Fig. 3.1 shows a single animal cell that was taken from the moist lining on the inside of a mammal's cheek. Cells of this kind are easy to collect gently an...
Question 1 Report
Fig. 3.1 shows a single animal cell that was taken from the moist lining on the inside of a mammal's cheek. Cells of this kind are easy to collect gently and are often used as an example of a typical animal cell when studying cell structure. Before being examined under a light microscope, the cell was treated with a stain, which colours certain parts so that they stand out clearly and can be told apart from one another. The cell has a rounded, irregular outline and does not keep a fixed shape. Four of its parts have been labelled with the letters A to D. Some of these parts are found in the cells of both plants and animals, while a plant cell of the same size would also contain one or two extra structures that this animal cell does not have.
Fig. 3.1
(a) State two functions of the structure labelled B. [2]
(b) State the function of the structure labelled A. [2]
(c) Describe the function of the structures labelled D. [2]
(d) State two structures found in a palisade cell but not shown in Fig. 3.1. [2]
Answer Details
This question tests animal cell structure using labelled parts of a cheek cell (A to D).
From the diagram: A is the outer boundary (cell membrane), B is the large round structure with a dark spot (nucleus), C is the jelly filling (cytoplasm) and the small oval bodies D are the mitochondria.
(a) Two functions of B (nucleus). [2] Any two of: it controls the activities of the cell; it contains the genetic material/DNA/chromosomes; it controls cell division [2, 1 each].
(b) Function of A (cell membrane). [2] It controls what enters and leaves the cell [1] because it is partially (selectively) permeable [1].
(c) Function of D (mitochondria). [2] They are the site of aerobic respiration [1], which releases energy for the cell [1].
(d) Two structures in a palisade cell not shown here. [2] Any two of: cell wall; chloroplast(s); a large permanent vacuole [2, 1 each]. Exam tip: these three are the plant-only extras; the mitochondria and nucleus are common to both, so they do not score here.
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