Use the Following Information When Answering the Question Below

question 33

Multiple Choice

Use the following information when answering the question below.
The crucian carp Carassius carassius) is a Northern European freshwater fish often inhabiting ponds that become hypoxic hav reduced oxygen levels) and even anoxic have no oxygen) when the surface freezes during the winter. Surprisingly, when oxygen levels are normal, these fish lack the lamellae that provide a large surface area for gas exchange between water and blood: their gills are smooth. Yet when the level of oxygen in the water falls, the gill morphology undergoes a change:
packing cells stop dividing and programmed cell death is induced, exposing gill lamellae that were buried in other tissue. With lamellae exposed, the gills have increased surface area for gas exchange. These changes in gill lamellar profile are reversible: investigators observed that the gills return to their normal structure within 7 days after returning the fish to
well- oxygenated water. Jørund Sollid, Paula De Angelis, Kristian Gundersen, and Göran E. Nilsson. 2003. Hypoxia induces adaptive and reversible gross morphological changes in crucian carp gills. Journal of Experimental Biology 206:3667- 73.)
-Gills serve multiple functions in fish in addition to gas exchange. Given the large surface area of gills with lamellae, what is the most likely explanation for why crucian carp cover protruding lamellae in their gills when levels of oxygen are normal?

• A) to prevent loss of heat to the surrounding water
• B) to prevent protein loss to the surrounding water
• C) to prevent loss of ions to the surrounding water
• D) to prevent loss of oxygen to the surrounding water

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Definitions:

Genetic Polymorphism

The simultaneous occurrence of two or more discrete phenotypes within a population. In the simplest case, each phenotype results from a different allele or combination of alleles of a single gene. In more complex cases, the phenotypes result from complex interactions between many different genes and the environment.

Phenotypes

The set of visible or measurable traits of an organism that arise from the interaction of its genotype with the environment.

Population

A population consisting of members of the same species who live and reproduce within a specific region.

Protein Structure

The three-dimensional arrangement of atoms within a protein molecule, which determines the protein's functions based on its shape, including primary, secondary, tertiary, and quaternary structures.