Lecture 10 Flashcards
What is the success of plants dependent on?
Their ability to gather and conserve resources from the environment.
What has made long distance transport of water, minerals, and products of photosynthesis possible in plants?
Xylem and Phloem
What is Light Capture of plants dependent on?
Canopy structure- Phyllotaxy (the arrangement of the leaf)
What is the formula for the leaf area index (LAI)?
LAI= m^2 leaf/ m^2 ground
What is Nutrient Acquisition determined by in plants?
Structure of Roots; Proliferation in High Nutrient Zones; Symbiotic associations with mycorrhizal fungi. RPS
What are the mechanisms used for different distances of travel?
- Short-Distance: diffusion or active transport.
- Long-Distance: bulk flow.
How does the process of transportation begin in plants?
Begins with the absorption of resources by plant cells.
How is the movement of substances into and out of the cell regulated?
It is regulated by the selective permeability of the plasma membrane.
What are the three major pathways for transportation in plants?
Apoplastic-Symplastic-Transmembrane. TAS
Can water cross the cortex in plants? If so, how?
Yes, it can; it crosses the cortex via the symplast or apoplast.
What mechanism is used to block unwanted transportation of apoplastic material?
The waxy Casparian strip of the endodermis walls prevent the apoplastic transfer of minerals from the cortex to the vascular cylinder.
Diffusion across a membrane is what sort of movement?
Diffusion across a membrane is called passive transport.
Define Active Transport
The pumping of solutes across a membrane which requires energy (ATP)
Where do most solutes pass through when it comes to transportation?
Most solutes pass through the transport proteins embedded in the cell membrane.
What do Aquaporins do?
They channel water in and out of the cells.
What things can drive the transport of solutes into the cell?
The membrane potential (charge separation) and the proton gradient.
In ion channels, how are cations driven into the cell?
They are driven into the cell via membrane potential.
What does the membrane potential generated by proton pumps lead to in plants?
It contributes to the absorption of K+ by root cells.
When does co-transport occur?
It occurs when a transport protein couples the diffusion of one solute (H+ in the example) with the active transport of another (NO3- in the example)
What happens in a sucrose-H+ cotransporter?
It couples the movement of sucrose AGAINST its concentration gradient with the movement of H+ DOWN its concentration gradient.
What crucial thing must plants do in order to survive?
They must balance water uptake and loss.
What is the significance of Osmosis in plants?
It determines the net absorption or loss of water by a cell.
Define Water Potential
A measurements that combines the effects of solute concentration and pressure.
How do plants lose a large volume of water?
From transpiration, the evaporation of water from a plant’s surface.
