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Phloem transports sugar from where it is produced to where it is used via a pres

ID: 200251 • Letter: P

Question

Phloem transports sugar from where it is produced to where it is used via a pressure-flow mechanism. Select whether each of the following refers to a sugar source or sink.

A leaf on a summer day

Where phloem sap has its highest sugar concentration

Any photosynthesizing part of a plant

Where sugar leaves the phloem by active transport

Phloem sap flows toward this area

A growing bud (flower)

Source

Sink

____

A leaf on a summer day

____

Where phloem sap has its highest sugar concentration

____

Any photosynthesizing part of a plant

____

Where sugar leaves the phloem by active transport

____

Phloem sap flows toward this area

____

A growing bud (flower)

1.

Source

2.

Sink

Explanation / Answer

Question: Phloem transports sugar from where it is produced to where it is used via a pressure-flow mechanism. Select whether each of the following refers to a sugar source or sink.

Answer:

In plants, phloem transports sugars from sources, the region where it is produced to sinks, the areas where it is needed and used. The mechanism by which phloem transports sugar from the sources to the sinks is called pressure-flow. Sources include the photosynthesizing parts of a plant, usually the leaves. Sinks include the growing tissues. Within the phloem, sugars travel from areas of high sugar concentration, the sources to areas of low sugar concentration, the sinks. In the sources sugar moves into the phloem and sugar leaves the phloem in the sinks by active transport

Source (1):

Source (1) A leaf on a summer day Source (1) Where phloem sap has its highest sugar concentration Source (1) Any photosynthesizing part of a plant Sink (2) Where sugar leaves the phloem by active transport Sink (2) Phloem sap flows toward this area Sink (2) A growing bud (flower)