Translocation

Open Ended

what nutrients are this insect trying to get?

Multiple Choice

Why is translocation important for plants?

• It helps in photosynthesis

• It enables the transport of water

• It allows movement of assimilates like sucrose from sources to sinks

• It provides structural support

Open Ended

Describe the structure and the function of the phloem vessel.

Multiple Choice

Which tissue is primarily responsible for the bidirectional transport of sugars and amino acids in plants?

• Xylem

• Phloem

• Cambium

• Epidermis

Fill in the Blank

Fill in the blank: Sucrose makes up ___% of phloem sap.

Open Ended

Explain the difference between a source and a sink in the context of plant translocation.

Multiple Choice

Which of the following plant parts can act as both a source and a sink?

• Leaf

• Flower

• Seed

• Apical meristem

Multiple Choice

Based on the carbohydrate content table, which plant part contains the highest amount of sucrose?

• Leaf blade

• Vascular bundle in the leaf stalk

• Tissue surrounding the vascular bundle

• Buds, roots, and tubers

Open Ended

Describe the process by which assimilates are loaded into the phloem, mentioning the two main routes.

Multiple Choice

Which of the following statements correctly describes the symplast route for assimilate movement in plants?

• Assimilates are stored in the vacuoles and moved through the cytoplasm via plasmodesmata in a passive process.

• Assimilates diffuse through the cell wall and are actively transported across the membrane.

• Hydrogen ions act as co-transporters to move assimilates across the membrane.

• Assimilates are moved by mass flow due to hydrostatic pressure.

Fill in the Blank

Fill in the blank: In the apoplast route, assimilates diffuse through the cell wall and intermembrane spaces before being actively transported into the sieve cells by _______.

Open Ended

Compare and contrast the symplast and apoplast routes for sucrose loading into the phloem. What are the key differences in their mechanisms?

Multiple Select

Which of the following are involved in the active movement of sucrose into a companion cell or sieve tube across the cell membrane?

• Proton pump

• Co-transporter

• ATP

• Plasmodesmata

Multiple Choice

Based on the diagrams, which route (apoplast or symplast) involves the movement of assimilates through plasmodesmata?

• Apoplast route

• Symplast route

• Both routes

• Neither route

Open Ended

Explain how mass flow in the phloem is driven by changes in water potential at the source and the sink.

Open Ended

Why might the theory of mass flow not be correct?

Open Ended

Explain how the evidence for mass flow suggests the theory is correct.

Multiple Choice

Which of the following is NOT evidence supporting the mass flow hypothesis in plants?

• Advances in microscopy show adaptations for active transport in companion cells.

• Poisoning mitochondria in companion cells stops translocation.

• The flow of sugars in the phloem is about 10,000 times faster than diffusion alone.

• All solutes in the phloem move at the same rate.

Multiple Choice

What happens to the distribution of sugars in a tree when a ring of bark is cut away from the trunk?

• Sugars collect below the ring.

• Sugars collect above the ring.

• Sugars are evenly distributed throughout the tree.

• Sugars stop moving entirely.

Multiple Choice

Which structures are directly involved in the translocation of sucrose in plants?

• Xylem vessels

• Phloem sieve tubes

• Root hairs

• Guard cells

Multiple Choice

Which of the following best describes the process of translocation in plants?

• Movement of water from roots to leaves through xylem

• Transport of assimilates, especially sucrose, in the phloem between sources and sinks

• Exchange of gases in the stomata

• Absorption of minerals from soil

Open Ended

Describe the pathways by which water passes from the soil to the cells of the cortex shown in Fig. 1.

Open Ended

With reference to Fig. 4.1, explain how sucrose travels from the source to cell C, and from cell C to the sink.

Multiple Choice

What are the main types of cells found in the phloem vessel?

• Sieve tube elements and companion cells

• Xylem vessels and tracheids

• Guard cells and epidermal cells

• Parenchyma and sclerenchyma

Open Ended

Summarize how translocation works in plants and why it is considered an energy-requiring process.