Online Plant Transpiration Lab

Here's the link for the online biology lab for plant transpiration.

Table

click on the graph for a larger view

Journal Questions

1) Describe the process of transpiration in vascular plants.
  The process of transpiration is the evaporation of water in plants through the stomata, which is located on the leaves for most plants.

2) Describe any experimental controls used in the Investigation.
  The experimental control is the transpiration rate of the plants in an hour under normal condition (room temperature and STP, without fan, heater or lamp)

3) What environmental factors that you tested increased the rate of transpiration? Was the rate of transpiration increased for all plants tested?
  The factors I tested that increased the transpiration rate are wind, heat and light. The increase in wind and heat increased the transpiration rate for all plants, but the light only increased the transpiration rate for arrowhead, coleus, devil's ivy, English ivy and geranium.

4) Did any of the environmental factors (heat, light, or wind) increase the transpiration rate more than the others? Why?

  For most plants, the wind increases the transpiration rate more than other factors because the wind will increase the movement of water on the leaves, while reducing the layer of water vapor (boundary layer) on the leaf surface. 

5) Which species of plants that you tested had the highest transpiration rates? Why do you think different species of plants transpire at different rates?
  Rubber plant has the highest transpiration rates. Different species of plants transpire in different rates because they adapt to different environments through evolution.

6) Suppose you coated the leaves of a plant with petroleum jelly. How would the plant's rate of transpiration be affected?

  It would decrease the transpiration rate because the petroleum will prevent the stomata on the leaf from opening and evaporating water.

7) Of what value to a plant is the ability to lose water through transpiration?

  Because of its ability of cohesion, the water, while being transferred up through xylem, can also carry nutrients up from the roots. After the water is evaporated, the upper level of plant can absorb the nutrients and grow larger. Also, transpiration can moderate the surrounding temperature of the plant and increase air humidity.

- Andy Liu '15

Stuff about plant hormones

  Today I learned about three hormones that are important to plant growth. The first hormone is the auxin (IAA), and one of its major effects on plants is to stimulate the cell elongation and growth through phototropism. It's usually transported through parenchyma tissue from the shoot apex to the base at the rate of 10 mm/hr, and its direction is related to polarity instead of gravity. One of the major sites of auxin synthesis occurs in apical meristem of the plant. Binding to a receptor in plasma membrane of plant cell, the auxin is responsible for stimulating cell elongation. However, the cell elongation slows down when a high concentration of auxin occurs, since the production of ethylene, inhibitor of cell elongation, is induced to maintain homeostasis. Other effects of auxins include root and fruit development and secondary growth in the vascular cambium. 

Phototropism

  The second hormone I learned is the abscisic acid (ABA). The major function of abscisic acid is to slow down plant cell growth, in contrast to the function of auxins. Also, the acid controls plant cell dormancy. When a plant begins to wilt, the ABA in plant accumulates and allows stomata to close rapidly to reduce cell respiration and water loss. The acid is also the primary signal for plant to withstand droughts because ABA will be transported from root when a water shortage occurs. 

  The last hormone I learned is the ethylene. I already mentioned before that it is the inhibitor of cell elongation, and it is usually produced in response to harsh weather conditions, plant injuries, fruit ripening and high concentration of auxins. The change in balance of ethylene and auxin controls leaf abscission. For example, an aged leaf will produce less auxins and become more sensitive to ethylene. As the leaf accumulates more ethylene, the leaf will produce enzymes that digest cellulose and parts in the cell wall. Also, ethylene will also trigger the triple response when there is pressure on the stem, which slows down stem elongation and induces the plant to grow horizontally in order to circumvent the obstacle in front. Finally, the ethylene is also a part of positive feedback system, where it triggers fruit ripening, while fruit ripening induces more production of ethylene. 

- Andy Liu '15

FLOWERS, FLOWERS EVERYWHERE!!!! (lol)

1. I found this type of flowers near the Alamo dorm, and there are several trees like this one on campus. As you can see, the flowers mostly grow on the lower level of the branches, so the leaves on top can block the strong sunlight for them. The flower are also very open to pollen transport.

  Because of its high density on the tree, and its bright red color, this type of flowers is proven to be very attractive to bees. I found this bee collecting pollen 3 minutes after I began my observation.

