Question

Guard cells differ from other epidermal cells in having

• A. Large vacuoles
• B. Cell wall
• C. Chloroplast with PEP-carboxylase enzyme
• D. Absence of mitochondria

Answer 1

The correct option is C Chloroplast with PEP-carboxylase enzyme

Cells of epidermal layer do not have chloroplast but a very important distinction is that the guard cells contain chloroplast. The guard cells chloroplast also contains the enzyme PEP carboxylase, which may be important in producing organic acids from carbon dioxide during the day time. The resultant organic acids may lead to inflow of potassium and consequent water movement into the guard cells, leading to gain in turgor of guard cells and opening of stomata.