Answer
Cell walls serve several important functions in plant cells:
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Structural Support: Cell walls provide rigidity and help maintain the shape of the plant cell, allowing plants to stand upright.
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Protection: They act as a barrier against pathogens and environmental stress, protecting the internal components of the cell.
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Regulation of Water Intake: Cell walls help regulate water absorption, ensuring that cells do not become overly bloated with water.
Step 3
Describe the structure of DNA.
Answer
DNA, or deoxyribonucleic acid, has a double-helix structure composed of two long strands that coil around each other. Each strand consists of a backbone made of sugar (deoxyribose) and phosphate groups. Attached to this backbone are nitrogenous bases (adenine, thymine, cytosine, and guanine) that pair specifically (adenine with thymine and cytosine with guanine) through hydrogen bonds. This base pairing is crucial for the replication of DNA and for encoding genetic information.