2. I found these pink roses right next to Mr. Quick's house. As you can see, the pink roses are very open to pollen transport as well. The thorns on the stem of these flowers are used primarily for defense against predators, which they developed throughout evolution.

3. I also found this type of flowers near Mr. Quick's house. Even though these flowers are lower than the two types above, their position at the top of the bushes make them completely exposed to the strong sunlight. Also, the bright color of the flowers makes them attractive to bees as well.

- Andy Liu '15

Analysis of the "Botany of Desire" introduction

http://www.mnn.com/earth-matters/animals/stories/bees-get-a-buzz-out-of-electricity-from-flowers

  Today, through my reading the introduction of the book "Botany of Desire", I learned a different perspective of our relationship with nature. In contrast to our traditional perspective of being the dominant species, the author introduced a new idea of co-evolutionary relationship. Just like how flowers use their colorful character to attract bees in order to spread their pollen, plants exploit our inner desire and influence our preferences through their tastes and appearances. 

http://cdn.oxwordsblog.wpfuel.co.uk/wpcms/wp-content/uploads/apple-e1382039006457.jpg

  In the introduction, the author provided examples like apple, tulip, cannabis and potato to support his statement. Apple exploit our desire with its sweetness; tulip exploit our desire with its beauty; cannabis exploit our desire through intoxication; potato exploit our desire with its taste. Also, these four plants are known as domesticated plants, which sounds ironic since the plants are the ones who manipulated our desire and developed an advanced strategy through evolution, in order to make themselves popular in human agriculture. 

http://www.emol.com/noticias/tecnologia/2012/01/17/522007/paleontologo-encuentra-trabajos-olvidados-de-charles-darwin.html

  Even though the perspective sounds novel and unique, the idea can be traced to Charles Darwin, the man who found theory of evolution. In the first chapter of his famous paper Origin of Species, Darwin introduced a term "artificial selection", which meant our choice in selecting domesticated species, that reflects on our will. He described that our desire plays the same role as the natural selection in determining the best species for survival, but he didn't foresee the trend of how artificial selection has now become the most powerful force of nature, and even stronger than natural selection.

"Human Imprint", Photo credit to Cheker Andouni, Source URL: http://500px.com/photo/21128787/human-imprint-by-cheker-amdouni

  Our relationship with nature has been interpreted in many different ways throughout history. However, this idea of reciprocal relationship has put us back into the nature's web. Instead of thinking of us as the dominant species on Earth, we should also admire the power of nature that induces us to select the best plants for survival, because perhaps in the eyes of nature, we're not that different from those bees. 

- Andy Liu '15

Graph analysis of wolf-rabbit simulation lab

  Today we did a simulation lab of predators and preys in class. The purpose of the lab is to find out the relations between number of predators and number of preys in a specific environment, and we used wolfs and rabbits as our subjects. We used large and small cards as our wolves and rabbits. In the first round, 1 large card and 3 small cards are put into the environment. Each time a wolf card is put into the environment, it has to touch three rabbit cards in order to reproduce, while the rabbit cards continue to reproduce each round. Here is our data after 10 rounds of simulation.

 As you can see, the number of wolves didn't grow until the 5th round, while the number of rabbits shows a significant increase during the first 5 rounds. The decrease in number of rabbits didn't start until the 7th round, which is when we begin to see a larger increase in number of wolves. I believe that this represents that the number of predators is directly proportional to number of preys in the beginning, but becomes more indirectly proportional as the number of preys begins to decrease while number of predators is rising.

-Andy Liu '15

Natural Disaster blog of Savanna biome -- Link Here!

Here's the link to my blog of what African savannas will look like if global temperature rises. Thanks!

-Andy Liu '15

My Biome Travel Blog

  Here's the link to my travel blog of Seregenti savanna in Tanzania, East Africa. Thanks!

- Andy Liu '15

Unit 9 Lab Report #1: A Pill Bug's Life

Tuck & Roll from A Bug's Life

Abstract

  For this lab, we are trying to find out what environment the terrestrial isopods (pill bugs) prefer to live by observing their behaviors. We collected 10 pill bugs and put them in a choice chamber, where two circular spaces of the same size are joined together. During the lab, the two sides of the chamber will be different from each other in only one aspect, while other conditions of two sides remain constant. By counting the number of pill bugs on the two sides and analyzing the data, we can find out which environment is more favorable to pill bugs.

