The mussel Mytilus edulis thrives in saline habitats, in both the highly salty seawater of tidal zones and the less salty estuaries. This results in two kinds of populations: one adapted to the higher salt concentrations of the tidal zone, and one adapted to the lower salt concentrations of the estuary. It has been found that the more salt-tolerant populations have high frequencies of an allele that produces an enzyme involved in maintaining osmotic equilibrium. Conversely, estuarine mussels having the same enzyme seem to be disfavoured and have a much higher death rate than mussels without the allele. Adult estuarine populations do have lower frequencies of this allele. Each spring, large numbers of larvae from  the salty habitats pour into the estuaries.

The invasion of the seawater larvae would be expected to facilitate change in the genetic structure of the estuarine population by a process called

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#Question id: 13195

#Unit 1. Molecules and their Interaction Relevant to Biology

Who contributes to the stability of DNA helix structure?

A. Hydrogen bonding between bases

B. Hydrogen bonding between water and bases

C. Scattering interactions between bases

D. Stacking interactions between bases

CORRECT combination is

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#Question id: 13194

#Unit 1. Molecules and their Interaction Relevant to Biology

If we have the sequence 5’-ATGTC-3’ on one chain, the opposite chain must have the complementary sequence 

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#Question id: 13193

#Unit 1. Molecules and their Interaction Relevant to Biology

Data, collected from DNAs of a great many different species, led Chargaff to the following conclusions:

A. The base composition of DNA generally varies from one species to another.

B. DNA specimens isolated from different tissues of the same species have the different base composition.

C. The base composition of DNA in a given species changes with an organism’s age, nutritional state, or changing environment.

D. In all cellular DNAs, the sum of the purine residues equals the sum of the pyrimidine residues.

Which of the above statements are INCORRECT regarding Chargaff’s rule?

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#Question id: 10476

#Unit 1. Molecules and their Interaction Relevant to Biology

Following statements are regarding to gangliosides.

A. They are ceramides with attached oligosaccharides that include at least one sialic acid residue.

B. They are ceramides with attached oligosaccharides that include at least one phasphatidic acid residue.

C. Sialic acid gives gangliosides the negative charge at pH 7 that distinguishes them from globosides.

D. Gangliosides are primarily components of cell-surface membranes and constitute a significant fraction (6%) of brain lipids.

Which of the following combination is correct?

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#Question id: 10475

#Unit 1. Molecules and their Interaction Relevant to Biology

During the formation of a blood plasma protein The aromatic ring of vitamin K undergoes:

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#Question id: 10474

#Unit 1. Molecules and their Interaction Relevant to Biology

Lipids differ from other large biological molecules in that they