Question

Label the diagram and write down the detail of the concept in your word.

Answer 1

Chloroplast plays a significant role in the synthesis of starch in plants.

Structure of chloroplast:

1. In plants, the chloroplast is found mainly in mesophyll of leaf.
2. A chloroplast is lens-shaped but it can also be oval, spherical, discoid, or ribbon-like.
3. A cell may contain a single large chloroplast as in Chlamydomonas or there can be 20 to 40 chloroplasts per cell as seen in mesophyll cells.
4. Chloroplasts contain a green pigment called chlorophyll along with other enzymes that help in the production of sugar by photosynthesis.
5. Inner membrane of double membraned chloroplast is comparatively less permeable.
6. Inside the cavity of inner membrane, there is another set of membranous sacs called thylakoids.
7. Thylakoids are arranged in the form of stacks called grana (singular: granum).
8. The grana are connected to each other by means of membranous tubules called stroma lamellae.
9. Space outside thylakoids is filled with stroma.
10. The stroma and space inside thylakoids contain various enzymes essential for photosynthesis.
11. Stroma of chloroplast contains DNA and ribosomes (70S).