Unit 3 Reflection

In unit 3, we learned about the cell and all its processes and many intricacies. We learned about the complexity of organelles and how our energy is collected. Although a wide variety of topics were covered, they all shared a common theme: the cell. I think that most of the unit was quite easy, because some of it was just a review of 7th grade biology. I even knew a little in depth information about photosynthesis and cellular respiration before learning this unit. But if one thing is the hardest to grasp in this unit, it would be cellular respiration. I think this is because it has 3 sort of overlapping parts rather than photosynthesis' 2 distinct parts. Even after watching the vodcast, I was still not completely sure about where reactants went in and products came out.

One thing that definitely helped is drawing a diagram. By illustrating the 3 pieces of CR separately and with clean sketches, I was able to understand where and why certain reactants entered CR. This taught me the important skill of drawing diagrams. A diagram is not something that would help only in biology; it could also be applied to chemistry, physics, and a variety of other topics. I do think that I'm a better student now than at the start of this unit. I have learned important studying skills as well as gained a better understanding of the way a cell works. I want to learn more about photosynthesis and cellular respiration. How exactly does ATP synthase work? What are the "in between" steps of the reactions that weren't taught in class? To study for this test, I will probably not make flash cards because I feel like I have already mastered the concept of organelles. However, I will definitely draw out the reactions of photosynthesis and 3 parts of cellular respiration. This process will help me tackle the exact processes and give me a deeper understanding on the topic.

Egg Diffusion Lab Conclusion & Analysis

In the egg diffusion lab, we took 2 eggs and placed them in 2 liquids for a few days: deionized water and corn syrup. We hypothesized that the egg in the deionized water would expand and that the egg in the corn syrup would shrink.

When the concentration of sugar (solute) in the external solution was high, water (solvent) left the egg to maintain the proportion of water to sugar. This caused the mass and circumference to decrease. This is proved by the fact that most of the groups' eggs in corn syrup decreased in mass by around 45%, which is a large difference. The change in circumference also hovered around -21%.

A cells internal environment changes depending on its external environment through a process known as "diffusion". Diffusion always moves molecules from areas of high concentration to low concentration. For example, if a large amount of water is outside of the cell, the water will enter the cell until both sides of the membrane have around the same water concentration. However, if a solute like the sugar in corn syrup is unable to pass through the membrane, then water diffuses out of the cell until the ratio of water to sugar is the same on both sides of the cell membrane.

This lab demonstrates the biological principle of diffusion. Diffusion is extremely important to cells and allows for water and nutrients to move in and out of the cell without the use of energy. By putting an egg, essentially a cell, in a hypertonic solution we investigated the effects solute concentration had on a cell.

Fresh vegetables may be sprinkled with water to counteract the natural process of water leaving the plant cells due to diffusion. If water is sprinkled on the vegetables, the concentration gradient would be less steep which would decrease the rate at which water escapes vegetable cells. This helps prevent the vegetables from wilting or becoming squishy. Salting definitely has a detrimental effect on roadside plants. When salt approaches the roots of a plant, it creates a gradient that forces water out of the root cells. This causes the plant to wilt and may eventually result in its death.

After understanding the results of this experiment, I would like to test what would happen if I removed some of the egg white from another egg and injected it with a hypertonic sugar fluid. This egg would then be placed in a beaker of deionized water. I hypothesize that this egg would absorb water until it bursts. If this hypothesis is correct, it would prove that the membrane is semipermeable from both sides.

Egg Cell Macromolecules Conclusion & Analysis

What macromolecules are present in the cell and where are they?

     The membrane contains polysaccharides. When we put the membrane in an iodine solution to test for polysaccharides, it turned black. The membrane contains this because it uses polysaccharides to communicate with other cells. The egg white had proteins floating around in it. We know this because when the separated egg white was dropped in copper sulfate, a chemical that tests for peptide bonds, the solution turned purplish. The egg white may contain proteins for helping the developing chicken embryo grow. The proteins would provide nourishment and vital ingredients for life.The egg yolk was composed of lipids. This was learned when the broken down yolk was put in a solution of Sudan IV. Soon, it turned a shade of orange. The yolk probably contains lipids because it is actually a cell. Cells have phospholipid membranes, so this is the most likely reason for a positive lipid test.

