Chapter 7: Transport in Plants Flashcards
Why do plants not need a high surface area to volume ratio?
Thay has very extensive root networks that only need simple diffusion. It is not as compact as animal cells are.
What are the main reasons for why transport is important in plants?
- To move absorbed substances to where they are needed.
- To move produced substances like glucose from e where they are produced to where they are needed.
- To move substances to their respective storage organs.
How are plants adapted for maximum oxygen absorption?
they are flat and have large surface areas.
Why do plants not need any complex transport mechanisms for oxygen transport?
The branching nature of the plant provides sufficient surface area. The oxygen is a waste product of photosynthesis.
What is the xylem?
It is the plant tissue that carries water and mineral ions from the roots to the cells. It works in 2 directions.
What is the phloem?
It is the plant tissue that carried the products of photosynthesis to the other parts of the plant.
What is the parenchyma?
It is the cellular tissue, typically soft and succulent found chiefly in the softer parts of the leaves, pulp of fruits, bark and pith of stems.
What is the function of of the parenchyma cells.
They function in storage and photosynthesis and as the bulk of ground and vascular tissues.
Describe the activity of parenchyma cells.
They are very metabolically active
What are the collenchyma cells?
They are cells that are similar to parenchyma, but have cellulose deposits which makes them stronger
Where do we find the collenchyma cells?
In the midrib
What is the endodermis?
It is the inner layer of cells in the cortex of a root and some stems surrounding a vascular bundle.
How does the endodermis prevents water from seeping through?
It has an impermeable ring of Suberin around it to form the Casparian strip that prevents water from seeping through.
What is Suberin?
It is an impermeable and inner waxy substance in the cell wall of corky tissue.
What is the nature of the casparian strip?
it is hydrophobic
What are mesophyll cells?
They are a type of specialised parenchyma cells that are able to photosynthesise.
What are the two types of mesophyll cells?
Palisade and Spongy
What is the pericycle?
It is a thin layer of plant tissue between the endodermis and phloem that encircles the vascular tissue.
What is a feature of the pericycle and its respective function due to that feature?
It is meristematic
It allows lateral root initiation and allows for secondary root growth
What is the pericycle cells made of?
Parenchyma and Sclerenchyma
Describe the xylem vessel
The xylem is made of cells called xylem vessel elements, which are reinforced by lignin.
What are the functions of xylem vessels?
They transport water through long distances and give the plant mechanical strength
What is a vascular bundle?
It is a bundle like structure formed by the xylem and phloem.
What is the function of sclerenchyma fibres?
They provide support to the xylem vessels due to their lignified nature.