Describe the pathway of sperm during ejaculation, from production to exiting the body. Include the contributions of various accessory ducts and glands
What will be an ideal response?
Sperm are produced in the seminiferous tubules from spermatogenic cells within the testes. The Sertoli cells nourish the sperm and the interstitial cells produce testosterone. The immature sperm move to the epididymis where they mature. Upon ejaculation, they move to the vas deferens and then to the ejaculatory duct. Secretions from the prostate gland neutralize the acidity of the female reproductive tract. The bulbourethral glands add alkaline fluid to the sperm. Semen containing the sperm eventually exits the urethra outside the male's body.
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What is required for formation of the transcription initiation complex in eukaryotes?
A. binding of a transcription factor to the TATA box, followed by recruitment of additional transcription factors and recruitment of RNA polymerase II B. binding of a transcription factor to the transcription bubble, followed by recruitment of additional transcription factors and recruitment of RNA polymerase III C. binding of the sigma subunit to the start site followed by recruitment of RNA polymerase II D. binding of RNA polymerase II to the TATA box, followed by recruitment of transcription factors E. binding of the sigma subunit to promoter elements at -35 and -10, followed by recruitment of the core polymerase
A college student walks down New York City's Fifth Avenue at 8:00 AM. She is late for class so she catches the bus for the last 2 miles of her commute. Did she have a larger ecological footprint when she was walking or when she was on the bus?
A. on the bus, because it is using energy to move B. on the bus, because the road took more energy to build than the sidewalk C. walking, because she is using energy that must be replaced by eating foods that are not locally grown D. walking, because she is moving on a sidewalk that took energy and raw materials to build E. More information is needed about, for example, the number of people on the bus and its fuel source, to accurately determine her ecological footprint in both situations.
Which is an example of a quantitative trait?
A. People who are homozygous for the group of genes associated with skin pigment have either lighter or darker skin than those who are heterozygous for those genes. B. The alleles of the gene for red hair color is masked by the gene for brown hair color. C. A person heterozygous for dwarfism will always have the dwarf phenotype. D. A woman who has one allele for color blindness will not be color blind, but a man who has one allele for color blindness will be color blind. E. 25% of the offspring from a cross of two fruit flies that are heterozygous for curly wings will have curly wings.
Over evolutionary time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses?
A. Natural selection cannot account for losses, only for innovations. B. Natural selection accounts for these losses by the principle of use and disuse. C. The ancestors of these organisms experienced harmful mutations that forced them to find new habitats that these species had not previously used. D. Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.