Which layer of the cell wall is formed first?
Correct answer: C. Middle lamella
- A. Primary wall
- B. Secondary wall
- C. Middle lamella
- D. Tertiary wall
Explanation
The cell wall of plants is composed of three main layers: the primary wall, the secondary wall, and the middle lamella. The middle lamella is first to be formed in between the primary walls of the neighboring cells. The primary wall is composed of cellulose and some deposition of pectin and hemicellulose. It is a true wall and develops in newly growing cells. The secondary wall is formed on its inner surface and is comparatively thick and rigid. The order of the cell wall layers growing inwards is: Middle lamella→Primary cell wall→Secondary cell wall.
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About Cell Structure and Function
Animal, plant, prokaryotic and eukaryotic cells are compared through their membranes, cell walls, nuclei and cytoplasmic organelles. The work includes the structures and functions of mitochondria, chloroplasts, ribosomes, endoplasmic reticulum, Golgi apparatus and lysosomes, as well as chromosome organization and the distinction between chromatin and chromosomes.
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