Floating Leaf Disk Lab

Purpose: To test the effects of the concentration of baking soda on the rate of photosynthesis

Background: Leaves go through the process of photosynthesis to produce sugar (C₆H₁₂O₆) and oxygen (O₂) using carbon dioxide (CO₂), water (H₂O), and a source of light. Leaves have multiple layers and the central layer is called the spongy mesophyll because there is air between the cells giving a sponge-like an appearance. These air gaps can be filled with a solution if the liquid is forced in. This would change the density, causing the leaves to sink in the solution. In the correct conditions, photosynthesis can occur and the leaves will be able to float, as a result of the O₂ produced. The rate of photosynthesis can be measured based on the number of leaves floating because the oxygen that is produced by photosynthesis causes that to happen.

Data: Overall, the rate of photosynthesis in the spinach leaves decreased and the time taken for the leaves to float increased. as the concentration of baking soda increased. 3 different concentrations of baking soda were tested: ¼ tsp as the control, ½ tsp, and 1 tsp. Fewer leaves floating in the ½ tsp baking soda solution (5 leaves) compared to the control (8 leaves), and even less floated in the 1tsp baking soda solution (4 leaves).

Questions

1. Explain the process of carbon fixation.

Carbon fixation is the first step in the Calvin Cycle that incorporates CO₂ into organic molecules. RuBisCo, an enzyme in plants, attaches the carbon to the sugars. This helps produce glucose.

2. Explain the process that causes the leaf discs to rise.

The baking soda that is added into water breaks up and produces CO₂. A light is shined activating photosynthesis. The light separates water into H+ and O₂ and the oxygen fills up the air in the spongy mesophyll layer in the leaves. The leaf discs float when enough oxygen is made to lift their masses.

3. What is the effect of darkness on photosynthesis? Explain.

Darkness will stop the light-dependent reactions that convert light energy into chemical energy. The light-dependent reactions are the first step in photosynthesis. Without the products from the light-dependent reaction (ATP and NADPH), the light-independent reaction cannot occur so the process of photosynthesis will not be completed and no more O₂ will be produced. In this lab, the leaf discs could only float once O₂ is produced, so in darkness, the leaves will be unable to float. 

4. If we were to boil the leaf discs, what kind of results would you expect? Why?

Boiling the leaf discs would stop them from floating. The drastic temperature increase would denature enzymes so the process of photosynthesis would not occur. Since photosynthesis cannot occur, O₂ cannot be produced and the leaves will continue to sink. 

5. How would light intensity affect the rate of photosynthesis?

Light intensity would increase the rate until a certain intensity. After that is reached, the rate will decrease as the intensity continues to increase. This is because there is an optimal amount of light that is ideal for photosynthesis. The rate of photosynthesis is highest when the optimal light intensity is shined on the plant. 

6. How does the light intensity and the rate of photosynthesis relate to the position of the sun, both, during the day and during the year?

The sun changes the position in the sky during the day and during the year. Photosynthesis is most efficient during the daytime and in spring and summer, when the sun is out and when the light intensity is the highest. Though photosynthesis still occurs in fall and winter, the rate is slower so leaves cannot produce enough C₆H₁₂O₆ to survive. That is why leaves turn brown during the winter season and some fall off the trees. The rate of photosynthesis is faster in spring when the sunlight is bright but not too intense. The sun is too intense in the summer, but not intense enough in fall and winter so the rate of photosynthesis is slower.

Chromatography with Different Colored Leaves

Purpose: To separate and identify pigments from green and non – green leaves using chromatography

Background: Chromatography is a process that separates a mixture into the various pigments, and this process is also used to identify various colors. A pigment is the natural coloring in organisms, that absorb certain wavelengths of light and reflect others. The colors that are reflected are the ones that are seen. A strip of chromatography paper with dye is placed into a solvent. The soluble pigments travel up the paper producing different colored streaks by capillary action, which is the tendency of a liquid to move up the material. The rate of migration of the pigments and the distance of the colored bands is based on the solubility of the solute in the solvent, the mass of the sample, the diffusion from a high concentration of solvent to a low concentration of pigment going against gravity. The diffusion depends on the sample’s attraction to the paper which will cause the sample to move up the paper but if the substances are attracted to each other, they will stop moving. Rf is the ratio between the distance the pigment traveled and the distance to the solvent traveled. Rf is the same for the same pigment under the same set of conditions (same paper, same solvent, etc.) so this ratio is used to identify certain pigments.

Hypothesis: If the pigments identified in the non- green leaf are red, purple, and green; then a band will appear for each color. If the pigments identified in the green leaf are green; then a green color band will appear on the paper.

Data:

Green Leaf

	D unknown (cm)	D solvent (cm)	Rf
Red	None	None	None
Yellow	None	None	None
Light Green	6.0	6.8	0.88
Green	None	None	None

Non – Green Leaf

	D unknown (cm)	D solvent (cm)	Rf
Red	3.6	9.7	0.37
Yellow	2.5	9.7	0.26
Light Green	None	None	None
Green	None	None	None

Questions:

      1. What is the basic importance of chromatography?

Chromatography is a process that is useful to separate the various pigments that make up one sample and identify these colors using the Rf values.

2. What factors allow chromatography to happen?

Capillary action, diffusion, the mass of the solute, and the solubility of the solute in the solvent all allow chromatography to happen.

3. What purpose does the chromatography paper have in this experiment?

Chromatography paper is present to facilitate chromatography and provide a medium for the solute to move up and create a pattern.

      4. What is the purpose of the solvent?

The purpose of the solvent is to help move the sample up the paper so that the pigments can be separated.

5. What does Rf value stand for?

Rf is the ratio between  D unknown and D solvent.

     6. How do you think that the Rf value is useful to scientists?

Rf is used to identify pigments because a pigment will have the same Rf value in the same conditions.

     7. What does Dunknown signify?

Dunknown is the distance the pigment travels from the location of the original mark in centimeters.

      8. What does D solvent signify?

D solvent is the distance of the solute travels from the location of the original mark in centimeters.

      9. How many pigments were you able to identify from the GREEN leaf chromatogram?

The green leaf had one pigment which was light green, as the image below shows.

      10. How did a GREEN leaf chromatogram compare to a NON-GREEN leaf chromatogram?

The green leaf chromatogram had light green pigment, while the Non-Green leaf had red and yellow pigments, as the image below shows. 

Green and Non – Green Leaf Chromatogram

      11. What else did you find out about pigments and photosynthesis?

Photosynthesis is the process that plants and algae go through to produce sugars from water molecules, carbon dioxide, and light energy. Chlorophyll is a special pigment in plants that allows photosynthesis to happen by absorbing light. Therefore, all organisms that go through photosynthesis must contain chlorophyll, which is the green pigment that can be seen in the leaves above.

      12. What are other questions you have?

Why is no green pigment seen in the non – green leaf, since chlorophyll must be present for photosynthesis to work?

 

A Plastic Ocean

Can you believe that 8 million tons of plastic are dumped into the ocean every year?! This startling fact is from the recent documentary, called A Plastic Ocean. This movie follows a man who decides to go whale watching, but comes across mounds of plastic in the ocean and finds out about the impact of micro plastics on humans and aquatic life. This film is a really good watch, full with eye-opening information and the various ways that people are trying to help the problem.

It was really hard to watch the scenes in which various wildlife was shown suffering because of the trash that is tossed in the ocean. Birds and whales alike were dying because plastic would fill their stomach and no more food could fit. So many creatures die because of starvation as a result of plastic. These plastics are broken down by the sun, UV radiation, waves, and salt into microplastics that are covered with toxic chemicals and are easier to swallow causing even more damage.

Marine mammals, like this seal, can get trapped in netting

There are people trying to fix the problem. In Haiti, the Plastic Bank is an organization that is trying to collect plastic from people and repurposes the otherwise wasted material, called social plastic. The donors get services such as charging or items, such as pots, for donating plastic. Initiatives like these will make this world a better place for humans, plants, and animals. We have to work together as a united human race to decrease the use of plastics by using reusable materials and properly dispose of the little waste produced. Small actions like this can change the world if everyone works together!

Please like and share any your thoughts in the comments below!

Citations:

NOAA Marine Debris Program. “Plastic Debris Such as Derelict Nets Can Entangle Marine Animals.” NOAA’S MARINE DEBRIS BLOG, NOAA, 27 June 2016, marinedebrisblog.wordpress.com/2016/06/27/plastics-in-the-ocean-how-they-get-there-their-impacts-and-our-solutions/.

 

 

Longest Swim CDQ

I investigated ocean currents along with the effect of currents on the aquatic ecosystem along with the impact on the Longest Swim.  Watch the video below to learn with me! To find out more about Ben Lecomte’s journey, read my blog on his journey.

 

 

Cell Membrane Project

Kelsey Sennet, Felicia Wei, and I worked on a cell membrane project to demonstrate all the parts and processes of the membrane. This membrane is semi-permeable, so it only allows certain molecules to enter. This is a very important part of the cell and the membrane takes care of many of the processes that go on from the outside to the inside of the cell.