     One possible error is that a sample was contaminated. If one sample was accidentally mixed with the one being tested, it may show positive results when in reality the macromolecule is only present in the contaminant. If this happened, then the macromolecules that the evidence proved may not normally be present. Another mistake that could have occurred is if an inadequate amount of testing substance was used. In the procedure, it only said how many drops should be added. This is not a very accurate measurement and people may have also miscounted the amount of drops of a chemical they added. This may cause no results to be displayed even when a part of the cell contains a certain macromolecule. These inaccuracies can be remedied in the future by assigning each table a certain part of the egg rather than having each group test every single part of the egg. This new procedure would reduce the chance of contamination. The amount of testing chemical should also be changed from "drops" to "milliliters". This is a more standard and widely accepted measurement unit and would help prevent not using enough testing solution.

     The purpose of this lab was to learn about the function and location of macromolecules in the cell. This relates to an activity I did in seventh grade where we made a chart of the macromolecules and wrote facts about what they did and where in the cell they are found. What I learned in this lab can be applied to situations where I may need to retrieve a certain macromolecule from the cell. With this information, it will be easier to know where the molecule is and how to isolate it.


Monosaccharide Test tubes- From the left: water, membrane, white, yolk

Inquiry Hour 1.1: Identifying Questions and Hypotheses

The question was, "Do monkeys and humans perceive optical illusions in the same way?". The hypothesis was that the monkeys would perceive the pictures as illusions. This is because in a similar study executed previously, the tested monkeys saw perceived the size of circles incorrectly: a purpose of the optical illusion.

The study used a type of illusion called a Delboeuf illusion. These consist of a thin circle with a large filled in dot in the center. The size of the center dots stay the same, but the thin surrounding circle's size changes. This creates the illusion that dots in smaller circles are larger than dots in bigger circles. To test whether the monkeys saw the images as an illusion, the researchers trained monkeys to use joysticks and computer monitors. Both the monkeys and humans were asked to classify dots as large or small. When they answered correctly, humans were given a written reward and monkeys were given a banana flavored pellet.

http://www.sciencedaily.com/releases/2015/09/150928083116.htm

"What is consciousness?", and another 20 Questions

I really like most all of the questions in the article, especially the first few near the top. But if I had to choose one, I'd say my favorite question is, "What is consciousness?". I think this question appeals to me because we hardly know anything about our brain and nervous system. And even though we know all about the physiological processes, we are nowhere close to comprehending our ability to understand language and picturing images in our mind.
The consciousness is one of these mysterious things about the brain that I don't think anyone really understands. In reality, our body is just a means of receiving and exporting information. The brain is the real thing controlling, preparing and processing this information.
I also believe that our understanding of "what we are" has changed over time. Originally, we assumed that this body was "me", and later we were able to grasp the concept that we are actually just a lump of neurons sitting in this body's head. Soon, I think we may be able to fully comprehend the fact that our consciousness is just a bunch electrochemical messages constantly being relayed between a few billion neurons inside of our skull.
The main hypothesis on what our consciousness is, is that as we sift through so much information in our lifetime, we quickly are able to tell what is real and what is not. We learn that the things we imagine and dream are all in our mind, but the real world is something that others also perceive and that everyone knows is true.
My Big 20 Questions: 

