The Argument—In the flowcharts on page 31, it is shown that
the environment can affect a person’s traits by affecting the genes, proteins,
and cells to become traits. Give some environmental examples of how the
environment can affect each of these stages on its way to forming a beneficial human trait or a disease (refer to page 25). Also, what are some hormones that may be triggered by the environment
that help to alter our genes, the proteins made by our genes, and the cells
made by those proteins? State specific hormones in the human body and describe
the process. How would this ultimately affect someone’s traits?
(Christina Li, christinali208@gmail.com)
One example of how environment can affect gene expression is cell mediated immunity. The cytokines and other chemicals that are released are like hormones except that they are short distance and activate cytotoxic T cells by changing gene expression (Campbell). Another example of how the environment can affect traits is bacteria forming resistance, called endospores. Bacteria dont suddenly develop resistance, for example, to a nutrient lacking environment very quickly without a mutation, unless placed in an unfavorable environment. Being placed in that kind of unfavorable environment may cause the bacterial cells to code for proteins that surround the copied chromosome with a protective wall and the resistant cells, called endospores, has a higher change to survive for a much longer time with for example, a slower metabolism, allowing for a better chance of survival and reproduction in an unfavorable condition. Not only can this relate to evolution, it also can be associated with homeostasis due to the bacteria cell making a protective layer and thus slowing down its metabolism when in an unfavorable condition to maintain other necessary processes within the cell.
ReplyDeleteThe adrenaline hormone is triggered by environmental situations. Adrenaline is the fight or flight hormone. When we are in or perceive to be in a dangerous situation, environmental trigger adrenaline is released from the adrenal glands (situated above the kidneys). it increases the supply of oxygen and glucose to the brain and muscles is increased while suppressing unnecessary bodily functions such as digestion. (http://www.kidpowervancouver.org/id40.html). Adrenaline affects body tissues and tissue expression of adrenergic receptors. It also causes increased muscle contractions by changing gene expression in muscle cells. Adrenaline stimulates glycogenolysis in the liver and muscle, and glycolysis in muscle by changing gene expression in those organs to produce more enzymes to break the macromolecules down.
A way that environment can directly affect someone's traits is for example, if the parents interact in ways like reading and talking to a child, cell-specific gene expression can be influence to produce a cell called glia which secretes proteins that promote synapse formation. So then neural connections in the frontal lobe which controls emotion, can be strengthened and emotional regulation begins to develop. (http://med.stanford.edu/news_releases/2005/february/glia.htm) And this can ultimately affect someone's traits because of how the child would develop emotionally.
(mindy shaw, mindyshaw95@yahoo.com)