Following statements are regarding to cell-cell and cell–extracellular matrix junctions and their adhesion molecules.

A. Adherens junctions and desmosomes are integrin-containing anchoring junctions that bind the membranes of adjacent cells, giving strength and rigidity to the entire tissue.

B. Hemidesmosomes are cadherin-containing anchoring junctions that attach cells to elements of the underlying extracellular matrix.

C. Integrins are a large family of αβ heterodimeric cell-surface proteins that mediate both cell-cell and cell-matrix adhesions and inside-out and outside-in signaling in numerous tissues.

D. Tight junctions block the diffusion of proteins and some lipids in the plane of the plasma membrane, contributing to the polarity of epithelial cells. They also limit and regulate the extracellular (paracellular) flow of water and solutes from one side of the epithelium to the other.

Which of the following statements are incorrect?

#Question id: 24570

#Unit 10. Ecological Principles

#Question id: 24569

#Unit 10. Ecological Principles

#Question id: 13143

#Unit 10. Ecological Principles

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.

#Question id: 13142

#Unit 10. Ecological Principles

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.

#Question id: 13141

#Unit 10. Ecological Principles

Five similar populations of a herbaceous annual plant are monitored for three years; then, the numbers of individuals in populations I-IV are increased by an experimenter. Subsequent changes in the sizes of all the populations are shown in the graph below.

If size distributions of individuals do not vary among these populations, which of the following relationships best illustrates the occurrence of population regulation?

#Question id: 13140

#Unit 10. Ecological Principles