Question

Which component of cell wall is normally in contact with plasmalemma?

• A. Primary wall
• B. Secondary wall
• C. Plasmodesmata
• D. Middle lamella.

Answer 1

Answer: (B)

Secondary wall

• A cell wall is a tough and flexible structural layer that surrounds cell membrane in plants, algae and most prokaryotes.
  
• The three important layers of a cell wall are:-

1. The primary cell wall is the first outermost thin, flexible and extensible layer.
2. The secondary cell wall is a thick layer present inside the primary cell wall which is in contact with the cell membrane or plasmalemma.
3. The middle lamella is a layer rich in pectins which cement the cell walls of adjacent plant cells and forms plasmodesmata (channels for communication between cells).

• So, the correct answer is 'Secondary wall'.