The Structure of Chloroplasts in Plants

Written by diane evans
  • Share
  • Tweet
  • Share
  • Pin
  • Email
  • Introduction

    The Structure of Chloroplasts in Plants

    Chloroplasts are organelles found only in plant cells. They contain the green pigment, chlorophyll, a photoreceptor that enables plants to capture light energy from the sun for photosynthesis. The structure of the chlorophyll molecule is very similar to the haemoglobin molecule found in animal blood. The difference is that while the heme molecule contains an iron atom, chlorophyll contains a magnesium atom in its centre.

    Chlorophyll is the green pigment in leaves. ( Images)

  • 1 / 4


    Plastids are organelles that function in the manufacture and storage of compounds used by the cell. Biologists classify them according to the pigment they contain. Chloroplasts containing chlorophyll are green, but chromoplasts contain different carotenoids in yellow, red and orange. Chloroplasts are the site for photosynthesis in the plant cell. Here sunlight is absorbed and converted to energy to produce sugars and starches.

    Photosynthesis takes place in the chloroplast. (Jupiterimages/ Images)

  • 2 / 4


    Under the electron microscope, chloroplasts appear as flat discs encased by an envelope consisting of an inner and outer membrane. The material within the chloroplastid is the stroma which corresponds to the intracellular fluid inside the cells. Its composition is mainly water, dissolved ions, proteins such as ribosomes, enzymes and other small molecules. Chemical reactions producing starches and sugars take place in the thylakoids, the sub-organelles stacked in the stroma.

    Chromoplasts contain red, yellow and orange carotenoids. (Jupiterimages/ Images)

  • 3 / 4


    Chloroplasts, the food producers of the cell, use the photosynthesis process in the thylakoids to make sugars and starches with oxygen as a by-product. The thylakoids are interconnected, flat membrane sacs that the cell uses for the reaction. Photosynthesis is a reaction powered by sunlight energy in which chlorophyll combines carbon dioxide and water to produce glucose and oxygen.

    Oxygen is a by-product of photosynthesis. (Jupiterimages/ Images)

  • 4 / 4

    Chloroplasts and Mitochondria

    While chloroplasts use photosynthesis to convert sunlight energy into glucose, mitochondria work in opposition as they break down the sugars and nutrients for the cell's use. Mitochondria are very similar in structure to chloroplasts in that these organelles are surrounded by two layers of membranes. Mitochondria produce power in the cells by converting energy into forms that the cell can use. Researchers believe that mitochondria and chloroplasts evolved together from prokaryotes that were once independent organisms.

    Chloroplasts are photoreceptors for sunlight. (Hemera Technologies/ Images)

Don't Miss

  • All types
  • Articles
  • Slideshows
  • Videos
  • Most relevant
  • Most popular
  • Most recent

No articles available

No slideshows available

No videos available

By using the site, you consent to the use of cookies. For more information, please see our Cookie policy.