The enzyme that breaks down starch into maltose in the mouth is:
A. Lipase
B. Pepsin
C. Rennin
D. Salivary amylase
Answer: Option D
Solution (By JKSSB Mock Tests)
Salivary amylase (ptyalin) initiates starch digestion in the mouth, hydrolyzing it into maltose and dextrins. Pepsin digests protein, lipase fats, rennin curdles milk. Amylase works optimally at neutral pH.
Explanation:
Decomposition involves several steps. Leaching is the process where water-soluble inorganic nutrients (like nitrates, phosphates) are washed out of the decomposing organic matter (detritus) and move deep into the soil profile, where they may become unavailable to plants. Fragmentation is the breakdown of detritus by detritivores (like earthworms).
Explanation:
The umbilical vein carries oxygen-rich and nutrient-rich blood from the placenta to the fetal circulation. The two umbilical arteries carry deoxygenated blood and waste from the fetus to the placenta. In the adult, veins typically carry deoxygenated blood, but umbilical vein is an exception.
Explanation:
Mitochondria and chloroplasts contain their own DNA and ribosomes (70S) and can replicate by binary fission, a feature supporting their endosymbiotic origin. Golgi apparatus, lysosomes, and rough ER cannot self-replicate; they are part of the endomembrane system and arise from pre-existing membranes. Mitochondria are thus semi-autonomous organelles.
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