Introduction

  To understand the purpose of this lab, one must first understand the definition of animal behaviors. The behavior is an animal's response to sensory input, and a behavior requires communication between animals through symbolic or chemical signals. In many cases, there are usually two types of explanations and questions for the behaviors. A proximate explanation or question relates to how the behavior occurs, and a ultimate explanation or question relates to why the behaviors occurs. Take an example of bird song, a proximate question for that behavior would be "How does the bird sing?", and an ultimate question would be "What is the purpose of bird song in nature?" 
  There are two categories for animal behaviors. The first category is innate behaviors, and it's categorized into reflexes and instincts. The reflex behaviors are the body's automatic responses to a stimulus, and they follow a neural pathway called the simple reflex arc. The arc often involves a sensory neuron, an association neuron and a motor neuron. The process of arc starts when the sensory neuron detects a stimulus, and the association neuron synapses with other neuron in order to send information to other parts of the body. Finally, the motor neuron responds to the stimulus in an effector cell, and the behavior occurs. The instinctive behavior is also the body's response to a given stimulus, but it's different from reflex because the behavior is not automatic, since the sensory neuron sends the impulse directly to the brain, and the brain have to respond to stimulus with account of the specific situation. 

Taxis movement - birds migrating to the south

  Orientation behaviors, a category for instinctive behaviors, are series of coordinated movements that are triggered by external stimuli. These behaviors include kinesis and taxis movements. The kinesis movement is an indirect motion in response to stimulus, and the pace of the motion is directly proportional to the intensity of the stimulus. An example of kinesis behaviors would be cockroaches scatter in random directions when there is a bright light shining upon them. The taxis movement, in contrast, is a specifically directed motion toward or away from the stimulus. An example of taxis movements would be the birds migrating to the south. The proximate cause of the migration would be the bird's ability to find directions with polarity in the Earth's magnetic field, and the ultimate cause of it could be the search for abundant food resources. 

Fixed action pattern - greylag goose rolling nearby eggs

  Some innate behaviors (especially instincts) followed fixed action patterns, which are stereotypical behaviors triggered by a sign stimulus in the surrounding environment, and completed once they begin. An example of fixed action patterns would be greylag goose, which continues to roll nearby eggs into the nest, even after the eggs are taken away. 

Imprinting behaviors - young geese mimicking their mother's actions

  The second category is learned behaviors, which include imprinting, classical conditioning, operant conditioning, habituation and insights. The imprinting behavior occurs when young animals go through a critical period when they follow the actions of parent animals. The example for imprinting behaviors would be young geese, which they follow the actions of their parents. A proximate cause for their imprinting behaviors may be that during their early development stage, the mothers of young geese choose to move away from the young geese and call them to begin the learning routine. The ultimate cause of those imprinting behaviors may be that young geese mimic the actions of their mothers to learn necessary skills, and survive in their habitat. 

Ivan Pavlov's experiment of classical conditioning

An alternative interpretation of the Pavlov experiment... by THE DOG

  The classical and operant conditioning are very similar learning behaviors for animals. Classical conditioning, also known as associative conditioning, is a behavior that the animal learns to link two unrelated stimuli together. A "classic" experiment on classical conditioning (haha) was done by Ivan Pavlov, a Russian Nobel-prize-winning scientist. In the experiment, the dog had no reaction to the tuning fork and drooled when the food is provided before the conditioning. During the conditioning, Pavlov provided food to the dog after he rang the tuning fork. After the conditioning is over, the dog would drool when it hears the tuning fork. The experiment successfully proved that animals can learn through conditioning or reoccurring events.   

The Skinner experiment on operant conditioning

  The operant conditioning is quite similar to classical conditioning. However, the behavior is also known as the trial-and-error conditioning because the animal receive rewards or punishment to learn the behaviors. An experiment was done by psychologist B. F. Skinner. In the experiment, Skinner taught the rat to press the lever by associating the action with the food reward. In contrast, he also taught another rat not to press the lever by electrifying the lever, and using it as a punishment. 
  Therefore, by observing the actions of the pill bugs moving to two sides of the chamber, we can determine whether their movements are innate or learned behaviors, thus discover which side of environment is more suitable for pill bugs. Finally, our question for the lab is "Do the pill bugs prefer the lighted environment or the dark environment?"

