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)

Fetal Development and Epigenetics

In relation to Big Idea 3, which is “Living systems store, retrieve, transmit, and respond to information essential to life processes”, Dr. Moalem writes about epigenetics with fetal development from pages 162-165 and how the first few days after conception can have a huge impact on the growth of the fetus after once it’s born. Dr. Moalem uses the example of childhood obesity being a result of bad nutrition of the mother which are epigenetic signals for the fetus. Explain how bad nutrition in pregnant mothers today lead to children becoming obese. Define the term “epigenetic” and “phenotype” in your answer. Afterwards, research another medical condition that could be a result of epigenetics in fetal development and explain how that works.

(Jenny S. Li - jesli4@students.d125.org)

Capsaicin's effects on different animals

On pages 82-83, Dr. Moalem describes how raw habanero peppers have a burning chemical called capsaicin. This relates to Big Idea 1, the process of evolution drives the diversity and unity of life, because this capsaicin has evolved to affect mammals but not birds.

Capsaicin is characterized as a sticky poison. Describe what this means, how it affects mammals, the best way to ease and prevent these effects in mammals, and how it affects birds.  Also, explain why affecting birds and mammals differently is a selective advantage for the habanero peppers. Besides the burning sensation, what other effects can capsaicin can have on mammals’ bodies in large quantities?

Metabolism

On pages 68- 70 Dr. Maolem talks about a gene in the human body, CYP2D6 and how it can have a major impact on the body. This relates to Big Idea #2, which states: Biological systems utilize free energy and molecular building blocks to grow, reproduce, and to maintain dynamic homeostasis; CYP2D6 is an important gene affecting how the body metabolizes more than 25% of all pharmaceuticals. People who only have very few copies of this gene are considered ‘slow metabolizers’.

Explain in detail what the CYP2D6 gene is and does. Why are too many copies of this gene harmful to the body? What are the advantages and disadvantages for having more or less copies of this gene? Which chromosome is the gene located on? Is this a genetic disorder? If so, explain what type of genetic disorder is it and how it affects the allele frequency. Finally, explain what relation this gene has to Parkinson’s disease and please cite a source.

Pranathi Merneedi (pmernee4@students.d125.org)

Bacteria in Humans

Streptococcal bacteria - On page 112, Dr. Moalem describes streptococcal bacteria which are responsible for a wide range of human diseases. They exhibit a phenomenon called molecular mimicry in order to trick the immune system. The bacteria are able to mimic heart, joint, and even brain cells in humans. This relates to Big Idea 4 (biological systems interact, and these systems and their interactions possess complex properties) since the bacteria's interaction with cells in the body leads to the immune system producing antibodies in an attempt to rid the body of the invaders.

First define what is molecular mimicry, and does it relate to either of the two types of mimicry we had learned in a previous unit (batesian or mullerian mimicry)? Also describe what type of symbiotic relationship the bacteria has with its host. Then pick one of the type of human cells the bacteria can mimic (heart, joint, or brain) and describe two consequences resulting from the attack of the immune system towards this region of the body.

Finally, describe the type of antibodies our immune systems use in order to combat the streptococcal bacteria and how they fight the bacteria.

Faith Teodoro (fteodor4@students.d125.org)

MDS and Methylation

On page 175 Dr. Moalem discussed drugs that were designed to affect methylation patterns, in addition to drugs that cause methylation. To give an example of one such drug, he described azacitidine. This drug is used for the treatment of myelodysplastic syndrome, or MDS.  Explain how azacitidine relates to methylation. Also, MDS is described as a collection of blood disorders, therefore describe the major blood disorders that comprise MDS and explain the symptoms. The relationship between azacitidine and MDS relates to Big Idea 4 (Biological systems interact, and these systems and their interactions possess complex properties) because azacitidine and MDS interact to treat a patient.