Pits, Biology

Assignment Help:

PITS

  • Depressions in secondary cell wall is called pit.
  • A pit present on the free cell wall surface without its partner is called Blind pit.
  • It consists of 2 parts - Pit chamber and Pit membrane.
  • Pit chamber / pit cavity is depression in wall where secondary wall is absent.
  • Opening of pit chamber into cell is called pit pore / aperture.
  • Pit membrane is formed of (PCW + middle lamella + PCW) it is "trilaminar".
  • Pit membrane also called closing membrane.
  • Pit membrane is permeable due to permeability of primary cell wall.
  • Pits are of 2 types (depending upon the shape of the pit chamber.)

1318_pits.png

(i) Simple pit

  • Pit chamber has uniform width.
  • Diameter of lumen remains the same.
  • Found in vessels, tracheids & sclerenchyma.

(ii) Bordered pit

  • Pit chamber is flask-shaped.
  • Diameter of lumen is increases from inner to outer side.
  • A disc-shaped thickening called Torus is present in the middle of pit chamber on pit membrane.
  • It controls diffusion, it prevents rupturing of pit membrane when unequal pressure is present on its both sides.

1106_pits 1.png


Related Discussions:- Pits

How boiling used for sterilization, Q. How Boiling used for sterilization? ...

Q. How Boiling used for sterilization? Though highly unreliable as a sterilization technique and more effective for disinfection, it is used very often. Boiling water in hot wa

The best absorbed in an acidic environment, Why is a weekly acidic drug bes...

Why is a weekly acidic drug best absorbed in an acidic environment?

Bio-security in relation to diseases, B i o-security in relation to disea...

B i o-security in relation to diseases Bio-security is a strategic and integrated approach encompassing policy and regulatory frameworks to analyze and manage risks in the se

Functions of stomata, Functions of Stomata The cuticle forms outermost...

Functions of Stomata The cuticle forms outermost surface of the leaf and offers resistance to the evaporation of water vapour and entry of carbon dioxide necessary for photosy

Explain advantages of using yeast as a source of protein, Organism:- Yeast ...

Organism:- Yeast Advantages Large size, hence separation from the culture medium is easy.  As the pH of the growth is towards acidic side, high amount of lysine is prod

Define protein requirements of children up to age of 2 years, Define protei...

Define protein requirements of children up to age of 2 years? Infants and children up to age of 2 years should consume about 40% energy from fat (i.e. 40 en%). Fat is an import

Phylum protozoa, What are some examples of organisms belonging to this phyl...

What are some examples of organisms belonging to this phylum? Please name them.

Explain in details aerobic respiration, Explain in details Aerobic Respirat...

Explain in details Aerobic Respiration? The pyruvate produced in glycolysis is further broken down in most organisms. This process, called aerobic respiration, requires gaseou

Determine the long buccal nerve, Long buccal nerve The long buccal nerv...

Long buccal nerve The long buccal nerve is a branch of the mandibular division of the trigeminal nerve which provides sensory innervation to the buccal gingiva and mucosa of th

Photosynthetically active radiation, Photosynthetically Active Radiation ...

Photosynthetically Active Radiation This is usually in direct proportion with the incident solar radiation, you know that tropic$ are probably the best illuminated part of the

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd