Unit 3 Reflection

In this unit we learned about the cell theory, activation energy, membranes, osmosis and diffusion, what a cell does, photosynthesis, and cellular respiration, The most challenging thing about this unit is cellular respiration. There are three steps to cellular respiration. The first step to it is glycoolysis which occurs in the cytoplasm. 2 ATP molecules are produced for one glucose molecule in this step. The second step is the Krebs cycle which converts molecules from glycolysis into 2 ATP, carbon dioxide, and electron carrying molecules. The final step is the electron transport chain which occurs within the inner membrane of mitochondria. It uses oxygen, NADH, and FADH2 to convert ADP into ATP. 32 ATP is produced in this step. This whole process produces a total of 36 ATP, 6 carbon dioxide, and 6 water. Cellular respiration is the process of cells braking down glucose into energy. Photosynthesis is where plants produce glucose and oxygen using sunlight and carbon dioxide. Autotrophs carry out photosynthesis and can be macroscopic or microscopic. They can be multicellular of unicellular. Mesophyll cells are a collection of cells containing chloroplasts. A chloroplast is an organelle containing stroma and grana. Stroma is the space inside chloroplasts and grana is a stack of thylakoids. Thylakoids are membranes that contain chlorophyll. A light dependent reaction occurs in thylakoids of grana. Light is absorbed and energy is transferred between molecules by the electron transport chain. It produces NADPH and ATP. Water is split which releases oxygen and pumping H+ ions into the thylakoid membrane. ATP synthase uses H+ movement to produce ATP. ATP synthase facilitates diffusioin of H+ from high to low concentration. As H+ moves from thylakoid to stroma, ATP is produced. In a light independent reaction, it produces sugar from carbon dioxide using ATP and NADPH from light reactions. The calvin cycle rotates 6 times to produce 1 glucose molecule. I learned a lot from this unit but there is still a lot to learn about biology. I learned a lot about cellular respiration and how photosynthesis works.

Egg Diffusion Lab

Our question was how and why does a cell's internal environment change, as it's external environment changes? We two eggs in vinegar and let it sit for two days. We then washed off the vinegar and put it in water instead. Adding the vinegar go ride of the egg membrane which exposed the rest of the egg. We then put one egg in water and another egg in sugar water. 

When we put the sugar concentration increased, the egg shrank. It shrank because there was a high concentration of sugar and a low concentration of sugar so the water in the egg diffused outside instead. For the one in water, in grew because there was more solute inside than outside so the solvent went inside the egg and the egg grew. This was a hypertonic diffusion. 

A cell's internal environment changes as the external environment changes because of diffusion. There was a low concentration of sugar in the deonized water so there was actually more solute in the egg than in the solvent. The one with sugar water was hypertonic because there was a higher concentration of sugar in the solvent, causing the egg to shrink. So the water diffused from inside the egg to the outside. These were all examples of passive diffusion.

 This lab demonstrates the biological principle of diffusion. It shows how diffusion works within cells.

Fresh vegetables are sprinkled with water at markets to keep them fresh. It is the make sure the vegetables don't lose too much water and dry up. Roads are salted to melt ice because it requires an even lower temperature to freeze ice so putting salt on the ice will help melt it. Too much salt can dehydrate plants. Salt absorbs moisture in water. 

If you were to create a new experiment you would want to test how different concentrations effect cells.  

Cure for Cancer?

One of the big questions of science is "Will there ever be a cure for cancer?" The current hypothesis is that if cancer is a living thing, then there will never be a cure for cancer. We can prevent and treat it, but there is no definite cure for cancer. The longer we live the more likely something will go wrong. Cancer has been around since dinosaurs and it is still here.

20 Big Questions:
1. Will there ever be an end to learning?
2. Why are there different skin colors?
3. What is the meaning of life?
4. Why is the sky blue?
5. Why don't we have a tail?
6. Will there ever be an end to sickness?
7. Why is grass green?
8. Why don't plants grow faster?
9. Is it possible to never get sick?
10. How did people know about sugar?
11. Who was the first to start baking?
12. Why are some people smarter than others?
13. Why do we have hair?
14. How do computers work?
15. Who invented mechanical pencils?
16. Why are all our tastes different?
17. Is it possible to make a new color?
18. Who invented the first shoes?
19. Who invented glasses?
20. Who invented hair ties?

Egg Macromolecules Lab Conclusion

The question for this egg macromolecules lab is "Can macromolecules be identified in an egg cell?" Macromolecules can be identified in egg cells. Polysaccharides can be found in the egg membrane. For egg white a tiny bit of protein can be found. Monosacccharides can be found in egg yolks. For polysaccharides we did a test using iodine. The color should change from brown to black if a polysaccharide was present. In the egg membrane it turned dark brown and and its quantitative amount was 7. For monosaccharides we used benedicts solution which would have turned green or orange if there was a monosaccharide present. It was present in the egg yolk with a quantitative amount of 6. Lastly, in egg white, proteins were found. Although there was an error in protein because we didn't mix properly, there was a slight sign of protein. We used sodium hydroxide and copper sulfate to test for proteins. It should have turned from blue to purple. One big error we made was the testing for proteins. Almost none of them were positive. This was because we didn't mix the sodium hydroxide and copper sulfate enough. Another possible error we made was measuring. We might not have measured properly which would be another reason why it didn't test positive for some of the other macromolecules. To improve this experiment, it would be better to mix the sodium hydroxide and copper sulfate a bit better. Another thing would be to measure more accurately. The purpose of this lab was to find which macromolecules go in which part of the cell. This relates to us learning about macromolecules and cells in class. This can be applied for future studies on biology. We now know what macromolecules go in what part of a cell.