Exam (elaborations)
CHAPTER-11 TRANSPORT IN PLANTS
- Course
- Institution
CHAPTER-11 TRANSPORT IN PLANTS
[Show more]
Content preview
CBSE Quick Revision Notes (Class-11 Biology)CHAPTER-11 TRANSPORT IN PLANTS
Plant transport various substance like gases, minerals, water, hormones, photosynthetes
and organic solutes to short distance (one cell to another) or long distance as water from
roots to tips of stem.
• Long distance transport occurs through vascular system, xylem and phloem called
translocation through mass flow.
• The direction of translocation may be unidirectional as in case of water and
multidirectional as in minerals and organic solutes.
Means of Transport
Simple Diffusion Facilitated Diffusion Active Transport
Simple Diffusion-
• Movement by diffusion is passive and slow along the concentration
gradient through permeable membrane.
• No energy expenditure takes place. It occurs in liquid and gases.
• Rate of diffusion are affected by gradient of concentration, permeability
of membrane, temperature and pressure.
Facilitated Diffusion-
• Lipid soluble particles easily pass through cell membrane but the
hydrophilic solutes movement is facilitated.
• For facilitated diffusion, membrane possesses aquaporins or water
channels. Aquaporins are membrane proteins for passive transport
of water soluble substances without utilization of energy.
• The protein forms channels in membrane for molecules to pass
through. The porins are proteins that forms huge pores in the
outer membrane of the plastids, mitochondria etc.
• Water channels are made up of eight different types of aquaporins.
Symport, Antiport and Uniport-
In Symport, both molecules cross the membrane in the same
direction.
In Antiport, both molecules moves in opposite direction.
When a molecule moves across a membrane independent of other
molecules, the process is called uniport.
Active Transport
• Uses energy to pump molecules against the concentration gradient. It is carried out by
membrane proteins.
Portal for CBSE Notes, Test Papers, Sample Papers, Tips and Tricks
, • In active transport movable carrier proteins are called pumps.
• The pumps can transport substance from low concentration to high concentration. The
carrier proteins are very specific in what it carries across the membrane.
Comparison between Transport mechanisms-
Simple diffusion Facilitated diffusion Active transport
Special membrane protein Special membrane protein Special membrane protein
is not required. is required. is required.
Not selective Highly selective Highly selective
Transport do not saturate Transport saturate Transport saturate
No uphill transport Uphill transport Uphill transport
No ATP energy is required. No ATP energy is required. ATP energy is required.
Plant Water Relationship
Water is essential for all physiological activities of plants along with all living organisms. It
provide medium for most substances to dissolve in it.
Protoplasm of cells contains water in which different molecules are dissolved and
suspended.
Terrestrial plants take lot of water and release most of it in form of water vapour by the
process of transpiration.
Water is the limiting factor for plant growth and productivity in both agricultural and
natural environments.
Water Potential (Ψw)- is a concept fundamental to the understanding water movement.
Water potential is determined by solute potential (Ψs) and pressure potential (Ψp).
Water molecules possess kinetic energy. The greater the concentration of water in the
system, the greater is its kinetic energy or water potential. So pure water has greatest
water potential.
Water potential is denoted by Greek symbol Psi (Ψ) and is expressed in pressure unit
Pascal (Pa).
Water pressure of pure water is taken as zero at standard temperature and pressure. A
solution has less water potential due to less water concentration.
The magnitude of lowering of water potential due to dissolution of solute is called solute
potential (Ψs ). Solute potential is always negative. More the solute molecules in the
solution lesser the solute potential.
If a pressure greater than atmospheric pressure is applied to pure water or solution, its
water potential decreases. Pressure potential is usually positive. Pressure potential is
denoted by (Ψp).
Water potential of a cell is affected by both solute and pressure potential. The relationship
is as follows.
Portal for CBSE Notes, Test Papers, Sample Papers, Tips and Tricks
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller lennyjast. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $7.99. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
80364 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now