Question

A student sets up an experiment on photosynthesis as follows: He takes soda water in glass tumbler and adds chlorophyll extract into the contents and keeps the tumbler exposed to sunlight hoping that he has provided necessary ingredients for photosynthesis to proceed (viz., $C{O}_2,H_{2}O$, chlorophyll and light). What do you think will happen after a few hours of exposure of light?

• A. Photosynthesis will take place and glucose will be produced.
• B. Photosynthesis will take place and starch will be produced which will turn the mixture turbid.
• C. Photosynthesis will not take place because $C{O}_2$ dissolved in soda water escapes into the atmosphere.
• D. Photosynthesis will not take place because intact chloroplasts are needed for the process.

Answer 1

Answer: (D)

$C_4$ pathway was first reported in members of family Gramineae (grasses) like sugarcane, maize, sorghum, etc. These $C_4$ plants have a characteristic leaf anatomy called $Kranz$ anatomy. So in chloroplasts of mesophyll cells -PEPCo (PEP carboylase) is the key enzyme used to fix $C{O}_2$ in $C_4$ plants Oxaloacetic acid is a 4-C compound and is the first stable product so this pathway is known as $C_4$ cycle.In plants, during photosynthes is starch is formed as a food. In the given experiment ,all the conditions necessary for photosynthesis i.e. sunlight, chlorophyll, $C{O}_2$ and $H_{2}O$ are present. So, photosynthesis will occur and $C{O}_2$ produced from soda water will make the mixture turbid.