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Mitochondria-Plastid-Chloroplast | Notes-by-UK-Sir | Cell-Bio-10

CELL    (Mitochondria-Plastid-Chloroplast)

Plant Cell


Want to Know about Lysosome and Cytoskeleton:

https://uksirnotes.blogspot.com/2021/07/Lysosome-cytoskeleton-uksirnotes.html

Want to Know about Cytoplasm, RER, SER:

Want to Know about Transport in  Membrane:



Mitochondria

•      It is the Power house of cell.

•      Present in aerobic eukaryotes.

•      Related to respiration and production of energy.

•      Observed by Kolliker in 1880, and Coined by Benda (1897)

•      The Number differ from cell to cell.

•      May be 1 in unicellular eukaryote.

•      May be up to 2000 in Liver cell, up to 5 lakhs in Birds muscle cell.

•      Cylindrical or tubular shape, thread like structure.

•      Length 1.0- 4.1 μm and diameter 0.2-1.0 μm .

•      Contain- Protein 60-70 %, Lipids 25-35%, RNA 5-7%, DNA , Minerals, etc

Ultra Structure

Mitochondria
Mitochondria


•      Mitochondria is having a Double membrane system.

•      Thickness of the membrane is 60-75 A0

•      Outer membrane is - smooth and semi permeable, few lipid synthesis enzymes may present.

•      But Inner membrane is-highly selective.

•      Rich in double-phospholipid - cardiolipin , For which impermeable to ions.

•      Protein content high- 70-75%.

•      Inner membrane in folded to form involutions or projections – cristae.

•      Shape of cristae may be tubular (Plants), plate like (animals) or vesicle like (Euglena).

•      The Inner membrane contains number of – Elementary particle / F0-F1 particle / Oxysomes / ATPase molecule.

Cristae
Cristae


•      Number vary from - 1×104 to 105

•      Looks like a tennis racket - with head, stalk and base.

•      Base is F0 Unit- of size 11×1.5nm.  Act as rotor or motor.

•      Stalk is 5nm long.

•      Head (F1 Unit) - 8.5nm diameter included in ATP synthesis.

•      When H+ pass through, the F0-F1 particle produce ATP.

Outer Chamber/ space:

•      Between Outer and inner membrane a chamber or Inter membrane space present.

•      Also called Peri mitochondrial space.

•      It is 60-100 A0 wide.

•      It is having Fluid with few enzymes.

•      Sometime Outer and inner membrane come in contact – adhesion site.

•      It is Meant for transport.

Inner Chamber

•      Present at Central part of mitochondria.

•      Contain semi fluid matrix.

•      Matrix have – Protein, Ribosome , RNA, mitochondrial DNA, Enzymes of Krebs/ TCA cycle (except dehydrogenase of membrane), A.A, FA, Crystal of Calcium phosphate and Manganese.

•      Ribosomes- 70s in nature.

Semi-Autonomous Cell organelle:

•      These are believed to be symbionts –by  Margulis 1971.

•      It’s a semi-autonomous cell organelle.

•      It is with Own DNA ,with self-replication property.

•      Can Produce mRNA, tRNA, rRNA.

•      It is with its Own Ribosome system.

•      Can produce structural protein, enzymes.

•      Can grow internally and divide by Binary fission.

•      But it is dependent on the cell for survival.

Function:

•      It is Power House of cell- form ATP.

•      The Matrix-help in synthesis of F.A.

•      Involved in Synthesis of A.A.

•      Store and release calcium when necessary.

•      Provide intermediates for synthesis of chlorophyll, cytochrome, pyrimidine, steroids, alkaloids etc.

•      It show Maternal inheritance.

 


Plastids

•      The term was given by E. Haeckel in 1866.

•      These are Semiautonomous cell organelle store and synthesize various organic compounds.(food material)

•      Present only in plants.

•      Develop from colorless-  pro-plastids.

•      These are of 3 types:

•      Leucoplast, Chromoplast, Chloroplast

Types


Leucoplast


•      Colorless plastids, present in non green parts of plants.

•      Phtotosynthetic pigments are absent as grana absent.

•      Shape may be rounded, oval, cylindrical, fillamentous etc.

