Answer:
d. raise the apparent value of the equilibrium constant, L.
Explanation:
Allosteric regulation is a type of regulation of an enzyme by binding an effector molecule at a site other than the protein's active site (i.e., the allosteric site). The equilibrium constant (L) refers to the transition between two forms of an allosteric protein in absence of a ligand. The properties of allosteric enzymes are explained by conformational changes associated with a low-affinity tense (T) state, or a high-affinity relaxed (R) state. Negative allosteric effectors are molecules that bind to the allosteric site on an enzyme in order to decrease its activity, thereby leading the enzyme to a low activity T state and thus increasing the value of the equilibrium constant.
Gynecomastia is an increase in the size of the mammary gland in men. The condition can occur in one or both breasts. It starts as a small mass under the nipple, which can be sensitive. One breast can be bigger than the other. Its cause is an imbalance between the stimulatory effects of estrogen (female sex hormones) and the inhibitory effects of androgens (male sex hormones) in the breast tissue, when the first ones increase, or the second ones descend.
Gynecomastia is a problem relatively common in the population, and there are three prevalence peaks throughout life:
Newborns: Between 60 and 90% of newborns have gynecomastia, produced by the passage of maternal estrogens through the placenta. It is a transient gynecomastia that disappears in about 2-3 weeks.
Puberty: Gynecomastia in puberty affects mainly young people aged between 10 and 14 years, and is due to the transient and physiological increase in estrogen that occurs at this age.
Elderly: Is due to an increase in fatty tissue with a greater peripheral aromatization ( a process that occurs in adipose tissue and that involves the conversion of androgens into estrogens), a decrease in the production of testosterone by the testes and the use of drugs.
Answer:
Embedded in the lipid bilayer are large proteins, many of which transport ions and water-soluble molecules across the membrane. Some proteins in the plasma membrane form open pores, called membrane channels, which allow the free diffusion of ions into and out of the cell.
Parasitism; the tick benefits from the human, the host.
