Chloroplasts, Biology

Assignment Help:

CHLOROPLASTS

  • Schimper (1883) coined the term chloroplastid for green plastids.
  • Mayer called them Autoplast. Chloroplast name proposed by Erera.
  • Green plastids with chlorophylls and other photosynthetic pigments.
  • Shape of chloroplasts vary in different plants.

Discoidal or oval    -           Higher plants

Girdle shaped        -           Ulothrix

Cup shaped           -           Chlamydomonas

Reticulate              -           Oedogonium

Spiral    -                             Spirogyra

Stellate                  -           Zygnema

  • Largest cell organelle in plants and second largest structure in plant.
  • Double unit membranous cell organelles.
  • Each chloroplast has two parts -

(i) Grana - Made up of Granum lamellae arranged in the form of stacks of coins. Each granum lamella is surrounded by well-defined membrane called Thylakoid (Thylakoid discovered by Menke). Each granum lamella, granular structures called Quantasomes are present. Quantasomes are photosynthetic units. (Quantasomes discovered by Park, Pon and Biggins) Each qunatasome has 230 chlorophyll molecules. Each chlorophyll molecule has two parts - head and tail. Head part is responsible for green colour which is controlled by Mg++. Due to presence of chlorophyll in granum lamellae, the light reaction of photosynthesis takes place in the granum. Lamellae which connects grana are called stroma thylakoids or fret channels (Weier 1966).

1863_chloroplast.png

(ii) Stroma - The non pigmented enzymatic part of chloroplast is called stroma. It is present in form of matrix. Due to presence of enzymes in stroma, dark reactions of photosynthesis take place here. Stroma contains osmophilic droplets called Plastoglobuli. These store lipids. Stoma of chloroplast contains proteins, phospholipids, nucleic acids, ribosome and fewer amounts of enzymes. Ris and Plaut, Ruthe sager discovered DNA in chloroplast, which is called ctDNA or plastidial DNA. Genetic system of chloroplast is called Plastidome. Due to presence of DNA, RNA and ribosomes chloroplast is called semiautonomous unit like mitochondria having a complete protein synthesis apparatus in stroma.


Related Discussions:- Chloroplasts

Describe how a phagocyte destroys bacteria, Describe how a phagocyte destro...

Describe how a phagocyte destroys bacteria. The phagocyte forms a pouch in its cell membrane and engulfs bacteria in the pouch. It then pinches off the pouch to produce a vesi

Tooth associated with persistent apical periodontitis, Tooth associated wit...

Tooth associated with Persistent apical periodontitis Functional retention of the tooth : persistent lesion while remain asymptomatic function for an extended period of time .

Define reaction of fehling solution with lactose, Define Reaction of Fehlin...

Define Reaction of Fehling solution with lactose? After complete reduction of cupric ions, the indicator is reduced by lactose to a leuco compound, restoring the red colour of

Slight or no metamorphosis, Slight or no Metamorphosis In primitive w...

Slight or no Metamorphosis In primitive wingless insects (Apterygota) such as spring tails, silver fish etc. and in secondarily apterous insects the young ones which hatch fr

Explain the analysis of food production, Explain the Analysis of food produ...

Explain the Analysis of food production? The agricultural sector is known for its diversity and heterogeneity of decisions right from the farm to the entire marketing system. A

Fats requirements during congestive cardiac failure, Q. Fats requirements d...

Q. Fats requirements during congestive cardiac failure? Fat: The quantity and quality of fat would be governed by the severity of hyper- lipidemia and adiposity. Emphasis, as

In which part of the digestive tube is water is absorbed, Q. In which part ...

Q. In which part of the digestive tube is water is chiefly absorbed? What about the mineral ions and vitamins? Most part of water, mineral and vitamins ions are absorbed by the

How do organisms adjust to changes in temperature, How do organisms adjust ...

How do organisms adjust to changes in temperature? Some of the most ordinary way for an organism to adjust to changes in body temperature is by perspiration or panting.

Project, occurrence of e.coli 0157:H7 on vegetables

occurrence of e.coli 0157:H7 on vegetables

Lymph capillaries, Normal 0 false false false EN-IN X...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

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