Hypothesis

  To answer the question, the independent variable of our lab should be the difference of light exposure on two sides of the chamber, and the dependent variable would be the number of pill bugs on each side. The constants in our lab would be the same size of two circles of the chamber, the total number of pill bugs, temperature and pH level. 
  In general, we hypothesized that if the pill bugs are put in two environments with different lighting, then the pill bugs will choose the dark environment, because dark environment has a higher humidity level than the lighted environment, which is necessary for pill bugs' survival in their habitat. 

Materials

1. two choice chambers
2. two pieces of filter paper
3. 10 pill bugs
4. a lamp
5. a paint brush
6. data sheet
7. timer

Procedure

the 10 pill bugs we collected in the 1st choice chamber

• At first, we put the 10 pill bugs we collected in one choice chamber. 
• Later, we placed two pieces of filter paper on both sides of the other choice chamber.
• Then, we moved the bugs to the choice chamber with filter papers with the paint brush.
• We turned on the lamp and put the left side of the chamber under the light.
• Later on, we covered the right side of the chamber with the first chamber we used, in order to block the light. 

This is what the setup looks like...

• Using the timer, we counted the number on each side of the choice chamber every 30 seconds. We stopped recording after 5 minutes of data.
• We turned off the lamp, moved the pill bugs into the stock chamber, and cleaned the choice chamber to finish the lab. 

Data
  

Click on the data to enlarge

Conclusion

  From our collected data, we can see that despite the trend of pill bugs moving toward the lighted side in the first and third minute, there were always more pill bugs on the dark side than those on lighted side, which proved our hypothesis correct. Thus, we concluded that the pill bugs are more comfortable living in dark environment than living in lighted environment. One mistake in our lab was that the difference between two sides of the chamber on the independent variable (lighting) is not apparent, since some pill bugs on the dark side of the chamber began crawling under the filter paper at 2 minutes after the lab started. 

Citation

    Magliore, Kim. The Princeton Review: Cracking the AP Biology Exam 2014. N.p.: Princeton Review, 2013. Print.

- Andy Liu '15

Responses of the Immune System Quiz

Explain how the immune system achieves all of the following.

1.       Provides an immediate nonspecific immune response

-          The immune system provides an innate and nonspecific immune response through the skin and mucous membrane, the first line of defense in immune responses.

-          Sweat glads make surface of the skin inhospitable to many microorganisms

-          Mucous membrane will create mucus to trap microbe and other particles

-          Mucus contain lysozyme that disrupts bacterial cell walls 

-          Chemical responses: ciliated epithelium (trap for pathogens), phygocytes (white blood cells that patrol circulatory system and absorb or send enzymes to destroy the pathogens)

2.       Activates T and B cells in response to an infection

-          Lymphocytes are the key cells in the immune system, and they are responsible for recognizing antigens.

-          B and T cells recognize antigens by means of antigen-specific receptors embedded in their plasma membranes.

-          B cells produce antibodies, which are specific responses to antigens

-          Phygocytes present antigens to Helper-T Cells, that activates B cells (Humoral Response) and T cells (Cell-mediated Response)

-          B cells differentiate into 2 populations: Plasma cells and memory cells

-          Clonal Selection: Once a specific antigen is presented to B-cells, they began to produce different antigen receptors. Only B cells with reactive antigen receptors are allowed to migrate and divide.

-          T cells differentiate into 2 populations: Cytotoxic T-cells and memory cells

-          Antigen Presentation: To respond to a specific antigen, T-cells must interact with a cell that presents the antigen with its MHC protein marker (all phygocytes, cells infected by specific pathogens and cancer cells)

3.       Responds to a later exposure to the same infectious agent

-          The Memory B and T cells activated will remain viable and circulate in lymphatic system in case of a future threat with same type of antigens.

