Chapter 13: Photosynthesis in Higher Plants

The following measures were used: carbon dioxide, a radioactive isotope of carbon, was labelled C14 and was supplied to the plants for this experiment. The path C14 was then monitored and analysed. After the experiment on live plant got over, the plant was killed and the labelled compound was extracted from the dead plant and based on the observation in both live and dead Calvin and his colleagues found the pathway.

Glucose is a 6-carbon compound, so six carbon dioxide molecules are required to produce a single glucose molecule. Hence, six turns of the Calvin Cycle are required to generate one mole of glucose.

C4-plants, such as maize, sugar cane etc. are found in Kranz anatomy. These plants are also suitable for a limited nitrogen and carbon dioxide supply.

Cyanobacteria are unicellular prokaryotic organisms. They have photosynthetic pigments like chlorophyll ac, phycocyanin and phycoerythrin. These enable them to produce food by themselves. Green plants are multicellular organisms capable of making food by using carbon dioxide, water and light energy. Therefore the bacteria and green plants make food for living organisms on earth.

Tomatoes, carrots and chillies are red due to the presence of carotene pigment. It is an accessory photosynthetic pigment.

Extra genomic DNA is present in the chloroplast and mitochondria. This enhances the replication of these organelles. Thus believed that chloroplast and mitochondria as semi-autonomous.

(a) Monocot plants show bundle sheath cells and mesophyll cells.

(b) Oxaloacetic acid

(c) PEP carboxylase or PEP case.

(a) Photorespiration

(b) It is not essential for survival.

(c) Hydrogen peroxide

(d) It occurs in chloroplast, mitochondria and peroxisome.

a. Euphorbia is a CAM plant and maize is a C4 plant. Both can survive in tropical areas.

b. Maize due to the C4 plant

c. Leaves of maize plant show Kranz anatomy which is absent in Euphorbia plant.