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

Secondary induction, Secondary Induction The two primary inductive ev...

Secondary Induction The two primary inductive events that we have described so far are significant in the patterning of early embryo. But there are another such signaling eve

Would induction of CYP 2E1 raise your blood alcohol level?, If I take a dru...

If I take a drug that induced the synthesis of CYP 2E1 in my system, would that raise or lower my blood alcohol level after I drink a beer or wine (compared to if I hadn''t taken t

Motor control in annelids and arthropods, Motor Control in Annelids and Art...

Motor Control in Annelids and Arthropods In annelids and arthropods generally, individual metameric ganglia of the ventral nerve cord are capable of initiating and keep locomo

Enumerate the term - brain behaviour functioning, Enumerate the term - brai...

Enumerate the term - brain behaviour functioning The brain may be thought of as a "dependant variable" that is shaped in part by the facilitative stimulation that is experience

Non-protein amino acids, NON-PROTEI N AMINO ACIDS Non-protein amino ac...

NON-PROTEI N AMINO ACIDS Non-protein amino acids are the ones which are not incorporated in proteins but occur freely or in combined state in non-protein substances. Their

Digestive system - pharynx, PHARYN X - Commom system between digestive...

PHARYN X - Commom system between digestive system and respiratory system. In it gullet and glottis present.Gullet leads to oesophagus. Glottis lead to trachea. Wall of p

Explain the nasopalatine nerve and vessels, Nasopalatine nerve and vessels ...

Nasopalatine nerve and vessels Found in the nasopalatine canal, must be taken care off when placing implants in the maxillary incisor region. Subperiosteal implant placement o

Define characteristic of doppler echocardiographic, Q. Define characteristi...

Q. Define characteristic of Doppler Echocardiographic? Ans. Doppler findings of cardiac tarnponade are based on the following characteristic respiratory variations in intr

Explain salient features of pulmonary tuberculosis, Salient Features of pul...

Salient Features of pulmonary tuberculosis The salient features tuberculosis include: Wasting of tissues Exhaustion Cough Expectoration, and Fever The acute p

Hazard analysis, Hazard Analysis Two steps recognized as preliminary a...

Hazard Analysis Two steps recognized as preliminary and detailed analysis of hazard are taken. Preliminary Hazard Analysis (PHA) serves two aims: (i) It can expedite bringi

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