4.       Distinguishes self from nonself

-          Every cell in your body carries a distinctive marker protein that is recognized as “self” and called Major Histocompatibility Complex (MHC)

-          The natural killer cells will not attack the other body cells because all of them carry the same MHC protein marker. 

- Andy Liu '15

"Helix Affinity" Podcast - HGH Hormone (Sochi Olympics Special) (Audio + Transcript)

3 types of chemical pathways

  Hey guys, here's the link to my podcast on HGH growth hormone if you want to listen. Below is the transcript, thanks for the support!

"Hey guys, welcome to another episode of 'Helix Affinity' podcast, and I’m your host Andy. And today, to celebrate the Sochi Winter Olympics, and continue our topic of the endocrine system, we will be talking about a hormone that can improve the performance of athletes, which is HGH, the Human Growth Hormone.

 This is a peptide water-soluble hormone that is responsible for cell regeneration, reproduction and growth of bones, muscles and other tissues. It is produced on the anterior pituitary gland in endocrine system.

 To understand how this hormone works, it is important to understand what “chemical pathway” means.

 The chemical pathway is a bio-chemical reaction that occurs in a cell. Photosynthesis, cell respiration, these reactions are both chemical pathways. So the pathway begins with a receptor that detects the stimulus and send the information to a control center, and the control center would send out a signal that directs at the target cell.     

 In the endocrine and neuroendocrine, two major types of chemical pathways, that signal would be the hormone. So, how exactly does the HGH work?

 The Growth Hormone has two types of effects. The first effect would be direct effect that the hormone binds the receptor on the target cells. An example would be adipocytes, the fat cells. With growth hormone receptors on the cells, HGH would stimulate the receptors to suppress the cell’s ability to accumulate lipids by breaking down triglycerides.

 Another effect of Growth Hormone would be indirect effect, that the hormone travels to the liver and induces the production of IGF-1, the insulin-like growth factor that creates a negative loop to stimulate amino acid uptake and protein synthesis in muscles and other tissues.

 The IGF-1 also takes part in the regulatory system of HGH, that high amount of IGF-1 stimulates the secretion of somatostatin, the inhibitor of HGH. Another regulator would be GHRH, the information of hormone that stimulates the production of HGH.

 So at this point you may wonder, what’s the difference between growth hormone and steroids? First of all, HGH is not for medical use, since it’s already in your body, while steroid is. Also, HGH is easier to absorb than steroids. It is not addictive, and has no side effects.

 With these characters, HGH is often revered as “fountain of youth”, but it is still restricted in the Olympics. Growth hormone injections have been used by athletes since 1982, and they are still banned by IOC and NCAA.

 Since the traditional urine test could not detect HGH, the law wasn’t enacted until early 2000s, when a new blood test found the difference between natural and artificial HGH. Finally, the blood test was first used in 2004 Olympics Games in Athens, Greece.

 Thank you for listening to the Olympic special episode of 'Helix Affinity', and we’ll see you next week, stay healthy. "

Feedback Loop of HGH hormone

Works Cited:

Bowen, R. "Growth Hormone." Growth Hormone. N.p., n.d. Web. 22 Feb. 2014. Retrieved from URL: http://arbl.cvmbs.colostate.edu/hbooks/pathphys/endocrine/hypopit/gh.html

"Steroids Forum: HGH & Peptides/rHGH/A Basic Guide to Human Growth Hormone."Steroids Forum: HGH & Peptides/rHGH/A Basic Guide to Human Growth Hormone. N.p., 31 Aug. 2012. Web. 24 Feb. 2014. Retrieved from URL: http://www.eroids.com/forum/hgh-peptides/rhgh/a-basic-guide-to-human-growth-hormone

"HGH (Human Growth Hormone): Uses and Side Effects." WebMD. WebMD, n.d. Web. 23 Feb. 2014. Retrieved from URL: http://www.webmd.com/fitness-exercise/human-growth-hormone-hgh

Background Music: Harder Better Faster Stronger by Daft Punk

- Andy Liu '15

Unit 7 Lab Report #1: The Reactions of Gelatin With Pineapple Enzymes in Different Heat Conditions

  Andy Liu
  Honors Biology - A
  Mr. Quick

  ABSTRACT
   For the lab, we tested the combination of strawberry-flavored jell-O with canned and fresh vegetables to see how will the change in enzymes affect their reactions with the protein. Since the canned pineapples have been heated, it will affect the enzyme activities by turning off its active sites. Because of the closed active sites, the substrates will not be able to enter enzymes for reaction. Therefore, the Jell-O would not react with inactive enzymes in canned pineapples, and eventually becomes solid. 

