Unit 4: Cell Communication

Following up from last unit, cell communication is another important part of biology. Cells communicate with each other in a variety, ranging from the endocrine system to the nervous system.

From this unit, I was able to effectively learn about the various forms of cell communication. Cells in the body typically communicate with chemical signals. However, the many external signals are taken in from the body, and are then sent to the brain via electrical impulses. Neurons send these signals to the brain.

In this unit, I was able to effectively apply science practice 1. Drawing and modeling neurons, the brain, and how drugs affect the brain was important. Through computer generated models, I was able to learn how the different drugs affect the brain and was able to replicate them. Furthermore, I was able to replicate and model the endocrine system and how a neuron fires.

In this unit, I had trouble recognizing and remembering the different parts of the body and the different glands that produced chemicals. I think that part of this was because I put particular focus on learning the systems themselves instead of the actual human organs that were responsible for them. However, I think that this can be corrected by focusing on these organs in future units and possibly just through constant exposure to them. As Unit 11 is "Animal Structure and Function", I believe that we will go back over them again, so I will review the different glands then.

AP Science Practices 

• SP1:The student can use representations and models to communicate scientific phenomena and solve scientific problems.
• SP2: The student can use mathematics appropriately.
• SP3: The student can engage in scientific questioning to extend thinking or to guide investigations within the context of the AP course.
• SP4: The student can plan and implement data collection strategies appropriate to a particular scientific question.
• SP5: The student can perform data analysis and evaluation of evidence.
• SP6: The student can work with scientific explanations and theories.
• SP7: The student is able to connect and relate knowledge across various scales, concepts and representations in and across domains.

• Organisms use feedback mechanisms to maintain internal environments and to respond to changes in the external environment.
• Cell communication pathways enable cell-cell communication and reflect a common ancestry.
• Signal transduction pathways link environmental changes and stimuli to cellular responses.
• Animals have a nervous system that respond to stimuli .

Unit 3: Cell Structure, Function & Transport

The learning outcomes for this unit is cell oriented. Cells are the most basic unit of life, and have obvious important implications for the rest of biology, especially in the human systems that we study (nervous, endocrine, and immune systems). 

I feel that I was able to fulfill science practice #4 in this unit via the osmosis/diffusion lab. This lab empirically taught me how water diffused between cells by moving from an area of lower concentration gradient to one of a higher consternation gradient. This is why drinking salt water harms you; it the salt in the water can't enter the cells, so it creates a higher concentration gradient on the outside of the cell, which actually forces the water to leave the cell, thus making a person more thirsty. 

I additionally was able to apply SP7. Unit 1 was about evolution, and how different creatures and bacteria evolved into what they are today. The Endosymbiotic cell theory is the theory that the mitochondria was actually a prokaryote that for some reason or another entered a modern eukaryote and helped it. This gave it an advantage, and the characteristic spread until eventually it spread to the extent that it has today.

• All organism require a constant input of free energy which is stored and used to grow, reproduce, and maintain organization.
• Cell membranes create different environments across which some molecules will move to maintain homeostasis and respond to environmental changes.
• Internal membranes create specialized regions within the cell.

AP Science Practices

• SP1:The student can use representations and models to communicate scientific phenomena and solve scientific problems.
• SP2: The student can use mathematics appropriately.
• SP3: The student can engage in scientific questioning to extend thinking or to guide investigations within the context of the AP course.
• SP4: The student can plan and implement data collection strategies appropriate to a particular scientific question.
• SP5: The student can perform data analysis and evaluation of evidence.
• SP6: The student can work with scientific explanations and theories.
• SP7: The student is able to connect and relate knowledge across various scales, concepts and representations in and across domains.

Unit 2: Biochemistry

Biology is considered to be one of the applied sciences. An applied science is different from a pure science because an applied science involves other fields. For example, you can't understand Biology without knowing chemistry. Molecular shape plays an important part in biology, ranging from the different molecules and their effects to the specific molecular shape of the substrate that allows it to bind to the enzyme. This unit means to cover the chemistry needed to effectively understand Biology.

One thing that I felt that I understood well is the process of protein and the creation of proteins. Protein folding involves 4 steps, primary, secondary, tertiary, and quatinary. Primary is ordering the individual molecules that will make up the protein, secondary involves alpha and beta folding of the protein, tertiary involves the creation of disulfide bridges, and quatinary involves connecting the folded protein to other proteins. The protein only becomes functional after the final step.

