Question

rnai is a technique that silences genes by targeting them and degrading their mrna. how can this technique be used in scientific laboratories?
a) rnai allows scientists to turn off one gene specifically to study its effect.
b) rnai is observed in nature, but it cant be used in laboratories.
c) rnai is a powerful tool for degrading mrna, but because it doesnt degrade other types of rna, its use is limited.
d) rnai has been used in laboratories to make bacteria more susceptible to antibiotics, but has limited application in eukaryotic cells.
question 10 (5 points)
listen
how might a gene mutation be silent, with no observable effect on a cell or an organism?
a) many proteins are superfluous to the function of a cell. a gene mutation in a gene that encodes an unnecessary protein would have no observable effect on the cell or the organism.
b) several codons are stop codons. a gene mutation that inserts a stop codon when only a few amino acids remain in the peptide sequence would have no observable effect on the cell or the organism.

Explanation:

First Question (about RNAi in laboratories)

• Option B is wrong because RNAi can be used in labs (e.g., to study gene function).
• Option C is incorrect as RNAi's main role is mRNA degradation for gene silencing, and its use isn't limited just by not degrading other RNAs (it's widely used for gene function studies).
• Option D is wrong since RNAi is used in eukaryotic cells too (e.g., in research on human, plant, or animal cells to study gene roles).
• Option A is correct: RNAi's specificity to target and silence a single gene makes it a key tool to study what that gene does by observing effects when it's turned off.

Second Question (about silent gene mutation)

(Note: The options provided seem incomplete, but based on the given ones and silent mutation knowledge: A silent mutation typically involves a change in DNA that doesn't change the amino acid sequence, often due to the genetic code's redundancy. However, among the given options:

• Option A's reasoning about "superfluous proteins" is flawed (cells don't have unnecessary proteins; most proteins have functions).
• Option B: Inserting a stop codon early would truncate the protein, likely causing an effect, not a silent mutation.

Assuming there might be a missing option with the correct silent mutation mechanism (like a codon change that codes for the same amino acid), but with the given options, if we have to choose, neither A nor B is correct in standard silent mutation terms. But if forced to pick from the given:

Answer:

A) RNAi allows scientists to turn off one gene specifically to study its effect.