Discuss the role the brush border of the intestinal cells plays in the final digestive and absorptive steps of
carbohydrates, proteins and fats. What will be an ideal response?
ANSWER: Polysaccharides are broken down into simple sugars. Proteins are broken down into amino
acids. The final steps of this process occur at the brush border. The end-products of both
carbohydrate and protein digestion are then absorbed by active transport into brush border
cells. The end-products then move out of the cell and into the blood. Triglycerides are
surrounded by bile salts into an emulsified droplet. The small droplets are digested by lipase
enzymes. The end-products (fatty acids and glycerol) are surrounded by bile salts forming
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Complexity in cell communication from molecular cross talk can be due to (select all correct choices):
A. inhibition of one signaling pathway by a component of another signaling pathway. B. an intersection of two signaling pathways that allow two signals to enhance the cellular response. C. signaling molecules interacting and inhibiting or enhancing their activation potential. D. None of these choices is correct.
About 12,000 years ago, a mass extinction event occurred and 75% of the world's large mammal species were eliminated. While a small number of cheetahs managed to survive and restore the world's population of cheetahs, this event caused an extreme reduction of the cheetah's genetic diversity. Based on the principles of natural selection, which of the following is a consequence of their reduced genetic diversity?
A. Cheetahs are unable to effectively compete with each other for resources. B. Cheetahs have very little heritable variation, which will make it difficult for them to adapt as the environment changes. C. Cheetahs have never fully adapted to the current environment. D. Cheetahs within the same population do not vary in their reproductive success.
Why are molecular characteristics the choice for modern phylogenetic analysis over morphological traits?
A. I. They generate a shorter tree than the morphological traits B. II. They generate a longer tree than the morphological traits C. III. There are more molecular characters to draw relationships from D. IV.Molecular characters are more objective. E. V.Morphological trees are obsolete F. All of the above G. I, III, IV, V H. III, IV, & V J. III & IV
Each species has a typical survivorship curve. Identify the labeled curves and briefly describe the typical survival rates and when death occurs. Give examples of organisms that have this type of survivorship curve.
What will be an ideal response?