On pages 78-79, Dr. Moalem describes chemical defense mechanisms that plants employ in order to evade predators. The defense mechanisms of plants relate to Big Idea 2 (Biological systems utilize energy and molecular building blocks to grow, to reproduce, and to maintain homeostasis.) The growth and homeostasis of a plants are influenced by changes in the system’s environment.
Define phytoestrogens and describe their effect on animals. Specifically describe the effect of clover on grazing sheep during times of drought.
Explain how plant defense mechanisms are evolved adaptations. Research and describe other chemical plant defense mechanisms. Choose one chemical plant defense mechanism and explain how it functions on a molecular level.
Research how scientists have utilized phytoestrogens in the creation of birth control pills and how birth control functions in the human body in comparison with how phytoestrogens function in animals. Explain on a molecular level how disogenin, a phytoestrogen, was synthesized to create birth control. Finally, research the potential long-term effects phytoestrogen could have on humans and how these effects could lead to evolutionary changes.
(Taylor Young, tyoung3@students.d125.org)
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ReplyDeletePhytoestrogen is a group of chemicals found in plants that can act like the hormone estrogen. Estrogen is a hormone necessary for childbearing and is involved with bone and heart health in women. The phytoestrogen can act like estrogen at low doses but block estrogen at high doses. Phytoestrogen may affect communication pathways between cells, prevent the formation of blood vessels to tumors or alter processes involved in the processing of DNA for cell multiplication (http://envirocancer.cornell.edu/factsheet/diet/fs1.phyto.cfm).
ReplyDeleteThe clover produces a potent phytoestrogen called formononetin as a natural defense against grazing predator (78). Sheep consumed the clovers, which belongs to a group of plants that contains phytoestrogen. During times of drought, clover protects itself by limiting the size of the next generation of the predators (sheep). Then, the reduction of clovers will increase production of formononetin and prevent the birth of baby grazers by sterilizing their would-be parents.
The diversification of flowering plants during ancient periods is associated with the sudden burst of speciation in insects. This diversification of insects represented a major selective force in plant evolution, and led to selection of plants that had defensive adaptations. Plants have evolved many secondary metabolites involved in plant defense. For example, alkaloids are derived from various amino acids. Alkaloids have medical effects on humans and other animals. Some alkaloids can inhibit or activate enzymes, or alter carbohydrate and fat storage by inhibiting the formation phosphodiester bonds involved in their breakdown. Some alkaloids bind to nucleic acids, inhibit synthesis of proteins, and affect DNA repair mechanisms. Alkaloids can affect cell membrane and cytoskeletal structure causing the cells, which might lead to affect neurotransmission. This example of defense mechanisms of plants relate to Big Idea 2 (Biological systems utilize energy and molecular building blocks to grow, to reproduce, and to maintain homeostasis), unit 4: DNA, and also unit 12: Cell signaling.
The effects of phytoestrogen on women taking birth control pills or being treated with postmenopausal hormonal therapy have not been examined. Both of these treatments use estrogen, and since phytoestrogen can act like the hormone estrogen, phytoestrogen might disrupt or amplify the effect of the estrogen in individuals with a diet very high in phytoestrogen. (http://envirocancer.cornell.edu/factsheet/diet/fs1.phyto.cfm). However, to synthesize diosgenin, diosgenin should be chemically synthesized into a molecular structure that is same as the real human progesterone; this is the reason wild yam taken internally will not increase progesterone levels in the human body. The whole herb form of Wild Yam root, which contains diosgenin, cannot be biologically converted to hormones by our bodies. This can only be done in a lab chemically (http://natural-fertility-info.com/reproductive-system-support-for-women-with-wild-yam.html). Phytoestrogen may offer long-term protection against some cancers including breast, colon, prostate, liver, and leukemia. According to some animal studies, phytoestrogen eaten as part of an adult diet can protect against some types of cancer and may even inhibit tumor growth. People have been eating these compounds for thousands of years and may have evolutionary adaptations that allow them to use phytoestrogen to their advantage. And, some plant and soy products contain other potential anti-cancer substances that may be responsible for the proposed health benefits.
(Hyung Eun Lee, helee4@students.d125.org)