Identify the correct statements:
A. Detrivores perform fragmentation.
B. The humus is further degraded by some microbes during mineralization.
C. Water soluble inorganic nutrients go down into the soil and get precipitated by a process called leaching.
D. The detritus food chain begins with living organisms.
E. Earthworms break down detritus into smaller particles by a process called catabolism.
Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R:
Assertion A: In gymnosperms the pollen grains are released from the microsporangium and carried by air currents.
Reason R: Air currents carry the pollen grains to the mouth of the archegonia where the male gametes are discharged and pollen tube is not formed.
In the light of the above statements, choose the correct answer from the options given below:
Given below are two statements: One is labelled as Assertion A and the other islabeled as Reason R: Assertion A: A flower is defined as modified shoot wherein the shoot apical meristem changes to floral meristem. Reason R: Internode of the shoot gets condensed to produce different floral appendages laterally at successive nodes instead of leaves.
In the light of the above statements, choose the correct answer from the options given below:
Explanation:
Assertion A: A flower is defined as a modified shoot where the shoot apical meristem changes to a floral meristem. This is the NCERT view: the floral meristem is formed from the shoot apical meristem and gives rise to floral organs. Reason R: Internode of the shoot condenses to produce floral appendages laterally at successive nodes instead of leaves. According to the statement, R provides a mechanism that corresponds to how floral structures arise from the meristematic region, aligning with the idea that floral parts are modified shoot structures. Hence, both statements are true and R explains A.
? Did You Know?
NCERT describes flowers as determinate shoot systems arising from a floral meristem, which differentiates into sepals, petals, stamens, and carpels.
? NCERT Memory Line:
Flower = modified shoot; floral meristem forms from shoot apical meristem to develop floral organs.
Identify the correct statements:
A. Lenticels are the lens-shaped openings permitting the exchange of gases.
B. Bark formed early in the season is called hard bark.
C. Bark is a technical term that refers to all tissues exterior to vascular cambium.
D.Bark refers to periderm and secondary phloem.
E. Phellogen is single-layered in thickness. Choose the correct answer from the options given below:
Melonate inhibits the growth of pathogenic bacteria by inhibiting the activity of:
Explanation:
Melonate inhibits the activity of succinic dehydrogenase, a key enzyme in the TCA cycle and electron transport chain of many bacteria. Blocking this enzyme disrupts aerobic respiration and energy production, thereby hindering bacterial growth. Among the options, succinic dehydrogenase (option 2) is the correct target. Dinitrogenase (nitrogenase) is involved in nitrogen fixation, amylase breaks down starch, and lipase breaks down fats; these are not the primary targets of melonate in NCERT-based bacterial physiology.
🧠 Did You Know?
Succinic dehydrogenase also functions as complex II of the mitochondrial/ bacterial electron transport chain, linking citric acid cycle to energy production.
💡 NCERT Memory Line:
Enzymes of respiration like succinic dehydrogenase are essential for energy release in bacteria and play a role in inhibiting growth when blocked.
