Skip to Main Content

Chapter 2. Information Flow and Levels of Regulation

Different types of RNA can play a role in which of the following processes:

A. DNA replication.

B. Enzymatic/catalytic functions.

C. Secondary messengers for cell membrane receptors.

D. Endocytosis.

E. Synaptic communication.

A is the correct answer.

Different types of RNA play a role in an amazing breadth of functions. RNA participates in DNA replication as described in the text: "DNA polymerase III can use the 3′-OH position of an RNA nucleotide as a point for attaching the first DNA nucleotide." RNA is not involved in the other four listed processes.

Which is the best example of pleiotropy?

A. One patient with neurofibromatosis has only a few hyperpigmented spots. A second (unrelated) patient has multiple tumors including spinal tumors that cause extreme pain.

B. A patient who carries a mutation inherited from a parent who is affected with a medical condition due to the mutation shows no expression of the condition themselves.

C. A mutation in the SOS1 gene produces Noonan syndrome. Patients with Noonan syndrome have short stature, heart malformations, dysmorphic facies, and learning difficulties.

D. A mutation in one part of gene produces one clinical problem. A mutation in another part of the gene produces a completely different problem.

E. A specific gene change causes no clinical problem.

C is the correct answer.

Pleiotropy refers to multiple effects (consequences) of a genetic change. The other answers are incorrect because:

  • A. Describes variable expression.

  • B. Describes incomplete penetrance.

  • D. Describes site-specific mutation expression.

  • E. Describes a benign polymorphism.

It is estimated that humans only have 22,000 functioning genes. Much simpler organisms have many more functioning genes. A major reason that the more complex human development can occur with fewer genes is:

A. the presence of multiple pseudogenes per each copy of a 'real' gene.

B. posttranslational modification of produced proteins.

C. gene amplification.

D. single splicing options.

E. epimerases.

B is the correct answer.

The other answers are incorrect because:

  • A. By definition, pseudogenes do not code for any known functional protein.

  • C. Gene amplification is a function of the ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.