Which of the following illustrations shows the mitochondrion's structural…
2024
Which of the following illustrations shows the mitochondrion's structural details?
Answer: B. b — Concept: A mitochondrion is identified structurally by its double-membrane plan. A smooth outer membrane encloses the whole organelle, and a separate inner…
- A.
d
- B.
b
- C.
c
- D.
a
Attempted by 6 students.
Show answer & explanation
Correct answer: B
Concept: A mitochondrion is identified structurally by its double-membrane plan. A smooth outer membrane encloses the whole organelle, and a separate inner membrane lies within it; that inner membrane is thrown into repeated shelf- or ribbon-like folds called cristae, which project into the inner fluid space known as the matrix. Recognising an organelle from a drawing therefore means testing it against this defining architecture - two nested boundaries plus internal folding of the inner one - rather than judging by colour, size or overall outline.
Application: read each labelled illustration in the figure strip and test it against that architecture.
Label | What the drawing shows | Nested boundaries with internal folds? |
|---|---|---|
a | A flat panel with a uniform field carrying evenly spaced circles of equal size in a repeating grid | No - a single flat surface pattern within one outline |
b | A bean-shaped body cut open along one side, with an outer boundary, a second boundary just inside it, and that inner boundary folded into ribbon-like projections reaching into the interior | Yes - two nested boundaries and internal folds |
c | Rows of identical rectangular blocks separated by straight mortar lines, each row offset by half a block (a brick wall) | No - a repeating masonry pattern within one outline |
d | Small spheres joined by straight rods into linked six-membered rings drawn in perspective (a ball-and-stick lattice model) | No - an open framework with no enclosing boundary |
Cross-check: the three non-matching drawings are all repeating patterns or open models bounded by a single outline - a dot pattern, a masonry wall and an atomic ball-and-stick lattice - so none of them can supply the second, folded membrane that the definition requires. Only one drawing carries an outer boundary, a distinct inner boundary and cristae-like folds together.
Result: the illustration labelled b shows the mitochondrion's structural details - its double membrane and the cristae formed by the folded inner membrane.