Explain how dicer and miRISC are involved in the production and function of miRNAs
What will be an ideal response?
ANSWER: Pre-miRNA exists in a stem-loop structure after it is transcribed. The pre-miRNA is exported
to the cytoplasm where dicer removes the loop to produce a short double-stranded RNA
molecule. A protein complex binds to the double-stranded RNA, and an enzyme in the
complex degrades one of the RNA strands. The miRNA and the complex form the miRNAinduced
silencing complex (miRISC). miRNA in the miRISC binds to target mRNAs that
have complementary or nearly complementary base sequences in their 3¢ UTRs. If the
pairing is imperfect, translation of that mRNA is blocked. If the pairing is perfect, the mRNA
is destroyed.
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An organism may use glycolysis and the pentose phosphate pathway simultaneously.
Answer the following statement true (T) or false (F)
Alleles are alternate molecular forms of a gene
A. true B. false
Your dog has flu caused by an H3N8 strain. Assume that you breathe in this strain, after you have already come in contact with an H1N1 strain. Both viruses go into the cells of your upper respiratory tract. During the viral replication cycle inside of your epithelial cells, genetic information for hemagglutinin antigen and for neuraminidase antigen are recombined. Your cells end up producing a new variant---H3N1. Predict what might happen as a result of this set of events.
A. This is not a problem because the human immune system can respond quickly to any new antigens never seen before. B. Since this new virus has antigens from a dog strain, the new strain will not be able to infect human cells. C. This novel virus will spread through the human population without much resistance. D. Only people who have never had flu before will get sick from the new H3N1 variant.
Which impact is occurring due to global climate change? a. Sea level is decreasing due to greater rates of evaporation
b. Deciduous trees are putting out their leaves later in the spring. c. Warming of tropical waters that increase coral production. d. Spring blooming flowers are staying dormant longer. e. Increased intensity of hurricanes.