#Question id: 31293
#Unit 5. Developmental Biology
#Question id: 622
#Unit 1. Molecules and their Interaction Relevant to Biology
An enzyme-catalyzed reaction was carried out with the substrate concentration initially a thousand times greater than the Km for that substrate. After 9 minutes, 1% of the substrate had been converted to product, and the amount of product formed in the reaction mixture was 12 micromol. If, in a separate experiment, one-third as much enzyme and twice as much substrate had been combined, how long would it take for the same amount (12 micromol) of product to be formed?
#Question id: 15770
#Unit 5. Developmental Biology
#Question id: 804
#Unit 1. Molecules and their Interaction Relevant to Biology
With respect to microRNAs, which, if any, of the following statements, is false?
a) A microRNA normally works by binding to perfectly complementary sequences within an RNA transcript, usually an mRNA.
b) Like the great majority of mRNAs an miRNA is usually produced as a larger precursor RNA that is capped and has a 3’ poly(A) tail.
c) The precursor miRNA undergoes different types of post-transcriptional cleavage by endoribonucleases that are specific for double-stranded target sequences.
d) A nuclear endoribonuclease called dicer cleaves the miRNA precursor so that it forms a stem-loop RNA.
#Question id: 2803
#Unit 2. Cellular Organization
A human cell contains 3X109 bp per set of chromosomes.