Epigenetics

On pgs 162-163, Dr. Moalem explains how epigenetics plays a role in birth defects. The earlier epigenetic signals are transmitted, the more significant the potential changes are in the fetus. So scientists have discovered that the most critical period are the few first days after conception. For example, if a newly pregnant mother spends the first weeks of her pregnancy eating junk food, the embryo may receive signals that its going to be born into a harsh environment where critical food types are scarce. In response, certain genes are turned on and off and the baby is born small to compensate for the lack of food it needs to survive. This relates to Big Idea 4: Biological systems interact, and these systems and their interactions possess complex properties. There is an interaction between the environment (what the mother is consuming) and the living organism (the fetus), which results in the movement of matter (epigenetic signals).

The Barker Hypothesis is an example phenotype is the physical expression of your genotype.

Using pgs 162-163, explain his hypothesis correlates with epigenetics and birth defects. Also, using information from earlier units and pgs 162-163, explain why the first days after conception are most imperative. Finally, name some of the implications of epigenetics using pgs 162-163 and furthering research online

Submitted by Josh Baker (jbaker3@students.d125.org)

Evolutionary Pressures

On pages 62-63, Dr. Moalem discusses the idea that as humanity has evolved, different groups of humans encountered widely different circumstances, It was stated that dense hair on the forearms and legs may have been a defense mechanism against malaria carried by mosquitoes. This relates to Big Idea 1 (The process of evolution drives the diversity and unity of life) because the densest hair was generally found in the same places where malaria was most common-Italy, Greece, and Turkey.

How does the information regarding evolutionary pressures in the book help scientists in finding out whether these evolutionary traits were beneficial? Find two more examples from the book regarding evolutionary pressures that led to positive changes in a population. Research, for one of the examples, how your pressure can lead to a positive impact for populations over time.

(Josh Baker, jbaker3@students.d125.org)

rickets vs. spina bifida

On pages 50-52 the relationship between vitamin D, cholesterol levels, and sunlight were all discussed. It was stated that vitamin D is a unique type of vitamin because it can actually be naturally made within the body given the right amount of exposure to sunlight. This process is made possible with cholesterol in the body as the system portrays Big Idea 2 (Biological systems utilize free energy and molecular building blocks to grow, reproduce, and to maintain dynamic homeostasis) as cholesterol is converted vitamin D.

However, too much of something is not always a good thing, and such is the case for sunlight. Although sunlight and cholesterol levels have an inverse relationship, too much exposure to UV radiation from the sun can actually be damaging in the sense that it can lead to things like skin cancers and spina bifida in newborn infants. In your personal opinion, which extreme seem to reflect off of your lifestyle choices? Which would you then prefer? Do you think that it's a matter of regulating the intensity and amount of too little or too much sun that causes such problems? If so, what would be the fine balance in your opinion, especially if there are other means for the body to gain vitamin D (and what are those other means)?

(Lois Kim, lokim3@students.d125.org)

Methylation & Cancer

On pages 170-173,  Dr. Moalem explains how the methylation of PITX2 can be an indicator  of breast cancer recurrence  Ninety percent of women who have low methylation of PITX2 are cancer-free after ten years. Only sixty-five percent of women with high methylation of PITX2 were as lucky. Methylation relates to Big Idea 3, living systems store, retrieve, transmit, and respond to information essential to life processes. How does the information regarding PITX2 in the book help scientists treating patients who have had breast cancer? Find two more example from the book regarding methylation of genes that are red flags for cancer and explain how scientist use this information to their advantage. Include hypermethylation, methylation, and epigenetics. Research for one of the examples of how methylation can lead to different remedies besides chemotherapy.

(Lily Barghi lbarghi4@students.d125.org)

Phytoestrogens

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)

Anemia

On pages 19-21, Dr. Moalem discusses how disease may do us more benefit than good. Specifically, he mentions anemia as an example of this. Dr. John Murray, a doctor working in a Somalian refugee camp, found that the population did not display the harmful effects of various infectious diseases.
Briefly describe the correlational study that Dr. Murray did on the refugees in the camp by defining the independent and dependent variables. What did he find?
Based on Dr. Murray's experience, as well as the effects of iron supplements in the Maori people, anemia could be a benefit, rather than a hindrance. Iron seems to give a boost to the harmful bacteria that can plague us, rather than helping our own bodies.
Look up the symptoms of anemia, as well as the symptoms of botulism (a disease that Dr. Moalem mentions is more likely occur in infants who receive iron supplemented formulas) and state them here. Would you rather have anemia, or contract botulism, and why? Keeping in mind Big Idea #1 (The process of evolution drives the unity and diversity of life), explain why anemia could have developed in humans over time. Why would anemia be an adaptive trait?

Carolyn Fan, cfan3@students.d125.org

Psoralen and other Light-Reactive Chemicals

Psoralen, a toxin produced by celery plants to defend itself against attack, is mentioned by Dr. Moalem on pages 86-87. When ingested, it causes extreme light sensitivity in humans and possible DNA and tissue damage. One of psoralen's notable properties is that it is only reactive when exposed to sunlight, which is the reason why some insects roll themselves up in a leaf and eat the celery plant from the inside out; no sunlight reaches the place that they eat so no harmful reactions take place. Although Dr. Moalem notes that normal celery isn't very harmful when eaten by humans, psoralen's light-reactivity is an interesting property worth looking at. This relates to Big Idea 4 (Biological systems interact, and these systems and their interactions possess complex properties) because the consumption of plants such as celery by other organisms, including insects and humans, is an example of biological systems interacting. This may or may not be harmful to the other organism, depending on the presence of light, which is an example of a complex property.

Using your knowledge from the biochemistry unit and any other knowledge, what is the reason why sunlight makes psoralen so reactive? Find out how exactly psoralen is able to damage DNA and tissues. Then, find an example of another chemical that exhibits light-reactivity. Psoralen isn't just known for being a toxin. It's also used in processes such as treatment of skin problems in conjunction with UV radiation and as a tanning activator in sunscreens. Brainstorm another possible beneficial use of a light-reactive chemical such as psoralen.

Austin Hua (auhua4@students.d125.org)