Answer:
Seminal vesicle
Explanation:
Seminal vesicle secretes an alkaline and viscous fluid that constitutes about 60% of the volume of semen. The fluid secreted by seminal vesicle contains fructose which is a monosaccharide sugar, prostaglandins, and clotting proteins. The alkaline nature of the seminal fluid neutralizes the acidic environment of the male urethra and the female reproductive tract. This is required as the acidic conditions inactivate and kill sperm.
The fructose sugar serves a fuel for ATP production by sperm. Prostaglandins are responsible for sperm motility and viability as they stimulate smooth muscle contractions within the female reproductive tract. Therefore, a malfunctioning seminal vesicle would result in low semen volume and reduced motility due to the scarcity of energy.
Answer:
G-protein-linked receptor
Explanation:
Epinephrine acts via G-protein-linked receptors. The heterotrimeric G proteins located within the cell are activated by G protein-coupled receptors that span the cell membrane. Signaling molecules bind to a domain on the GPCR located outside the cell, and an intracellular GPCR domain then in turn activates a particular G protein.
Answer:
Without an oxygen atmosphere very few things could live on the early Earth. Anaerobic bacteria were probably the first living things on Earth. The early Earth had no oceans and was frequently hit with meteorites and asteroids.
Explanation: