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. 

Plants' Defense

On pages 80-83 in the "Hey, Bud, Can You Do Me a Fava?" section (chapter 4) Dr. Sharon Moalem describes how plants use toxins for defense against predators. He also shows how different plant toxins affect humans in parts of the world. Moalem uses examples in history to show the effects some plant toxins can have in humans. This relates to Big Idea 1 (the process of evolution drives the diversity and unity of life) because evolution is the reason that plants have toxins so they can survive and reproduce.

First, find a plant that is consumed by humans and contains a toxin. What are the effects of the toxin? Then, explain why farmers cultivate the Indian vetch (page 80) even if it contains a powerful neurotoxin. Describe how jimsonweed took a part in Bacon's Rebellion (page 81). Why do people accidentally eat jimsonweed every year? Afterwards, explain why people get a burning sensation when they eat certain types of peppers and why water does nothing to help it. If the average human eats somewhere between 5,000 and 10,000 natural toxins every year (page 83), what do you think are the reasons behind this?

(Tyler Hagen-thagen4@students.d125.org)

Infections during Pregnancy

On page 193, Dr. Moalem mentions that "more than half a million mothers die of complications resulting from pregnancy". Among the most common causes of death, including hemorrhage, pregnancy-induced hypertension, and pulmonary embolism, is infection. This relates to Big Idea 3: Living systems store, retrieve, transmit, and respond to information essential to life processes. It is essential for the immune system of  a birthing mother to respond to infections to avoid death.

Please explain why pregnant women and unborn babies are at high risk for some infections and diseases, and identify 2 specific infections prevalent among birthing mothers. Explain the process of fighting these infections, including each barrier of the immune system. Finally, explain how water birthing can prevent aspiration pneumonia in newborn children (page 203).

HERV, Psoriasis, Healthy Placenta, HIV

On pages 149-150, Dr. Moalem discuses the importance of retroviruses and viruses in the evolution of human beings. This relates to Big Idea 1 (The process of evolution drives the diversity and unity of life) because in humans, it is found that 8% of the human genome is composed of retroviruses, or elements related to it that have found a permanent place in our DNA. Specifically, it is noted that a healthy placenta is a benefit from HERV and the skin disorder psoriasis is not.


Describe how the virus is able to be a part of the human DNA (offspring's DNA). Define and explain what a Weismann barrier is and how it relates to viruses/ retroviruses? How does a virus/retroviruses cross this barrier. Explain how the Weismann barrier keeps out certain viruses/retroviruses.  Explain how the benefit of a healthy placenta is created. Explain how a hurtful effect of HERV, like psoriasis is created. Connect this with HIV. Compare and contrast the processes, effects, functions between HIV and HERV. Is HIV a type of HERV.


Crystal Chang (cchang3@students.d125.org)

First discovery of vaccines

On pages 125-126, Dr. Moalem described the first discovery of a vaccine by Dr. Jenner after he noticed that milkmaids with cowpox were more resistant to the deadly disease, smallpox, compared to other people within the same community. This relates to Big Idea 3: Living systems store, retrieve, transmit, and respond to information essential to life processes.

From the information from this experiment, explain what vaccination is in your own words. Determine why Dr. Jenner used a scrape of a cowpox sore for infecting the teenage boys compared to any other body fluid such as saliva. What happened when the boys were injected with the cowpox sore in terms of the ability of the smallpox to affect the boys. Be sure to use words such as antigen, antibodies, and memory cells. Describe how genes change in order to produce new antibodies for a new infection. Find another vaccine which is produced by infecting someone with a mild disease whose virus is similar to a deadly disease.

Prince Morkeh (pmorkeh4@student.d125.org)

Aging and Cancer cells vs. Stem cells

On pgs 183-189, Dr. Moalem explains how humans have genetic controls for aging. Cells have evolved to reproduce under a limit. Cells start to die off after reaching this limit and aging starts to take its toll. Cancer, on the other hand, involves cells that avoid this reproducing limit and become immortal cells. This relates to Big Idea 1: The process of evolution drives the diversity and unity of life.

The Hayflick limit is an example of an aging mechanism used by cells.

Using pgs 183-189, define the Hayflick limit explain how normal cells have evolved in relation to aging. Cancer cells on the other hand, are able seemingly able to reproduce infinitely with the use of telomerase. Using information from earlier units and pgs 183-189, explain how telomerase helps avoid this evolutionary reproduction limit, and why cancer cells are deadly. Finally, stem cells, like cancer cells, use telomerase to become immortal. Using pgs 188-189 and further research online, explain why stem cells can be beneficial despite the fact that they reproduce outside the Hayflick limit.

Submitted by Weilly Tong (wtong4@students.d125.org)

Antioxidants and Malaria Susceptibility?

On page 71 Dr. Moalem describes G6PD as a "bouncer" that kicks free radicals out of red blood cells. Free radicals are compounds with incomplete valence shells that can destroy red blood cells without G6PD.  Dr. Moalem then mentions G6PD deficiency, or favism, is an evolutionary adaptation to malaria.

Explain the biochemical reaction that requires G6PD to remove free radicals from hemoglobin. NAPDH plays a role in this reaction; where have we seen NADPH before, and how is it behaving differently now? Why might antioxidants, normally associated with good health, increase the severity of malaria in the body of someone with favism?

This question relates to Big Idea #4 (biological systems interact and result in complex properties) because G6PD interacts with free radicals resulting in electron transfer from G6PD to an acceptor, (un)ruptured hemoglobin, and malaria susceptibility.

Aidan Murphy, amurphy4@students.d125.org

Immune System

On pages 144-145, Dr. Moalem discusses the immense diversity of the immune system. His discussion relates to Big Idea #3 (Living systems store, retrieve, transmit, and respond to information essential to life processes), as the millions of different antibodies are created by the immune system in response to the threats that come from viruses and other microbes.

First of all, how is it possible for these millions of unique antibodies to be created when there are only about 25,000 active, coding genes? Explain this process using Dr. Moalem's description of the V(D)J recombination mechanism. How is the V(D)J mechanism similar or different to the mechanism jumping genes use, and what are the overall evolutionary implications of these adaptable mechanisms? V(D)J is not the only process the immune system uses to react to different threats - research another mechanism that the immune system uses to combat threats, and discuss how that mechanism works.

(Posted by Matthew Zhang; mzhang4@students.d125.org)

Predictive Adaptive Response

On page 160-162, Dr. Sharon Moalem begins his discussion of animals who have the ability to produce offspring based on the mother’s experience during pregnancy. Dr. Moalem gives four examples- the vole, the water flea, the locust, and the lizard. In each case the DNA is expressed differently based on what the mother senses in the environment. For the vole in particular, the mother is able to give birth to a baby either with a thick coat or a thin coat. In a way, this mother vole is able to determine if the baby will need to a thick coat for the winter or a thin coat if the environment is relatively hot. Scientists have labeled the mother’s experience to influence gene expression as a predictive adaptive response or maternal effect.

Explain how it is possible for the mother vole to produce a thick coat or a thin coat for a baby- include “turn on”, “turn off”, DNA in your explanation and discuss the epigenetics involved in this process. Give one more example of an animal that is able to determine what the phenotype the child will have because of the environment and explain how it relates to the vole. Include the implications that this would have on humans, and decide if it is possible. Discuss the validity of child obesity being an example of maternal effect through sources such as Dr. Moalem and outside sources. Finally, relate it to big idea 1, and explain how this process drives the diversity of life and explain how it can be a selective advantage while discussing the implications of the overall population. (Provide Examples from multiple sources.)

Rahul Kosgi (rkosgi4@students.d125.org)