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

Cell cycle, The cell cycle undergoes a sequence of changes which invol...

The cell cycle undergoes a sequence of changes which involve a period of growth replication of DNA, Followed by cell division. This sequence of changes is called cell cycle.

Veterinary medicine have to do with physiology, What does veterinary medici...

What does veterinary medicine have to do with physiology and biochemistry? A lot of Physiology will teach about the function of animals and their parts. This is very significan

Name the alloys which are commonly used, Name the alloys which are commonly...

Name the alloys which are commonly used The most commonly used alloys are Ti-6Al-4V and Ti-6Al-4V extra low interstitial (ELI). Commercially pure Titanium comes in different gr

Organisational behaviour of health care, Organisational Behaviour of Health...

Organisational Behaviour of Health Care The insights provided by the theories of organisational behaviour emphasise the need for the establishment of institutional frameworks

Define functions of calcium in human body, Define Functions of Calcium in H...

Define Functions of Calcium in Human Body? Calcium salts provide rigidity to the skeleton and calcium ions play a role in many if not most, metabolic processes. In the vertebra

Physical and chemical factors that affect the pasteurization, Define the Ph...

Define the Physical and Chemical Factors That Affect the Pasteurization? There are a few other physical and chemical factors that affect the pasteurization method. These involv

Determine the strengths of full battery measures, Determine the Strengths o...

Determine the Strengths of Full Battery Measures 1) Wide range of scores allow differential diagnosis in various cognitive disorders 2) More reliable, and sensitive 3) Br

What is light microscope, Question Write a short note on the followin...

Question Write a short note on the following - 1 Plastids 2 Phagocytosis 3 Ribosomal subunits 4 Microfilaments 5 Cell cycle control 6 Tight junctions 7 W

Medical management of chronic renal failure, Medical Management   In ch...

Medical Management   In chronic  renal failure  there  is irreversible renal failure. The goals of medical management are:   To promote maximal  renal  function  To ma

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