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

Fruits, how to do write the assaigment in botany give idea

how to do write the assaigment in botany give idea

Explain the infarct exclusive technique, Explain the Infarct Exclusive Tech...

Explain the Infarct Exclusive Technique? Infarct Exclusive Technique :  Left ventriculotomy is done through the infarcted area. No attempt is made to close the ventricu

Assuming that the two traits assort independent, In holly, serrated leaves ...

In holly, serrated leaves are dominant to smooth-edged leaves, and red berries are dominant to green berries. Two holly plants heterozygous for leaf edge shape and berry color are

How many respectively are genotypical and phenotypical forms, In F2 generat...

In F2 generation of a hybridization for a given trait conditioned by a pair of alleles T and t, according to Mendel's first law what are the genotypes of each phenotypical form? An

Explain about the smoking - methods of food processing, Explain about the S...

Explain about the Smoking - methods of food processing? Smoking was known as a method of food preservation at an early date. Foods are exposed to smokes by burning some special

Contagious bovine pleuropneumonia, C o n t a g i o u s bovine pleu...

C o n t a g i o u s bovine pleuropneumonia It is a disease of bovines characterized by high rise of body temperature and difficulty in respiration. E t iolo

Rhythm and conduction disturbances, Q. Rhythm and conduction disturbances? ...

Q. Rhythm and conduction disturbances? Alterations in cardiac rhythm occur frequently with exercise and are important in understanding a patients function and in providing pred

African swine fever, African swine fever African swine fever (ASF), a ...

African swine fever African swine fever (ASF), a highly contagious viral disease of swine and other porcine animals (generally confined to the African continent, part of Weste

Meiosis, What problem would most likely to occur if a haploid cell attempte...

What problem would most likely to occur if a haploid cell attempted to perform meiosis?

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