As sperm are transported through the ducts system, what secretions are added from which three sets of glands to make up semen?
What will be an ideal response?
The seminal vesicles secrete fructose, a sugar that serves as an energy source for the sperm, and prostaglandins, locally acting chemical messengers that stimulate contraction of the female reproductive system to assist in sperm movement. The prostate gland secretes a milky, alkaline fluid that neutralizes acidic vaginal secretions and enhances sperm viability. The bulbourethral glands secrete a mucuslike substance that provides lubrication for intercourse. Together, the sperm and these various glandular secretions make up semen, a mixture that is about 95% secretions and about 5% spermatozoa.
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Glucose enters cells by
A. osmosis. B. diffusion. C. facilitated transport. D. active transport. E. receptor-mediated endocytosis.
You've just isolated a new bacterium in pure culture, and you culture it on a general purpose medium where its cells have a rod-shape (bacillus) morphology. In addition to culturing it on solid media, you inoculate a slide to grow it as a biofilm. When you use confocal microscopy to image the biofilm, you observe that there are several cellular morphologies, ranging from coccus to coccobacillus to long bacillus. The best explanation for this observation is that
A. the confocal microscope is out of adjustment. B. the biofilm is no longer a pure culture of the microbe. C. the biofilm culture was not incubated under the appropriate conditions. D. the microenvironments within a biofilm promote structural variation.
Cytosine and thymine are the two types of bases found in DNA known as ______________________. Fill in the blank(s) with the appropriate word(s)
Termination of translation and release of the polypeptide chain occurs when
a. tRNA binds to a termination codon via a complementary anticodon but lacks an amino acid. b. a protein release factor binds to the termination codon. c. a tRNA with a complementary anticodon binds to a termination codon, and a release factor bound to the CCA end releases the chain. d. a small molecule shaped like puromycin binds to the termination codon.