#Question id: 718
#Unit 1. Molecules and their Interaction Relevant to Biology
Poly- L -leucine in an organic solvent such as dioxane is a helical, whereas poly- L isoleucine is not. Why do these amino acids with the same number and kinds of atoms have different helix-forming tendencies?
#Question id: 5362
#Unit 8. Inheritance Biology
From the following select the possible mode of inheritance and the probability that the daughter in generation III will show the trait.
#Question id: 10656
#Unit 10. Ecological Principles
Which of the following is an incorrect statement about the regulation of populations?
A) The logistic equation reflects the effect of density independent factors, which can ultimately stabilize populations around the carrying capacity.
B) Density-independent factors have an increasingly greater effect as a population’s density increases.
C) High densities in a population may cause physiological changes that inhibit reproduction.
D) Because of the overlapping nature of population-regulating factors, it is often difficult to precisely determine their cause-and-effect relationships.
#Question id: 10920
#Unit 6. System Physiology – Plant
The pressure-flow model, first proposed by Ernst Münch, Phloem loading at the source and phloem unloading at the sink establish the pressure gradient.
a.) In source tissues, an accumulation of sugars in the sieve elements generates a lower or negative solute potential (ψs).
b.) source tissue, causes a steep drop in the water potential (ψ), due to water potential gradient, water enters the sieve elements and causes turgor pressure (ψp ) decrease.
c.) In sink tissues, phloem unloading leads to a lower sugar concentration in the sieve elements, generating a higher or less negative solute potential.
d.) As the water potential of the phloem rises above that of the xylem, water tends to leave the phloem in response to the water potential gradient, causing a decrease in turgor pressure in the sieve elements of the sink.
Which of the following statements of sink and source tissue is FALSE?
#Question id: 11500
#Unit 9. Diversity of Life Forms
The strongest evidence for the endosymbiotic origin of eukaryotic organelles is the similarity between extant prokaryotes and which of the following?