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Biology 2e

Critical Thinking Questions

Biology 2eCritical Thinking Questions


Why are biological macromolecules considered organic?


What role do electrons play in dehydration synthesis and hydrolysis?


Amino acids have the generic structure seen below, where R represents different carbon-based side chains.

The generic structure of amino acids is shown. A nitrogen atom is single bonded to two hydrogen atoms and one carbon atoms. The carbon atom is single bonded to one hydrogen atom, one R atom, and one carbon atom. R represents different carbon-based side chains. The carbon atom is double bonded to one oxygen atom and single bonded to a hydroxide atom.

Describe how the structure of amino acids allows them to be linked into long peptide chains to form proteins.


Describe the similarities and differences between glycogen and starch.


Why is it impossible for humans to digest food that contains cellulose?


Draw the ketose and aldose forms of a monosaccharide with the chemical formula C3H6O3. How is the structure of the monosaccharide changed from one form to the other in the human body?


Explain at least three functions that lipids serve in plants and/or animals.


Why have trans fats been banned from some restaurants? How are they created?


Why are fatty acids better than glycogen for storing large amounts of chemical energy?


Part of cortisol’s role in the body involves passing through the plasma membrane to initiate signaling inside a cell. Describe how the structures of cortisol and the plasma membrane allow this to occur.


Explain what happens if even one amino acid is substituted for another in a polypeptide chain. Provide a specific example.


Describe the differences in the four protein structures.


Aquaporins are proteins embedded in the plasma membrane that allow water molecules to move between the extracellular matrix and the intracellular space. Based on its function and location, describe the key features of the protein’s shape and the chemical characteristics of its amino acids.


What are the structural differences between RNA and DNA?


What are the four types of RNA and how do they function?

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