Transport System 2

What is the main component of phloem sap?

• Glucose

• Sucrose

• Fructose

• Starch

Answer explanation

The main component of phloem sap is sucrose, which is a type of sugar that is transported through the plant's vascular system.

Which plant organ is considered a sugar source?

• Seed

• Fruit

• Leaf

• Root

Answer explanation

The correct plant organ considered a sugar source is the Leaf, as it performs photosynthesis to produce sugars through the chlorophyll present in its cells.

What drives the flow of phloem sap between source and sink cells?

• Magnetic force

• Gravity

• Positive pressure

• Negative pressure

Answer explanation

Positive pressure is what drives the flow of phloem sap between source and sink cells.

How is sucrose loaded into the companion cells and sieve tubes element?

• Passive transport

• Diffusion

• Active transport

• Osmosis

Answer explanation

Sucrose is loaded into the companion cells and sieve tubes element through active transport, which requires energy to move molecules against their concentration gradient.

What happens to the water potential in the sieve tube compared to the xylem vessel?

• It is lower

• It is higher

• It is the same

• It fluctuates

Answer explanation

The water potential in the sieve tube is lower compared to the xylem vessel, causing water to flow from the xylem vessel to the sieve tube.

How is sucrose unloaded from the sieve tube into the root cells?

• Osmosis

• Diffusion

• Facilitated diffusion

• Active transport

Answer explanation

Sucrose is unloaded from the sieve tube into the root cells through diffusion, where it moves from an area of high concentration to low concentration.

What happens to the turgor pressure between the leaf (source) and the root (sink) during translocation?

• It becomes negative

• It remains constant

• It decreases

• It increases

Answer explanation

During translocation, turgor pressure increases from the leaf (source) to the root (sink) to facilitate the movement of nutrients and water.

What is the function of sugar at the sink?

• Convert to fat

• Convert to fiber

• Convert to starch

• Convert to protein

Answer explanation

The function of sugar at the sink is to convert to starch, not fat, fiber, or protein.

What is the main driving force for the translocation process?

• Active transport

• Turgor pressure

• Osmosis

• Diffusion

Answer explanation

The main driving force for the translocation process is turgor pressure, which is the pressure exerted by the fluid inside the cell against the cell wall, pushing the cell contents in a particular direction.

Which of the following is NOT considered a sugar sink in a plant?

• Seed

• Leaf

• Root

• Fruit

Answer explanation

The correct choice is Leaf because leaves are not considered sugar sinks in a plant. Sugar sinks are organs that store or use sugars, while leaves primarily produce and transport sugars.