Transport through the phloem(1)

The phloem transport materials from ……………

• mesophyl cells to companion cells
• mesophyl cells to cortex cells
• companion cells to cortex cells
• companion cells to xylem vessel elements

Which of the following cannot function as a source?

• mesophyl cells of the leaves
• cortex cells of the root
• root hair cells of the root
• companion cells of the leaves

Which of the following cannot function as a sink?

• growing bud of a plant
• cortical cells of the root
• xylem vessel element
• mesophyl cells of the leaf

Assimilates transported by the plant phloem includes the following except ………………..

• amino acids
• sucrose
• glucose
• vitamins

Which of the following is processes is not involved in the transport of sucrose from the leaves to the roots?

• active transport
• osmosis
• facilitated diffusion
• endocytosis

Transport of sucrose from the companion cell into the neighbouring sieve tube elements is through the following except …………………………….

• by diffusion through the plasmodesmata
• by diffusion through cotransport proteins
• by active transport through proton pumps
• by mass flow through plasmodesmata

What commonly happens at the storage organs?

• unloading
• loading
• mass flow

A germinating seed contains stores of starch that can act as ……………………………….

• source of glucose
• sink of glucose
• photosynthetic tissue
• osmotic force

Why is loading described as an active process?

• ATP is required for the transport of sucrose through the plasmodesmata
• ATP is required for the transport of sucrose by cotransport proteins
• ATP is required for maintaining high proton gradient across the walls of the companion cells
• ATP is required for the transport of hydrogen ions along with sucrose

What causes hydrostatic pressure to build up within the phloem tissues close to the mesophyl cells

• entry of sucrose from the companion cells
• entry of water from the mesophyl cells
• entry of water from xylem vessels
• exit of water from sieve tube elements