Something that I felt that I needed to improve on was my ability to know the different side groups. The side groups are very different, and even side groups that sound very similar (Carbonyl and Carboxyl groups) have very different functions. In this case, the Carboxyl group helps create an acid (chemical formula -COOH) and the Carbonyl group (-CO-), (-CO) changes function and creates isomers depending on where it is located within the molecule.

AP Science Practices

• SP1:The student can use representations and models to communicate scientific phenomena and solve scientific problems.
• SP2: The student can use mathematics appropriately.
• SP3: The student can engage in scientific questioning to extend thinking or to guide investigations within the context of the AP course.
• SP4: The student can plan and implement data collection strategies appropriate to a particular scientific question.
• SP5: The student can perform data analysis and evaluation of evidence.
• SP6: The student can work with scientific explanations and theories.
• SP7: The student is able to connect and relate knowledge across various scales, concepts and representations in and across domains.

• The subcomponents of biological molecules and their sequences determine the properties of that molecule.
• Interactions between molecules affect their structure and function.
• Cooperative interactions within organisms promote efficiency in the use of energy and matter.
• Variation in molecular units provides cells with a wider range of functions.

Unit 1 Wrap Up- Evolution

Unit one is an important building block for Biology. So far, we have referenced evolution in every unit so far, ranging from cell chemistry to the endosymbiotic theory.

In unit 1, we were able to employ SP1. We employed SP1 when using the Hardy-Weinberg equilibrium, which models an unchanging hypothesis. Hardy-Weinberg equilibrium is meant to serve as a null hypothesis, because if you can prove that the Hardy-Weinberg equation isn't true, then evolution is happening in a population, and helps serve as a model for evolution. Another model invented by the same scientists is the idea of the Hardy-Weinberg equation, which is used to calculate the genotype/phenotype frequencies in a population that isn't evolving.  This also works with SP2, which is using mathematics appropriately. I initially had trouble using the H-W equation, but was able to eventually lean how to use it by the end of unit 1. 

I plan on continuing to apply the principles of evolution to other topics in AP Biology, and hope that this unit will be helpful in my future study.

Unit Objectives

• Change in the genetic makeup of a population over time is evolution.
• Organisms are linked by lines of descent from common ancestry.
• Life continues to evolve within a changing environment.
• The origin of living systems is explained by natural processes.
• Timing and coordination of behavior are regulated by various mechanisms and are important in natural selection
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Science Practices

• SP1:The student can use representations and models to communicate scientific phenomena and solve scientific problems.
• SP2: The student can use mathematics appropriately.
• SP3: The student can engage in scientific questioning to extend thinking or to guide investigations within the context of the AP course.
• SP4: The student can plan and implement data collection strategies appropriate to a particular scientific question.
• SP5: The student can perform data analysis and evaluation of evidence.
• SP6: The student can work with scientific explanations and theories.
• SP7: The student is able to connect and relate knowledge across various scales, concepts and representations in and across domains.

1st Quarter Reflection

I thought that the unit on evolution went well. What surprised me about tis unit was that Darwin's theory of evolution was slightly different than the modern theory of evolution. I had always thought that the theory of evolution hadn't changed after Darwin's idea, but that turned out to not be the case.

I found the chemistry unit to be difficult. Specifically, I found memorizing the shapes of the molecules and all of the different molecules and the R-groups and how they changed each molecule. Since chemistry is important throughout all of biology, it is important for me to go back through the chemistry chapter and review chemistry. I also have had trouble with my handwriting, which has become sloppy.

One way for me to improve my handwriting is to write less for the free response. By writing less, I can be more concise and to the point. I can also focus on making my handwriting more legible during the test. I've found that if I write slower, then my handwriting is more readable. To improve how I feel about the chemistry unit, I plan on going back and rereading over the chapter, and trying to memorize more of the R-groups.

I am looking forward to learning more about neuroscience. The brain is very complicated, but since we are just scratching the surface of the brain and our nervous system, it isn't exceptionally difficult (compared to the other units). Other than that, I am looking forward to seeing how evolution affects the rest of biology!

The coolest thing about Biology

The coolest thing about is the endosymbiosis theory. The endosymbiosis theory is the idea that the mitochondria was originally another another cell. This cell then moved into the cell membrane of one cell for a unknown reason, and this formed a symbiotic relationship. Both cells benefited, and eventually they both coevolved with each other until one became part of the other. This also applies some other organelles, such as chloroplasts in plants! Below is a diagram that shows how endosymbiosis happened.


Image Source:

Endosymbiotic Theory. (2013, August 11). Wikipedia. Retrieved November 1, 2013, from http://en.wikipedia.org/wiki/Endosymbiotic_theory