Transpiration is least in which of the following conditions?
High atmospheric humidity means large amount of water vapour in the surrounding atmosphere. There would be no more space in the atmosphere to hold more water vapours. So rate of transpiration decreases.
The movement of leaves of Mimosa pudica are due to
Seismonasty is the nastic response of a plant to touch or vibration. It is also known as thigmonasty.
Gibberelins promote seed germination. They stimulate the production of hydrolytic enzymes such as amylases, lipases, proteases. These enzyme solubilise the reserve food material and helps in germination.
The circadian rhythms of plants and animals are maintained by which of the following?
Cryptochromes are flavoproteins that are sensitive to blue light. They are present in both plants and animals and are involved in their circadian rhythms.
In C4 plants, Calvin cycle takes place in
In C4 plants special anatomy is present called kranz anatomy and Calvin cycle occurs in stroma of bundle sheath chloroplasts.
Which of the following is a driving force for movement of water from soil to root during absorption of water by a plant?
The osmotic potential is the amount of solute or minerals/ions, soil has more osmotic potential than roots, so ions move into the roots. To balance the solute potential, water also moves into the roots, which leads to absorption of water from soil by roots.
Which of the following statement is true with regard to guard cells?
Guard cells are not joined to each other by plasmodesmata.
Cytochrome b structure has which centre?
Cytochromes are heme-containing proteins. They have Fe centres.
Match the following:
Ascent of sap is the mechanism by which water travels in a plant against gravity. Assimilation means the process of absorption and digestion of nutrients by an organism. Somatic embryos are also known as artificial seeds. Asphyxiants destroy pests by causing them respiratory distress.
The conversion of ACC to ethylene during ethylene biosynthesis is catalysed by which of the following?
ACC oxidase catalyses the last step in ethylene biosynthesis i.e. the conversion of ACC to ethylene in the cytosol.
During photorespiration in plants, carbon dioxide is produced when glycine is converted to serine in
Photorespiration in plants involves three organelles - chloroplast, peroxisome and mitochondria. Here, glycolate converts into glycine in peroxisomes and this glycine is converted into serine giving off CO2 in the process. This CO2 is produced in mitochondria.
The process of ammonification is
The process of converting organic nitrogen to ammonia is ammonification. It occurs during the process of decomposition of plants and animals by fungi and bacteria.
Photo respiration occurs in which of these sites?
Photorespiration is the process in which the enzyme Rubisco binds to O2 instead of CO2. This reaction has 3 organelles where intermediate steps occur. These are chloroplast, mitochondria and peroxisome.
Which of the following is incorrect with regard to active transport?
Active transport takes place against concentration gradient. It is an endergonic process.
Which of the following is not true for CAM plants?
In CAM plants, since CO2 is concentrated around Rubisco, photorespiration is minimized and efficiency is maximized. CO2 collected during night is converted to malate and stored in vacuoles until it is used up in photosynthesis.
Which of the following is correct statement?
Sufur is a component of cysteine and methionine.
Which of the following reactions are catalysed by enzyme nitrogenase?
Nitrogenase undertakes catalysis of all these reactions.
The number of water molecules required to generate one O2 in the light reaction of photosynthesis is _______[Answer in integer]
2H2O → 2H2 + O2
∴ 2 molecules of water given are one molecule of oxygen and 2 molecules of hydrogen.
The number of ATP molecules required for fixing one molecule of CO2 in C4 plants is __________ [Answer in integer]
The C4 cycle which involves PEP requires 2 ATP. The C3 cycle which is common in all plants requires 3 ATP.
Therefore, total ATP required to fix one molecule of CO2 in C4 plants is 5ATPs.
The number of electrons released during photolysis when 1 molecule of oxygen is evolved are__________[Answer in integer]
The reaction is as follows:
Thus 4 protons and 4 electrons are released to evolve 1 molecule of oxygen.
Number of turns of Calvin cycle required to make one molecule of glucose is __________ [Answer in integer]
Glucose is a 6C molecule 1 C is fixed in each turn of the Calvin cycle so 6 turns are needed to make 1 glucose molecule.