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 Multiple Choice QuestionsMultiple Choice Questions

1.

Photosynthetic bacteria do not contain

  • quantasome

  • PS- I and PS- II

  • PS-II

  • PS-I


A.

quantasome

Photosynthetic bacteria are of two types- Oxygenic and Anoxygenic. They do not have chloroplast, and photosynthesis takes place within the cell. In cyanobacteria, thylakoids lie naked in the cytoplasm and attached to them are minute structures called phycobilisomes which contain the pigments. Bacteria have only one photosystem i.e. type I reaction centre (PS I- 700) in green sulphur bacteria and type II (PS II- 680) in non sulphur bacteria.


2.

Which of the following statements is correct regarding short day plants (SDPs)?

  • They can flower in complete darkness if supplied with exogenous nutrients.

  • They are the same as long day plants.

  • They do not have a critical photoperiod

  • All of these.


A.

They can flower in complete darkness if supplied with exogenous nutrients.

Short Day Plants or SDPs are the plants that require a long period of darkness. These plants can flower in complete darkness if supplied with exogenous nutrients.


3.

Assertion : Stomata remain open during day.

Reason : Stomata help in exchange of gases.

  • If both Assertion and Reason are true and Reason is the correct explantion of Assertion

  • If both Assertion and Reason are true and Reason is not the correct explanation of Assertion

  • If Assertion is true but Reason is false

  • If Assertion is false but Reason is true.


B.

If both Assertion and Reason are true and Reason is not the correct explanation of Assertion

The opening and closing of stomata is a function of turgor changes in guard cells.

In light,  malic acid is produced in guard cells which dissociates into hydrogen and malate ions resulting in intake of  K+ ions through H+ - K+ ion exchange. There is increase in concentration of K+ and malate ions in guard cells, endosmosis of water into guard cells occurs resulting in increased turgor pressure which results in stomatal opening. These are concerned with gaseous exchange during photosynthesis and respiration and water loss through transpiration.


4.

Stomata opens

  • in day time - for gaseous exchange

  • in day time- no gaseous exchange

  • in night time only - for gaseous exchange

  • in night time only - no gaseous exchange


A.

in day time - for gaseous exchange

Stomata are meant for gaseous exchange but are also the main source of transpiration. In majority of plants stomata open in the presence of light, i.e. in daytime and close in darkness (night).


5.

Which of the following statements about phytochrome is true?

  • Pr absorbs yellow light and becomes Pfr

  • Pr absorbs red light and becomes Pfr

  • Pfr absorbs red light and becomes Pr

  • Pfr absorbs yellow light and becomes Pr


B.

Pr absorbs red light and becomes Pfr

Phytochrome is an amorphous photoreceptor chromoprotein. It exists in two interconvertible forms, i.e. Pr and Pfr.

Pr (inactive) Far redRed light Pfr (active)


6.

Who discovered photophosphorylation?

  • Arnon et. al.

  • Von Mayer

  • Calvin et. al.

  • Hill


A.

Arnon et. al.

Photophosphorylation refers to the use of light energy from photosynthesis to provide the energy to convert ADP to ATP.  It was discovered by D. Arnon and coworkers.


7.

Assertion : The collenchyma is a thick walled living tissue.

Reason : The collenchyma is thickened due to the deposition of pectin.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both the assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both the assertion and reason are false.


A.

If both assertion and reason are true and reason is the correct explanation of assertion.

Collenchyma is a specialized type of parenchyma which functions as a supporting tissue. The cell walls are irregularly thickened due to the deposition of cellulose and pectin. Hence, it is a living tissue.


8.

The photorespiratory carbon-oxidation cycle involves the interaction of

  • chloroplast

  • mitochondria

  • peroxisomes

  • all of these


D.

all of these

Photorespiration is a metabolic pathway that occurs in plants in the presence of light, in which ribulose bisphosphate carboxylase/oxygenase the (RuBisCO) enzyme involved in carbon dioxide fixation with ribulose bisphosphate, accepts oxygen, in place of carbon dioxide, resulting in the formation of a twocarbon compound, glycolate. Most of the fixed carbon represented by the glycolate can be salvaged by a series of reactions-the glycolate pathway involving the peroxisomes and mitochondria, and returned to the chloroplasts. However, some of the carbon is lost as carbon dioxide. Unlike respiration there is no production of ATP.


9.

Blackman's law is related to

  • respiration

  • transpiration

  • root pressure

  • photosynthesis


D.

photosynthesis

Blackman formulated the principle of limiting factors. He studied the effect of CO2 concentration, light intensity and temperature on the rate of photosynthesis.


10.

Photorespiration usually occurs in

  • one cell organelle

  • two cell organelles

  • three cell organelles

  • four cell organelles


C.

three cell organelles

In the process of photorespiration, uptake of oxygen and evolution of carbon- dioxide are light dependent. RuBP carboxylase acts as RuBP oxygenase. This process occurs in chloroplast and required the help of peroxisomes and mitochondria.