F.L.O.W

Water is arguably the most important resource that every living organism requires. As Audrey Hepburn, a famous actress of her time, says, “Water is Life and Clean Water is Means Health”. There is nothing more sustaining than water. Then why do so many people lack access to water? This is a question that I started to contemplate as we watched F.L.O.W (For the Love Of Water) in class.  (Water Quotes)

F.L.O.W is a documentary about the issues that surround water: the privatization of the resource, and the lack of the water that many people around the world suffer from. The film transported its audience to many different places around the world including Bolivia, India, and the USA to show that everyone gets affected in some way by the problems associated with water. I was truly surprised to learn that 2 million people a year die from a waterborne disease, and most of them are under 5! That is a very startling fact, and it goes to show how important the purity of water is. The documentary also shows that only $30 billion a year can be spent to provide safe drinking water as opposed to $100 billion that is currently spent per year on water bottles. You and I are probably both wondering why that money is not being relocated, and it may be because many big corporations are trying to make a profit and spending that 30 billion dollars will not provide that.

The best things to take away from this film are the issues that are associated with water but most importantly future steps on how to solve them. We have to make people aware of the problems, and get everyone involved! It is essential to work together to make any change occur.

I would invite you all to spend some time watching F.L.O.W (For the Love Of Water) and learning more about the issues surrounding water. Also, you can calculate your Water Footprint and learn more about how YOU and your family can save water. Change starts small!

(Stoll, Christian)

Works Cited:

Stoll, Christian. “Inspiring and Educating Creative Entrepreneurs.” Pinterest, Pinterest, https://www.pinterest.com/pin/305048574739963869/

“Water Quotes & Sayings – Best Quotes about Importance of Water.” Best RO Water Purifier, BestROWaterPurifier, 22 Aug. 2018, www.bestrowaterpurifier.in/blog/water-quotes-sayings/.

Oil & Water Experiment

I recreated the Oil and Water Experiment done by Slick Science and explained how it works. Please enjoy!

 

The Longest Swim

Woohoo, my biology odyssey has finally begun! On the first day of school, Ms. Girard introduced us to The Longest Swim, and I was completely captivated by the idea. In summary, Ben Lecomte is swimming across the Atlantic Ocean from Tokyo to San Francisco, which is 5,500 miles. He is spending around 5 to 6 months in the ocean, swimming for 8 hours every day. My teammates and I had so many questions when this was introduced. We had a variety of inquiries from his personal experience to the science behind the swim and the research he is doing as he travels.

I was really interested in the equipment that he wore and how that was integrated into the process of swimming every day. To protect himself from sharks Mr. Lecomte wears a shark repellent bracelet that utilizes magnetic technology to interfere with the sharks’ electroreceptors causing the animal to not bother him. However, the band that is on market is pretty ineffective and only works when the shark is a mere 3-6 feet away. I’m curious if the swimmer uses the same band or had one custom made for him.

Ben Lecomte also has a rad band cesium collector that filters the water and collects cesium as he swims. From this, scientists can assess how much radioactive cesium from the Fukushima nuclear disaster and they can test it for radioactivity.

Overall, Mr. Lecomte’s story is extremely intriguing and the work he is doing is groundbreaking. I really recommend looking into The Longest Swim and learning more about it.

What do you think about this adventure? At what lengths would you go in the name of science?

(Lecomte, Ben)

Citations:

Lecomte, Ben. “[DAY 63] Every Day I Swim Is a Day to Celebrate Because: .” The Longest Swim, 10 Aug. 2018, benlecomte.com/day-63-every-day-i-swim-is-a-day-to-celebrate-because/.

Lecomte, Ben, and Ken Buesseler. “Radiation from Fukushima: an Interview with Dr. Ken Buesseler (Part 1).” The Longest Swim, 7 Jan. 2017, benlecomte.com/radiation-intvw-pt1/.

Swanson, Sharon. “2018 New Sharkbanz 2 vs Sharkbanz Shark Repellent Review .” Watch Yourselves, 9 Jan. 2018, watchyourselves.com/sharkbanz-2-shark-repellent-review/#tab-con-15.

The Odyssey Begins

My AP Bio journey has finally just begun! As I start my school year, I would like to share with you how much I have been looking forward to this journey. I have always wanted to take AP Biology ever since I was a young girl. The subject has always fascinated me and I have wanted to dive deeper into it. Now that I finally have that chance, I am ecstatic for all the new information I will learn and for all the new memories I will make. This summer has been filled with AP Bio from my homework to my trip to the Canadian Rockies! During my week in the mountains, the various sites led me to think about Biology and learning more about it. For instance, the various lakes in that area are all turquoise because they are filled with glacier water that has a special particle called rock flour in it. The particles become suspended in the water, and they refract light causing the gorgeous sea-green color to appear. I hope to share more updates as we go along!

A journey of a thousand miles begins with a single step. —Lao Tzu

All photos are original.