In humans, clear gender differentiation occurs, not at fertilization, but after the second month of gestation. What is the first event of this differentiation?
A) formation of testosterone in male embryos
B) formation of estrogens in female embryos
C) activation of SRY in male embryos and masculinization of the gonads
D) activation of SRY in females and feminization of the gonads
C
You might also like to view...
If a sperm cell combines with an egg cell, then the result is a
A. gamete. B. diploid cell. C. duplicated chromosome. D. gametophyte. E. haploid cell.
The reason humans inhale oxygen is so that it can be used for:
What will be an ideal response?
The combination of villi and microvilli provides the small intestine with ____
a. a large surface area for digestive functions b. elastic properties c. a high enzyme producing capacity d. motility e. sensitivity to chyme contents
In Drosophila, the hunchback gene encodes a protein (HB) that is required in the correct concentrations for proper segmentation of the embryo. In the zygote and embryo, the expression of hunchback is stimulated by high concentrations of Bicoid protein. You manipulate a Drosophila embryo to have high Bicoid concentrations throughout. Which of the following would occur?
A. The HB protein would be produced throughout the entire embryo. B. The HB protein would not be produced at all. C. The HB protein would be produced throughout the entire embryo and segmentation would not occur correctly. D. The HB protein would not be produced at all and segmentation would not occur correctly. E. Segmentation would not occur correctly.