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

Mounting boxes for insect collections, Mounting boxes for insect collection...

Mounting boxes for insect collections Wood or cardboard cigar boxes make very useful and suitable housings for insect collections. After the insect has been separate from the s

Explain waste produced during surgical process, Q. Explain Waste produced d...

Q. Explain Waste produced during surgical process? Some of the waste products produced during a surgical process are dressings, sponges, gloves or other soft material dripping

#title.germ cell development, Ask questionhow are germ cells immortal #Mini...

Ask questionhow are germ cells immortal #Minimum 100 words accepted#

Characteristics of female''s skeleton, CHARACTERISTICS OF FEMALE'S SKELETON...

CHARACTERISTICS OF FEMALE'S SKELETON - 1.      Skull is lighter. 2.      Shoulders are nanow. 3.      Sacrum is shorter but wider. 4.      Pelvis is wider. 5.

Explain digestion and of digestive system of platyhelminthes, Q What are th...

Q What are the kinds of digestion and of digestive system of platyhelminthes? Flatworms have incomplete digestive systems and they present intracellular and extracellular compl

Define recommended dietary allowances for vitamin d, Define Recommended Die...

Define Recommended Dietary Allowances for Vitamin D? The recommendations of vitamin D are expressed as IU. 1 IU is defined as the activity contained in 0.025 mcg of cholecalci

Explain the principle of alkaline copper reduction method, Explain the Prin...

Explain the Principle of alkaline copper reduction method? All sugars which contain a free aldehyde group undergo enolization when placed in hot alkaline solution. This propert

Determine in brief about the mse, Determine in brief about the MSE The ...

Determine in brief about the MSE The MSE deals with questions concerning the addressee's Consciousness, Emotional State, Thought Content and Clarity, Memory, Sensory Perception

Show the use of incineration for sterilization, Q. Show the Use of Incinera...

Q. Show the Use of Incineration for sterilization? This is an excellent method for rapidly destroying materials such as soiled dressings, animal carcasses, bedding and patholog

Explain the phase contrast microscope, Explain the Phase Contrast Microscop...

Explain the Phase Contrast Microscop? Unpigmented and unstained living cells can be easily observed by phase contrast microscope. It has a special objective and a condenser th

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