In genetics, the '5' cap' is a modified guanine nucleotide added to the 5' end of eukaryotic mRNA. Its primary functions include: MCQ with Answer and Explanation
In genetics, the '5' cap' is a modified guanine nucleotide added to the 5' end of eukaryotic mRNA. Its primary functions include:
A. Adding the poly-A tail
B. Protecting the mRNA from degradation and facilitating ribosome binding for translation initiation
C. Splicing out introns
D. Terminating transcription
Answer: Option B
Solution (By JKSSB Mock Tests)
The 5' cap is a specially altered nucleotide (7-methylguanosine) attached via a 5'-5' triphosphate linkage to the 5' end of a eukaryotic mRNA molecule shortly after transcription begins. Its primary functions are to protect the nascent mRNA from degradation by 5' exonucleases, to facilitate the export of the mature mRNA from the nucleus to the cytoplasm, and, crucially, to be recognized by the eukaryotic initiation factor 4E (eIF4E), which is essential for recruiting the ribosome to the mRNA to initiate translation.
Explanation:
The Calvin cycle fixes CO₂ into glucose, which is the primary organic product of photosynthesis. Oxygen is a byproduct of water splitting.
Explanation:
Commensalism (+/0) involves one species benefiting and the other neither harmed nor helped. Example: barnacles on a whale, or cattle egrets eating insects stirred by cattle. Mutualism benefits both (+/+), parasitism benefits one at expense of other (+/-), predation (+/-) involves killing. The distinction is based on the net effect.
Explanation:
The correct taxonomic hierarchy in ascending order is: Species (lowest) → Genus → Family → Order → Class → Phylum (or Division in plants) → Kingdom (highest). Some classifications add Domain above Kingdom. This system groups organisms based on shared characteristics. Binomial nomenclature uses Genus and Species. Option A correctly places Family before Order.
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