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

Define nutritional needs during exercise, Define Nutritional Needs during E...

Define Nutritional Needs during Exercise? During Exercise: Addressing the nutritional needs during training is essential for optimal performance. The focus should be to:

Neurulation in amphibians, Neurulation in Amphibians The first step i...

Neurulation in Amphibians The first step in the neurulation process is the flattening and thickening of dorsal ectoderm to form neural plate. The plate of cells are different

Radiolarians - protozoan, Radiolarians - Protozoan Radiolarians are en...

Radiolarians - Protozoan Radiolarians are entirely marine planktonic species with spherical bodies and radiating pseudopodia known as axopods. The spherical body is divided in

Explain evidence of coverage of ecology, Explain Evidence of coverage of Ec...

Explain Evidence of coverage of Ecology Evidence of coverage of Ecology and Evolution to the level of Descriptor 2 and an evaluation or  discussion that shows depth of underst

Explain microbiology of soil, Q. Explain microbiology of Soil? Ans. ...

Q. Explain microbiology of Soil? Ans. You would realize that the soil contains greatest varieties of microorganisms. It actually serves as a medium for growth and developm

Explain about the artificial sweeteners, Explain about the Artificial Sweet...

Explain about the Artificial Sweeteners? As a group, artificial sweeteners are classed as "non-nutritive". Thus, they provide sweet sensation to the tastebuds, with no increasi

What is the activation center of an enzyme, What is the activation center o...

What is the activation center of an enzyme? Is it the key or the lock of the lock and key model? The activation center is a region of the enzyme formed by its spatial conformat

Poultry and duck diseases-hydropericardium syndrome, Hydropericardium syndr...

Hydropericardium syndrome Hydropericardium syndrome (HPS), known as Leechi disease, is caused by Avian Adenovirus 4. HPS has been responsible for high mortality ranging from 6

Are the following statements true for eukaryotes, Are the following stateme...

Are the following statements true for eukaryotes , prokaryotes, both groups, or neither group? Answer They use a deoxyribonucleoside triphosphate as their energy currency"D They us

Define aortic regurgitation, Q. Define Aortic regurgitation? Aortic reg...

Q. Define Aortic regurgitation? Aortic regurgitation is a common valvular disease that may present chronically or acutely. Normally the integrity of valve closure depends upon

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