The Thin Envelope of Life That Surrounds the Earth's Surface

question 20

Multiple Choice

The thin envelope of life that surrounds the earth's surface is called the

• A)atmosphere.
• B)biosphere.
• C)lithosphere.
• D)hydrosphere.
• E)ecosystem.

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Definitions:

mRNA

Messenger RNA, a type of RNA that conveys genetic information from DNA to the ribosome, where it specifies the amino acid sequence of the protein products of gene expression.

Protein Structure

The specific three-dimensional arrangement of amino acids in a protein, determining its function and activity, includes primary, secondary, tertiary, and quaternary structures.

Exons

Segments of a DNA or RNA molecule containing information coding for a protein or peptide sequence.

Introns

Noncoding sections of an RNA transcript, or the DNA encoding it, that are removed before the RNA molecule is translated into a protein.