Video Transcript
The synthesis of chlorophyll in a
plant is regulated by specific genes. Which of the following best defines
the term gene? (A) A section of mRNA that can be
translated into a section of DNA. (B) A protein that is expressed in
the physical characteristics of an organism. (C) A section of DNA that codes for
the production of a protein or another functional unit. (D) All the genetic material that
is contained within an organism.
The question asks about the
definition of the term “gene,” using the production of chlorophyl as an example. DNA is the genetic material found
within chromosomes of eukaryotes, including plants. The information found in DNA is
copied into mRNA during a process called transcription. This mRNA can then be translated to
produce a protein. We can eliminate answer (A) because
we know that mRNA is translated to make a protein, not DNA.
The DNA of all the chromosomes in
plants can be billions of base pairs long. Some of this DNA makes up genes
that gives the instructions for making proteins or other functional units. However, most of the DNA is not
made up of genes and may have no known function or might be involved in regulatory
roles. Therefore, answer (D) is
incorrect.
As we have seen, a gene is a
section of DNA that may transcribe to make mRNA which can then be translated to make
protein. Therefore, answer (B) is incorrect
because a gene is a section of DNA and not a protein.
The proteins produced by genes can
then go on to regulate the synthesis of chlorophyll. The correct answer is (C): a
section of DNA that codes for the production of a protein or another functional
unit.
