phloem Flashcards
What is the function of phloem and which way does it transport ?
The function of phloem is to transport sugars mainly sucrose up and down the plant
What does phloem tissue consist of?
Sieve tube elements, companion cells
Are sieve tubes true cells and are they living?
Sieve tubes are not true cells as they have no nucleus and very little cytoplasm, however they are living cells.
How do sieve tubes line up?
End to end to form a column with cross walls at intervals, these cross walls are known as sieve plates which are perforated by many pores to allow sap to run through (flow through)
What is sucrose dissolved in to form sap?
Water
Do sieve tubes have thick or thin walls?
Thin walls 5 or 6 sided
Wher do companion cells lie?
Between sieve tubes they have a large nucleus a dense cytoplasm and numerous mitochondria
Why do companion cells contain numerous mitochondria?
To produce ATP for active processes such as metabolic processes such as toto load sucrose into the sieve tube elements
The cytoplasm of companion cells and the sieve tube elements are linked through many what?
Plasmodesmata which are gaps in the walls allowing communication and the flow of minerals between the cells.
