Chapter 11: Gene Expression. 11-1 Control of Gene Expression. 11-2 Gene Expression and Development. 11-1 Control of Gene Expression. I. Role of Gene Expression (3 Key Points). Cells use different genes to build different proteins.
11-1 Control of Gene Expression
11-2 Gene Expression and Development
I. Role of Gene Expression (3 Key Points)
(1)A molecular biologist isolates mRNA from the brain and liver of a mouse and finds that the two types of mRNA are different. Can these results be correct or has the biologist made an error? Explain your answer.
(2)What region of a prokaryotic gene is analogous to the ENHANCER region of a eukaryotic gene?
(A) Structure of a Eukaryotic Gene
I. Cell Differentiation
Ex: In fruit flies, each homeotic gene shares a common DNA sequence of 180 b.p.; this specific sequence within a homeotic gene regulates patterns of development (i.e., a homeobox)
(3)Why might X rays be more dangerous to an ovary or a testis than to muscle tissue?
(4)Mutations may occur in gametes or in body cells. In which cell type is a mutation likely to be a source of genetic variation for evolution? Why?
(1) The operator region of a prokaryote is analogous to the enhancer region of a eukaryotic gene. Both operators and enhancers act as a switch that must be turned “on” to activate the expression of a gene.
(2) The ovaries and testes contain rapidly dividing cells that will become egg and sperm cells, respectively. A mutation due to X-ray exposure could thus be passed on to offspring.
(3) The results are probably correct because different genes were expressed in the brain and liver tissues, resulting in the production of two types of mRNA.
(4) A mutation in the gametes is likely to be a source of genetic variation because gametes pass on the mutation to the next generation when forming the zygote.