The CFTR gene, on human chromosome 7, encodes an ion channel protein that regulates chloride ion concentrations. Mutations that disrupt CFTR function may lead to a disease called cystic fibrosis. How many copies of the CFTR gene are present in a cell that is... In G1 of the cell cycle
In G2 of the cell cycle
In a sperm cell
In prophase I of meiosis In a primary spermatocyte In a second polar body
In a recently fertilized zygote

What sentence best supports the statement that hormones are involved in the regulation of homeostasis? a. the hormone erythropoeitin increases the production of red blood cells when oxygen levels are low. b. the hormone oxytocin promotes labor contractions of the uterus during childbirth. c. the hormone melatonin induces sleep and its production is slowed by exposure to light. d. the hormone cortisol suppresses the immune system and is produced when the body is under stress.

Awoman whose sister tested positive for a specific mutation in the brca1 gene, which increases the risk for breast and ovarian cancer, is found not to have that mutation but does have a mutation of unknown significance near the known mutation site. how should this woman be counseled? select one: a. she should be informed that her risk for breast cancer is greater than the general population but not as great as her sister’s risk. b. she should be informed that because she does not have the mutation, her risk for breast cancer is not greater than that of the general population. c. she should be informed of her gene mutation status and be presented with all the available prophylaxis options and reconstruction options. d. she should be informed that she does not have the specific mutation but that because another mutation is present she should be vigilant about screening

Which step is not included in the step approach to calculating the greatest common divisor?