 INTRODUCTION
  The role of enzymes in the digestive system is to accelerate the reactions of substrates and lower the active energy barrier. To achieve that, the enzymes allow the substrate into its active sites. The active sites of the enzymes will act as a template for substrate orientation, stabilize the transition state of the substrates, provide a favorable micro-environment, and directly participate in the catalytic reaction. In the specific situation between pineapples and Jell-Os, the proteases in bromelain, which is a chemical in the pineapple, will break the collagen bonds in Jell-O, and stop the Jell-O from forming a solid state. (Source) However, do different conditions of pineapples affect the resulting form of the Jell-O?

 HYPOTHESIS
  We hypothesized that the Jell-O with canned pineapples and the Jell-O without pineapples will change their states to solid, while the Jell-O with fresh pineapples remains liquid. 

The box cover of Jell-O with instructions

 MATERIALS
1. 3 empty petri dishes
2. A water beaker
3. Strawberry-flavored Jell-O powder (6.6 grams)
4. Canned and fresh pineapples, and each type has 6 pieces in the same size (26 grams for each type)
5. A boiling plate
6. 78.8 ml of water
7. Tapes and markers
8. A stirring stick

 PROCEDURE
 We began the lab by making strawberry-flavored Jell-O:
   At first, we heated 39.4 ml water by using the boiling plate, and we put 6.6 grams Jell-O powder in the beaker. Then we poured the boiling water into the beaker, and we stirred the water with the powder until the powder is completely dissolved. Later, we added another 39.4 ml cold water to the jello, and stirred the jello mix again until the water is fully mixed. 
  After we finished making the Jell-O mix, we put the mix in 3 petri dishes, and each dish should have the same amount of Jell-O. To finish the process, we put 26 grams of fresh pineapples, the independent variable, in one dish, and 26 grams of canned pineapples in another one. We put our names on the petri dishes with tapes and markers, and we kept them in the room for two days until we return to check the result. 

Results of our lab

RESULT
  As a result, the Jell-O dish without pineapples and the Jell-O with canned pineapples have both changed to a solid state. However, the Jell-O dish with fresh pineapples is still in liquid state.

CONCLUSION
  The result of our lab proved our hypothesis correct. The Jell-O with fresh pineapples didn't become solid because the collagen bond in Jell-O or other gelatins will be broken by going the reaction process with digestive enzymes in pineapples. Since the room temperature is comfortable for the pineapple enzymes, the collagen can easily enter the active site and react with them. However, we could have achieved more in this lab by using different fruits or different temperature, and a possible error in the lab would be the limited time to wait for the jell-O to form before we check the result. 

WORKS CITED
  Helmenstine, Anne Marie, Ph.D. "Pineapple and Jell-O." About.com Chemistry. N.p., n.d. Web. 17 Feb.   2014.

Answers for Forensics Take-Home Quiz

  The most plausible death cause of the victim would be heavy blood loss as a result of an accidental murder of an animal hunter. The bullet wound of the victim began from the left lateral side 1cm above the 3rd rib in a 45-degree downward angle, and ended 5 cm above the belly button in umbilical region of abdomen. Also, the 8th rib on the right side was fractured. The trail of the bullet travels through the liver and possibly the stomach. Since the liver plays a major role in metabolism, and is in charge of decomposition of red blood cells and detoxification. Therefore, the punctured liver would stop working, thus the metabolism of the body would stop and the red blood cells would not be decomposed or detoxificated and eventually escape from the body. Also, the escaping enzymes and strong acids in the punctured stomach would decompose tissues and organs, and harm other systems in the victim's body.

