Biology Question

The cystic fibrosis gene encodes a chloride channel protein necessary for normal cellular functions. Let us assume that if at least 5% normal channels are present, the affected individual has mild symptoms of cystic fibrosis. Having less than 5% normal channels produces severe symptoms. At least 50% of the channels must be expressed for the individual to be phenotypically normal. This gene has various mutant recessive alleles: Predict the percent of functional channels and severity of symptoms for the following genotypes: a. heterozygous for CF100 b. homozygous for CF100 c. heterozygous, with one copy of CF100 and one of CF3 d. heterozygous, with one copy of CF1 and one copy of CF3

Which of the following mutations will result in cancer? a. homozygous recessive mutation in a tumor-suppressor gene coding for a nonfunctional protein b. dominant mutation in a tumor-suppressor gene in which the normal protein product is overexpressed c. homozygous recessive mutation in which there is a deletion in the coding region of a proto-oncogene, leaving it nonfunctional d. dominant mutation in a proto-oncogene in which the normal protein product is overexpressed

Mutations Can Uncouple chromosomal Sex from Phenotypic Sex Discuss whether the following individuals (1) have male or female gonads, (2) are phenotypically male or female (discuss Wolffian/Mllerian ducts and external genitalia), and (3) are sterile or fertile. a. XY, homozygous for a recessive mutation in the testosterone biosynthetic pathway, producing no testosterone b. XX, heterozygous for a dominant mutation in the testosterone biosynthetic pathway, which causes continuous production of testosterone c. XY, heterozygous for a recessive mutation in the MIH gene d. XY, homozygous fora recessive mutation in the SRY gene that abolishes function

Fragile-X syndrome causes the most common form of inherited intellectual disability. What is the chromosomal abnormality associated with this disorder? What is the phenotype of this disorder?

Theodor Boveri predicted that malignancies would often be associated with chromosomal mutation. What lines of evidence substantiate this prediction?

What are the roles of cellular proto-oncogenes, and how are these roles consistent with their implication in oncogenesis?

Control of gene expression in eukaryotic cells occurs at which level(s)? a. only the transcriptional level b. epigenetic and transcriptional levels c. epigenetic, transcriptional, and translational levels d. epigenetic, transcriptional, post-transcriptional, translational, and post-translational levels

Transcriptional regulators are proteins that bind to promoters (the 5-flanking regions of genes) to regulate their transcription. Assume that a particular transcription regulator normally promotes transcription of gene X, a transport protein. If a mutation makes this regulator gene nonfunctional, would the resulting phenotype be similar to a mutation in gene X itself? Why or why not?

List the regulatory mechanisms that might be lost in a cell producing faulty p53.