1
Question
Read the following statements (I - III) and select the correct option stating true (T) or false (F).
I. Arachaebacteria show biochemical adaptations to grow in hot springs.
II. People inhabiting places at higher altitudes have lesser availability of oxygen compared to the ones living in the plains.
III. Sunken stomata are mainly seen in aquatic plants.
Read the following statements (I - III) and select the correct option stating true (T) or false (F).
I. Arachaebacteria show biochemical adaptations to grow in hot springs.
II. People inhabiting places at higher altitudes have lesser availability of oxygen compared to the ones living in the plains.
III. Sunken stomata are mainly seen in aquatic plants.
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Solution
The correct option is A I - T, II - T, III - F
Adaptation is any attribute of the organism (morphological, physiological, behavioural) that enable them to survive and reproduce in its habitats. A habitat is the natural environment of the organism.
Archaebacteria are a group of unicellular, primitive, prokaryotic (devoid of a well-defined nucleus) organisms which are known as extremophiles due to their affinity to live in habitats with extreme conditions of temperature, pH or salinity.
The archaebacteria which live in hot springs or hydrothermal vents are termed as thermophiles. But in order to survive in high temperatures, these organisms have certain biochemical adaptations such as :
- The presence of more salts like potassium and magnesium, which protect double-stranded DNA from phosphodiester bond (in the backbone) degradation.
- Proteins with more disulfide bonds.
- Heat resistant enzymes (Taq polymerase from Thermus aquaticus) that do not get destroyed at high temperatures.
These characteristics enable the thermophiles to carry out basic life processes even at high temperatures. Thus statement I is true.
As we move to higher altitudes, the density of gases in air decreases gradually. Due to this the availability of oxygen at higher altitudes is less. Thus, people inhabiting places at higher altitudes have lesser availability of oxygen compared to the ones living in the plains. Hence statement II is true.
Desert plants are called xerophytic plants (Opuntia) as they are adapted to live in hot and dry climates. Maximum amount of transpiration (loss of water in the form of water vapour) in a plant body occurs through tiny pores on the leaves known as stomata. Thus, some xerophytic plants have sunken stomata buried in pits to prevent the loss of water via transpiration.
Figure : Sunken stomata
Floating aquatic plants (lotus) have stomata that remain open permanently to allow transpiration. Submerged aquatic plants (Hydrilla) do not contain stomata. Thus, statement III is false.
Adaptation is any attribute of the organism (morphological, physiological, behavioural) that enable them to survive and reproduce in its habitats. A habitat is the natural environment of the organism.
Archaebacteria are a group of unicellular, primitive, prokaryotic (devoid of a well-defined nucleus) organisms which are known as extremophiles due to their affinity to live in habitats with extreme conditions of temperature, pH or salinity.
The archaebacteria which live in hot springs or hydrothermal vents are termed as thermophiles. But in order to survive in high temperatures, these organisms have certain biochemical adaptations such as :
- The presence of more salts like potassium and magnesium, which protect double-stranded DNA from phosphodiester bond (in the backbone) degradation.
- Proteins with more disulfide bonds.
- Heat resistant enzymes (Taq polymerase from Thermus aquaticus) that do not get destroyed at high temperatures.
As we move to higher altitudes, the density of gases in air decreases gradually. Due to this the availability of oxygen at higher altitudes is less. Thus, people inhabiting places at higher altitudes have lesser availability of oxygen compared to the ones living in the plains. Hence statement II is true.
Desert plants are called xerophytic plants (Opuntia) as they are adapted to live in hot and dry climates. Maximum amount of transpiration (loss of water in the form of water vapour) in a plant body occurs through tiny pores on the leaves known as stomata. Thus, some xerophytic plants have sunken stomata buried in pits to prevent the loss of water via transpiration.
Figure : Sunken stomataFloating aquatic plants (lotus) have stomata that remain open permanently to allow transpiration. Submerged aquatic plants (Hydrilla) do not contain stomata. Thus, statement III is false.
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