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

Deficiency diseases-post-parturient haemoglobinuria (pph), Post-parturient ...

Post-parturient haemoglobinuria (pph) in cattle and buffaloes The post-parturient haemoglobinuria (PPH) is an acute disease of high yielding buffaloes and cows. The disease oc

Explain synaptic transmission between neurons, Q. How does synaptic transmi...

Q. How does synaptic transmission between neurons take place? The propagation of the action potential along the axon reaches the region immediately anterior to the presynaptic

Can you define musculoskeletal system, Q. Which are the organs that are par...

Q. Which are the organs that are part of the musculoskeletal system? The key tissues and organs that are part of the musculoskeletal system in humans are the cartilages, the mu

Which germ layer originate liver and the pancreas, Q. From which germ layer...

Q. From which germ layer do the liver and the pancreas originate? What are other organs and tissues made from that germ layer? The pancreas and the liver are originated from th

Botany, what is affinites of gymnosperm

what is affinites of gymnosperm

How are the antibodies against the rh factor formed, How are the antibodies...

How are the antibodies against the Rh factor formed? Anti-Rh antibodies are made by humoral immune response. When an Rh- individual makes contact with the Rh factor this is rec

Stds, define stds give 5 examples of stds give signs, symptoms, treatment a...

define stds give 5 examples of stds give signs, symptoms, treatment and prevention of each example

Define the disc electrophoresis, Define the Disc Electrophoresis? Disc ...

Define the Disc Electrophoresis? Disc electrophoresis has improved resolution and strong bands are obtained. It requires a two-gel system and several different buffers. The run

Difference between a bird heart and a mammalian heart, What is the main dif...

What is the main difference between a bird heart and a mammalian heart? The bird heart has a one aortic arch on the right side of its body while the mammalian heart has one on

HOME, WHERE DOES LIZARD LIVE

WHERE DOES LIZARD LIVE

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