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

Plastids, Plastids The term plastid first used by Haeckel (1865). ...

Plastids The term plastid first used by Haeckel (1865). These are present in plants and few protists (Euglena). On the basis of function plastids are of three types

Chloroplasts , Chloroplasts Like mitochondria, chloroplasts are also di...

Chloroplasts Like mitochondria, chloroplasts are also distinctive organelles of eucaryotic cell. But they are found only in plant cells. Chloroplasts contain membranes forming

Explain the absorption of protein, Explain the Absorption of Protein? A...

Explain the Absorption of Protein? Although single amino acids are liberated in the intestinal contents, there is insufficient power in the enzymes of the pancreatic juice to r

Determine organic material for the energetic metabolism, How are bacteria c...

How are bacteria classified according to the production of organic material for the energetic metabolism? Most bacteria are heterotroph, they do not produce their own food. The

Solubility of oxygen, Solubility of Oxygen It is also important to kno...

Solubility of Oxygen It is also important to know that solubility of gases decreases with the presence of solutes or increased salinity. Table shows the solubility of oxygen a

Procedure for estimation of vitamin c - colorimetric method, Define Procedu...

Define Procedure for estimation of vitamin c - colorimetric method? Carry out the experiment following the instructions given herewith: 1. Prepare a series of tubes for blan

What are the properties og gel, What are the properties og Gels? Polysa...

What are the properties og Gels? Polysaccharides, proteins or colloidal complex particles, such as caseinate micelles  form gels at levels of 10% or less. Gums, pectin and gela

Determine the concept of imitation in the learning process, Determine the c...

Determine the concept of  imitation in the learning process The concept of  imitation in the learning process is also a key developmental concept for infants and young children

Define prognosis of eating disorders, Define Prognosis of Eating Disorders?...

Define Prognosis of Eating Disorders? About 50% of the patients recover fully from anorexia nervosa and achieve normal weight, 30% improve but have a partial recovery and 20% w

Explain le compte operation-rev procedure, Explain Le Compte Operation-REV ...

Explain Le Compte Operation-REV Procedure ? This is an alternative type of repair for TGA, VSD and left ventricular outflow obstruction (LVOTQ). In this operation an extrinsic

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