The Norway rat (Rattus Norvegicus), a widespread pest, was controlled for about a decade by the anticoagulant warfarin. This chemical substance, placed in food pellets, is absorbed by the intestinal tract and inhibits the clotting of blood. After a population decline for about 10 years, rat populations increased and stabilized. In one European population, as illustrated in the graph below, the percentage of rats resistant to warfarin has remained fairly stable over a number of years.

Resistance to warfarin is governed by a dominant autosomal gene, R. More than 15 percent of the resistant animals are heterozygous at this locus (Rr). The table below indicates the response to warfarin and relative reproductive fitness of individuals that are homozygous or heterozygous for the dominant gene (R). The RR individuals have a 20-fold increase in vitamin K requirement over individuals.

Fitness is a measure of the reproductive success of a particular genotype. The highest fitness is 1.00.

Which of the following is most likely correct concerning the gene for resistance to warfarin? 

#Question id: 7766

#Unit 5. Developmental Biology

The relationship between shortened telomeres and stem cell depletion has been seen in degenerative diseases such as mouse muscular dystrophy,

I) When____ is activated by damaged telomeres, DNA replication halts, and if the repair doesn’t work, apoptosis is initiated. If the cell is a stem cell or some other rapidly replicating cell, this will reduce the numbers of cells produced, and the lack of stem cells will produce an “aged” phenotype.

 II) When ____ is activated by damaged telomeres, DNA replication halts, repair do its work, apoptosis is inhibited. If the cell is a stem cell or some other rapidly replicating cell, this will increase the numbers of cells produced, and then these cells will produce an “aged” phenotype.

 Choose correct gene name with right statement

#Question id: 7767

#Unit 5. Developmental Biology

How can evolution select for phenotypes that postpone reproduction or sexual maturity?” There is often a trade-off between reproduction and maintenance, and in many species reproduction and senescence are closely linked. Recent studies of mice, Caenorhabditis elegans, and Drosophila suggest that there is a conserved genetic pathway that regulates aging and that it can indeed be selected for. This pathway involves the response to insulin and insulin-like growth factors, Name of these transcription factors are

#Question id: 7768

#Unit 5. Developmental Biology

The insulin signaling pathway inhibits the synthesis of the Foxo transcription factor proteins that would otherwise increase cellular longevity. Downregulation of the insulin signaling pathway has several other functions, choose right one

#Question id: 7305

#Unit 5. Developmental Biology

In plants, a growing mass of unorganized and undifferentiated cells that cover a wound; these cells can be induced to form a plant meristem and develop into shoots and/or roots called as

#Question id: 5647

#Unit 5. Developmental Biology

Use the following information to answer the question. In order to test how sea urchin sperm bind to eggs, scientists isolated the egg receptor protein

that binds to the sperm acrosomal protein called bindin. Plastic beads were coated with egg receptor for bindin (ERB1) from eggs of the sea urchin Strongylocentrotus purpuratus, and then the beads mixed with sperm from S. purpuratus or from the related species, S. franciscanus. The researchers counted how many sperm were bound to each bead. The results are shown in the graph below. Treatments:

A: S. purpuratus sperm mixed with S. purpuratus ERB1 beads

B: S. purpuratus sperm mixed with beads containing no ERB1 protein

C: S. franciscanus sperm mixed with S. purpuratus ERB1 beads

D: S. franciscanus sperm mixed with beads containing no ERB1 protein

Based on the data in the graph, which of the following conclusions is supported?

#Question id: 7751

#Unit 5. Developmental Biology