1. What causes self-awareness?
2. Do we have biological free will from our brains?
3. What allows us to see things in our mind? What allows the mind's eye?
4. Is medical progress hindering human evolution?
5. Why are plant cells usually larger than animal cells?
6. How much energy does my phone use per minute?
7. Who will win the 2016 presidential election?
8. Because our government uses the electoral college, is the USA really a democracy?
9. How can I know that the universe didn't begin just a few minutes ago and that all my memories were implanted?
10. Is Obama and any of our federal government real? I've only seen them on TV.
11. How much longer will we continue to find and use fossil fuels?
12. Is solar power ever going to become practical?
13. When will the human race master interstellar space travel?
14. Will socialism ever become the global government norm?
15. Will humans slowly degrade mentally and physically due to our laziness and stupidity?
16. Will humans ever become a purely mental race which only interacts psychologically rather than physically?
17. If time travel is possible, then where are the visitors hiding?
18. Why does my ring finger also bend when I bend my pinky?
19. Could humans function with only 2 or 3 fingers and an opposable thumb?
20. Can gravity truly be quantized and if so will we be able to harness its potential as an energy source?

Unit 2 Reflection

The general purpose of this unit was to understand the chemistry involved in biology. Themes included understanding basic atomic structure, intermolecular forces, macromolecules, and how enzymes worked. I think I was able to understand everything in this chapter and some of my favorite parts included the macromolecules and how enzymes function. However, one part I didn't find too interesting was the pH scale. This is because I've already learned about it many times for various reasons, and some of the information seemed inaccurate.
In this unit I learned about how atoms form bonds, how biological systems use enzymes to do their work, and what causes the meniscus in a graduated cylinder. One skill I learned in this chapter was how to use data tables to make graphs in google sheets.
I think I am a better student now than at the start of this chapter, because although I knew a large portion of the content I didn't fully understand how they worked. I also wasn't aware of the extremely intricate structure of enzymes. I would like to learn more about enzymes and proteins. This is because proteins and enzymes are like microscopic biological machines that have a large potential for scientific use.

Cheese Lab Conclusion

What are the optimal conditions and curdling agents for making cheese?

CER: The best curdling agent to use is Chymosin in a hot, acidic environment. In the lab, Chymosin curdled the milk in 5 out of the 6 conditions. This shows that the milk may continue to curdle even if something happens to the machine that keeps the enzyme’s environment in check. The environment should be hot because in the lab, the hot environment produced curdling in 5 minutes for Chymosin. Also, the environment should be acidic because during testing, chymosin produced curds in 5 minutes when it was in an acid. If hot and acidic make the enzyme produce curds faster, then a hot and acidic environment would be best from a manufacturing perspective because cheese could be produced very fast.

Possible Errors: Some possible errors may result from different people’s armpits, and accidents during timing the incubation. The temperature of the underarm varies slightly from person to person and some groups didn’t even put the test tube in their armpit. The effect of this may be that the enzymes in some tubes may have been more active than others and would eventually result in inconsistencies in the time for curdling. When I ended the the 10 minute timer for one of the incubation rounds, I forgot to immediately restart it. This means that the timing of that round was slightly off. If everyone made small mistakes like these, then overall it could create a large timing difference which would skew the results. To prevent inaccuracies in time from occurring, I would alter the procedure of this experiment in 2 ways. One thing I would do is put all of the test tubes in an incubator with a steady temperature to prevent differences from underarm to underarm. Another thing I would change is the way we time. I think that the timer should run for 10 minutes, then have a 10 second pause to check for curds, and then restart its 10 minute cycle. This would prevent the humans from forgetting to restart the timer.

Practical Applications: The purpose of this experiment was to understand how different factors such as pH and temperature can affect the activity of enzymes. This relates to what I’ve learned in class because in 8th grade we learned about pH and hydronium ion concentration. This makes me think about why and how hydronium can affect enzymes. The results of this lab could be applied to making cheese at home. I have already made cheese at home many times, but only used buttermilk. Now I know that if I want the quickest outcome, I could purchase some chymosin or rennin.

	Chymosin	Rennin	Buttermilk	Milk (Control)
Acid	5	5	5
Base	20
pH Control	15	10
Cold
Hot	5	5
temp. Control	10	10