Refer to the Following Paragraph and Figure 3

question 33

Multiple Choice

Refer to the following paragraph and Figure 3.1 to answer the following questions.

Figure 3.1
Since structure correlates so well with function,biochemists are constantly looking for new ways to probe the complex structure of proteins in order to understand what they do and how they do it.One of the most powerful techniques in existence today is X-ray crystallography.The main difficulty with this technique is getting the protein to crystallize.Once crystallized,the protein is bombarded with X-rays to create a pattern that can be analyzed mathematically to determine the three-dimensional structure of the protein.This analysis has been performed by Krzysztof Palczewski on the protein rhodopsin,which is a light-sensitive protein found in species ranging from ancient bacteria (archaea) to humans.The structure (schematically shown above,where each letter represents an amino acid) is characterized by a single polypeptide chain with several α-helical segments that loop back and forth across the cell membrane.Another notable feature is the disulfide bond (-S-S-) that can be seen at the bottom of the third transmembrane segment.[Figure adapted from K.Palczewski et al. ,Science 289 (2000) : 739.]
-Which term best describes the type of membrane protein in Figure 3.1?

• A)peripheral
• B)external
• C)internal
• D)integral

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Definitions:

Benzene

A basic and important aromatic hydrocarbon with a ring structure that consists of six carbon atoms with alternating double and single bonds.

Bromination

The chemical reaction in which a bromine atom or molecule is introduced into another molecule.

Major Organic Product

The primary outcome of a chemical reaction involving organic reactants; it is usually the most abundant product formed.

Major Organic Product

In organic chemistry, the predominant compound that forms as the result of a chemical transformation.