Inherited change Flashcards
What is codominance?
Both alleles are expressed in the phenotype in heterozygosity.
Explain why two genes assort independently.
They are on separate chromosomes.
Each bivalent orients itself separately in metaphase I.
This gives four new combinations of alleles.
Explain the meaning of the terms haploid and diploid.
Haploid is one complete set of chromosomes.
Diploid is two complete sets of chromosomes.
Outline the main features of lac operon.
The operon has promoter.
The operon has operator.
The operon has 3 structural genes: lacZ, lacA and lacY.
Explain the role of lac I gene in the regulation of the lac operon.
The lac I gene is always expressed.
It codes for repressor protein.
Repressor protein binds to operator and block the promoter.
This prevents RNA polymerase from binding to promoter.
Lactose binds with repressor so promoter is unblocked.
Suggest and explain why it is an advantage to a prokaryote to have a repressible operon.
So that proteins that are necessary to the cell are made all the time. When the concentration gets too high, end product inhibition occurs.
