GENETICS AND CELLULAR FUNCTION
Chapter 4 illuminates the processes collectively called the Central Dogma of Genetics. The Central Dogma
is the generally accepted sequence of operations that begin with the inheritance of a gene, its transcription
into RNA, and subsequent protein synthesis. Saladin also discusses Mendelian genetics at this time so that
there is a clear linkage between the cellular and the organismic events. Among the more important items
included under Mendalian genetics are dominance, population genetics, and sex-linked genes. Included in
the presentation are ordinary cell division, mitosis, karyotyping, and the cell cycle. These concepts are
necessary to understand the biology of cancer.
Here are some concepts that students should have a better understanding of after reading this chapter:
DNA structure, function, and replication;
RNA synthesis by transcription and post-translational modification;
the nature of the genetic code;
translation or protein synthesis;
posttranslational modification, packaging, and secretion;
the cell cycle, including control and mitosis;
cancer and its causes;
the laws of genetic inheritance;
and certain applications to population biology.
Topics for Discussion
Ask your students what they would suggest to a modern King Solomon, should he have to decide
which woman a child belonged to. The students should already be equipped with several approaches:
checking for certain phenotypic characteristics and karyotypes such as those mentioned in Saladin and
(pp. 134–136). Some students may also think of DNA fingerprinting or even of sequencing the DNA.
Students may be interested in looking at DNA fingerprints or even trying to perform one. Many
companies sell supplies and are usually willing to provide copies of actual DNA fingerprints using one
or another electrophoresis technique.
Have your students interview their family members to determine the prevalence of certain genetic traits
such as: eye color, widow’s peak, ABO blood type and Rh blood type (the two systems have loci on
different chromosomes), familial hypercholesteremia, familial Alzheimer disease, PKU, albinism,
breast cancer, prostate cancer, Huntington Disease, non-syndromic deafness, hemophilia, color
blindness, and sickle cell anemia. Some of these conditions are dominant, some recessive, some
blending, some autosomal, some sex-linked, and others are poorly understood at this time. They can
then draw up a pedigree to show how the condition has passed through the generations. Problems with
this approach can arise since some genes are masked, many phenotypic characteristics are controlled
by more than one locus, and numerous features are not always expressed (i.e., the penetrance issue).
Be aware also that not everyone has the father they think they have! A human genome chart,