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【多选题】
What is the physiological role of retinoid hormones ?A.
The retinoid hormones are potent hormones that regulate the growth, survival, and differentiation of cells via nuclear retinoid receptors. The prohormone retinol is synthesized from β-carotene, primarily in liver, and many tissues convert retinol to the hormone retinoic acid (RA).
B.
RA binds its specific receptor (RAR) in the nucleus, forms a dimer with another nuclear protein, retinoid X receptor (RXR), and alters the rate of expression of genes responsive to R
C.
All tissues are retinoid targets, as all cell types have at least one form of nuclear retinoid receptor. In adults, the most significant targets include cornea, skin, epithelia of the lungs and trachea, and the immune system, all of which undergo constant replacement of cells.
D.
RA regulates the synthesis of proteins essential for growth or differentiation. Excessive vitamin A (the precursor to retinoid hormones) can cause birth defects, and pregnant women are advised not to use the retinoid creams that have been developed for treatment of severe acne.
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【单选题】听力原文：You may telephone me if there is still something wrong with your car and we can arrange for you to collect it. The speaker promises to
A.
collect the car.
B.
correct the car.
C.
arrange the car.
D.
telephone the owner.
【简答题】Why do you ___ in me like that? What are you and she to me? Do you think, because I am poor, ___, plain, and little, I am soulless and ___? You think wrong!- I have as much soul as you,- and full as m...
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