•      May be – Amyloplast (store starch)

•      Elaioplasts/ lipidoplast /Oleoplast (store Lipid)

•      Aleuroplast/ Proteoplasts/ Proteinoplast (Store Protein)

 

Chromoplast:

•      Colorful plastids (Yellow or reddish due to presence of carotenoids)

•      Chlorophyll absent here.

•      Develop from Chloroplast or Leucoplast.

•      Lamellae degenerate during formation of chromoplast.

•      During ripening of fruit – choromoplast formation from chloroplast.

•      Orange colour of carrot- due to carotene of chromoplast.

•      Provide colour to flower, fruit, also help membrane lipid synthesis.

Chloroplast :

•      It is green plastid with photosynthetic pigments.

•      Here synthesis of food occur from inorganic material with the help of radiation energy from sun.

•      Chloroplast other than green color- found in algae.

•      Rhodoplast- red algae, phaeoplast - Brown algae.

•      Number of chloroplast- 1 to many.

•      In leaf chlorenchyma - 20-40     but may be several hundreds- in Chara.

Shape-

•      Various shape- Plate like -Ulothrix, cup shaped- Chlamydomonas, ribbon shape- Spirogyra, Polygonal or stellate- Zygnema, Reticulate- Oedogonium

•      Higher plants- disc shape, oval or circular out line, rarely- lens shape, rounded, or club shaped.

•      Size Variable, in Higher plants-  4-10 μm  / 2-4μm  .

•      In spirogyra algae - 1mm .

            ULTRA STRUCTURE


Chloroplast

 

•      In the chloroplast , 3 parts present-

1. Envelope

2. Matrix/ Stroma

3. Thylakoids

•      Pyrenoid and Stigma may present.

Chloroplast Envelope

Chloroplast
Chloroplast

•      It contain Double smooth membrane envelope.

•      Membrane is 90- 100 A0 thick.

•      An Inter membrane space present – 100-200 Ao

•      Outer membrane attached to the ER.

•      Outer membrane is more permeable.

•      Inner membrane connected to Thylakoid.

•      Inner membrane is with more carrier proteins.


Matrix/Stroma

•      The ground substance is called as matrix or stroma.

•      The Semifluid colloid stroma contain- Soluble protein 50%, cp DNA, RNA, ribosomes, enzymes, minerals, ions etc.

•      Fully functional circular double stranded DNA present.

•      Ribosome- 70s type.

•      Photosynthetic pigments are abundant.

•      May contain Lipid droplet (Plasto globuli) -100-500nm.

•      Some time starch grain, pyrenoid present.

Thylakoid

•      Internal membrane - runs throughout the matrix.

•      Thylakoids are Sac like flattened tubes or channels.

•      These are the structural elements which take part in photo synthesis, called photo synthetic thylakoid.

•      In Higher plants – thylakoid stacked together to form Grana and 40- 60 grana present in a single chloroplast.

•      1 Granum has 2-100 grana thylakoid.

•      Agranal structure- algae and bundle sheath cell.

•      Thylakoid is of two type - Grana Thylakoid and stroma thylakoid (Integral thylakoid).

•      Thylakoid membrane contain- pigments, coupling factors (proteins for ATP synthesis).

•      Pigments - Chlorophyll a, Chl-b, Carotene and xanthophyll.

•      All these pigments form a group or Photo system or quantosome  (I And II)

•      PS I –present at stroma thylakoid

•      PS II- present at appressed part of grana

 

 

Semi Autonomous Organelle:

•      Contain Own DNA.

•      DNA perform Replication and transcription.

•      It has its Own RNA.

•      It can perform own protein production.

•      It has its Own enzyme system.

•      New chloroplast arise from the pre-existing one or from proplastid.

•      But it can’t survive with out cell.

 

Function

•      Perform Photosynthesis.

•      Radiation energy transduction or storage.

•      Carbon dioxide Recycle or Consumption.

•      Production of reducing power- reduction of nitrate and form A.A.

•      It is involved in Oxygen production.

•      Storage of starch.

•      Synthesis of F.A.

•      Storage of Lipid – in the form of plastoglobuli.

•      Help in Photo sensitivity- in algae.

•      Formation of Chromoplasts- in flower and fruits.

 

 

 

 

 

Difference between Mitochondria and Chloroplast:

 

Difference-Mitochondria-chloroplast
Difference-Mitochondria-chloroplast







That's all about Mitochondria and chloroplast. Feel free to ask doubts in comment section.. uksir.


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