Phloem Transport Mechanisms and Functions

The video explains the function of phloem in plants, focusing on the transport of sucrose and amino acids from source to sink. It covers the concepts of source and sink, active loading of sucrose, osmosis, pressure gradients, and mass flow. The video also clarifies that transport can occur in both directions, depending on the plant's needs.

What is the primary function of phloem in plants?

• To transport water and minerals

• To transport sucrose and amino acids

• To provide structural support

• To absorb sunlight for photosynthesis

In the context of phloem transport, what is a 'source'?

• A part of the plant that absorbs sunlight

• A part of the plant that provides sucrose and amino acids

• A part of the plant that receives nutrients

• A part of the plant that stores water

Why are root cortex cells considered sinks in plants?

• They store excess water

• They have chloroplasts and perform photosynthesis

• They are located above ground

• They cannot synthesize sucrose and amino acids

What is the process called when sucrose is transported from the source into the phloem sieve tube?

• Passive diffusion

• Active loading

• Osmosis

• Facilitated transport

How does the active loading of sucrose affect the water potential in the phloem sieve tube?

• It has no effect on water potential

• It decreases the water potential

• It stabilizes the water potential

• It increases the water potential

What happens when water rushes into the phloem sieve tube by osmosis?

• The pressure inside the sieve tube increases

• The pressure inside the sieve tube decreases

• The sieve tube shrinks

• The sieve tube becomes impermeable

What is the term for the movement of water and solutes down a pressure gradient in the phloem?

• Mass flow

• Active transport

• Capillary action

• Diffusion

Where is sucrose unloaded in the phloem transport process?

• In the mesophyll cells

• At the source

• At the sink

• In the xylem

Can the transport of sucrose in phloem occur from bottom to top?

• Yes, it can occur in both directions

• No, it only occurs from top to bottom

• No, it only occurs in the xylem

• Yes, but only in certain plants

What remains consistent in phloem transport regardless of direction?

• The use of sunlight

• The presence of chloroplasts

• The involvement of xylem

• The process of active loading and mass flow