Answer: They protect mRNA from degradation and aid ribosome binding.
- A They encode the start and stop codons recognized during translation
- B They protect mRNA from degradation and aid ribosome binding
- C They are excised together with introns during the spliceosome reaction
- D They serve solely as the signal required for nuclear pore export
Correct answer: B. They protect mRNA from degradation and aid ribosome binding
Explanation: The 5' 7-methylguanosine cap protects mRNA from nuclease degradation and helps ribosome binding. The 3' poly-A tail also protects mRNA and aids in nuclear export and translation.
As substrate concentration rises, reaction rate increases steeply at first, then plateaus at Vmax once every enzyme molecule is working at full capacity; Km is the substrate concentration giving half-maximal rate, and a LOWER Km means the enzyme reaches that rate with less substrate (higher affinity).
Concept context
Carbohydrates, proteins, lipids, nucleic acids, and enzyme kinetics. Essential foundation for understanding metabolism.