  Other plausible causes of the death would be:
1. Physical conflict, because there is bullet wound in victim's body, which may result from an argument. However, this possibility is eliminated because there is no sign of struggle from the victim, nor bruises as results of fighting. Also, the unusual 45-degree angle of bullet trail increases the doubt of the possibility of intentional murder as well.
2. Suicide, because the bullet trail began from the front of the victim's body. However, the possibility is eliminated as well because of the unusual 45-degree downward angle, and the absence of the gun near the victim's body.
3. Animal Attack. This possibility is eliminated because no superficial cut or bruise is found on the victim's body.

Weekly Update: Last Class of Cancer!

     Today we shared our research results of the question about stem cells we picked on the class blog. Carrissa, Lucy and I worked on one of my questions posted about Michael Bay's film The Island, which is whether the organs needed for transplant can be bred independently without building an entire clone. Our answers show that it is possible, but very difficult as well, since the organs in human body can barely survive without a supporting system.
     Human organ transplant has been a very critical issue recently, because the demand is always larger than the supply. The supply of organs was completely based on donations of the deceased, and it is dependent on the number of people willing to donate organs and whether it will match with the recipients' bodies.

     

     The scientists are developing 3 approaches to solve this problem. The first approach would be therapeutic cloning. This technology specifically deals with stem cells in human body. The adult stem cells can be converted to pluripotent stem cells which can transform to any type of cells in body. However, this carries a huge risk as well, because the recipient will have a higher chance to get cancer, because the new stem cells are more susceptible to proto-oncogene mutations.
     The second approach scientists are currently developing is xenoplantation, which means transplanting animal organs. Particularly, the scientists are looking at transplanting pig organs to human body due to their similar organ structures and sizes. Early attempts of this development can be traced back to late 1990s. However, the early experiments failed because the recipient's body recognized pig organ as a foreign tissue and attacked the organ. Therefore, the scientists will modify the pig genetically in their embryonic period, by adding 6 human genes in their stem cells to regulate the response from the recipient. However, this technology are considered unethical, and thus its application will be very limited.

     The final approach is the latest 3-D printing technology. Currently, researchers are printing mini organ systems in order to test the responses of new drugs from human body. The ultimate goal is to build a fully functional organ that would address the issue of the gap between organ supplies and demands.
     For the assignment today, I watched a Ted Talk video about new organ growth with new biotechnology. If the organs needed is small, it can be regenerated with smart biomaterials. The smart biomaterials served as the bridge in the gap of wounded organ (urethra), and the wound can be healed after the body regenerates itself to connect both ends of the bridges. Since the body can only regenerate in a very limited distance (around 1cm), a larger injured organ can be difficult for transplant. The technology requires a small part from the injured tissue, take the cells out, and let them grow and expand outside the body before the scaffold material is applied to take the cells back into the body. If a solid organ is injured, the methods of 3-D printing and de-cellularized organs can both be useful. The decellularized organs are skeletons of the organs that carry no cell elements. Later on, we can inject the cells of the patient to the new liver, and let them expand and grow to fully functional organs.

- Andy Liu '15

Ethical and scientific questions about "The Island"

                 

1. Ethics: After the clones are released from their habitat, how will they adapt to the human society? Particularly, what identities should they have when there are still real humans that have the same physical traits as them? How should the government deal with the clones if they began to steal those people's identities?

2. Science: Since clones can develop their own emotions and intelligence, which can be a threat to the human society, while the humans only need some healthy organs of the clones, is there any way the scientists can breed the required organs only? 

Comment on "Your Inner Healers"

  The article I read for the assignment involves a new type of biotechnology and the enormous potential that comes with it. A group of Japanese scientists discovered a formula for creating induced pluripotent stem cells from adult cells with only four necessary genes and without eggs or embryos. By dedifferentiating (reverting back to a more primitive type) the adult stem cells, we can discover the source of many diseases that we fail to cure today, and find new ways of therapy.
  However, I don't believe that the technology considered as the modern "Fountain of Youth" is ethical. The entire idea of evolution and natural selection discovered by Charles Darwin was based on survival of the fittest. Species adapt to different environments by mutations, and the group that cannot survive becomes extinct. This has always been the rule of the jungle as we know it, and defying that rule will not make us God or Mother Nature itself. When this type of technology applies to everyone in the world, when everyone can live as long as they want, and when all humans stops producing new generations due to overpopulation, will the technology make us the saviors of mankind, or the destroyers of the world?

- Andy Liu '15