Unit 3 Reflection

Unit 3 Reflection

This unit was all about cells and how they function. We learned about cell organelles and other parts, the different kinds of cells, how cells make energy, and more. Some essential topics o understand were photosynthesis and cellular respiration. Plants and other autotrophs use photosynthesis to make ATP (energy). Cells use cellular respiration also. I had trouble understanding how the energy is converted during photosynthesis and how and why cellular respiration takes place in a cell.  I was good at memorizing which organelles go where in the different types of cells. I am a better student than I was yesterday, because I know more about how the organelles even came to be and more, and I've learned better studying techniques and efficient ways to get my work done both in and out of class.  I want to learn more about photosynthesis because I think its super cool that plants can make their own energy, and I think its amazing how everything comes together to make ATP.  My only question was when plants/ cells started using photosynthesis to make energy, like if they always did or if that was something they developed to survive. I wonder = if cells that are both autotrophs and heterotrophs primarily survive off photosynthesis or other organisms, or if different cells use the two differently.

http://www.guidrybiology.com/biology-hp/unit-2

http://tomatosphere.org/teachers/guide/grades-8-10/plants-and-light

Photosynthesis Virtual Labs

Photosynthesis Virtual Labs

Analysis Questions

1. Make a hypothesis about which color in the visible spectrum causes the most plant growth and which color in the visible spectrum causes the least plant growth?

If the color blue is absorbed the most by plants, then if we expose a plant to blue light it will grow the most.

If the color green is reflected by plants, then if we expose a plant to green light, it will grow the least.

2. How did you test your hypothesis? Which variables did you control in your experiment and which variable did you change in order to compare your growth results?

I tested my hypothesis by exposing identical spinach plants to different colors of light. We controlled the location, the size pot, the type of plant, and the amount of the light. We changed the color of the light.

Results:

Filter Color	Spinach Avg. Height (cm)	Radish Avg. Height (cm)	Lettuce Avg. Height (cm)
Red	18
Orange	14
Green	2
Blue	19
Violet	16

3. Analyze the results of your experiment. Did your data support your hypothesis? Explain. If you conducted tests with more than one type of seed, explain any differences or similarities you found among types of seeds.

Yes, the data supported my hypothesis, because the plant exposed to the blue light grew the most, (19 in.) and the green light was the least ( 2in.)

4. What conclusions can you draw about which color in the visible spectrum causes the most plant growth?

I can draw the conclusion that blue and red light cause the most plant growth, because in my experiment they grew 19 and 18 in, which was the most.

5. Given that white light contains all colors of the spectrum, what growth results would you expect under white light?

I would expect a plant under white light would grow an average height, in between blue and green.

• Question::  How does temperature affect the rate of photosynthesis in a plant?
• Hypothesis :: If plants normally grow at room temperature, then when the temperature is at 25 degrees celsius, the plant will grow the most.
• Experimental parameters (in other words, what is the dependent variable, independent variable, and control?)

The dependent variable is the rate of photosynthesis in the plant. The independent variable is the temperature of the water surrounding the plant. The control is room temperature (25 degrees celsius)

test number	temp	rate
1	10	8 bubbles/ 20 sec
2	25	22 bubbles/ 20 sec
3	40	18 bubbles/ 20 sec

In this lab we were observing the effect of temperature on the rate of photosynthesis in a plant. I found that at the temperature of 25 degrees celsius the rate of photosynthesis was highest. I knew this because it created 22 oxygen bubbles per 20 seconds, as opposed  to 8 oxygen bubbles per 20 seconds (10 degrees celsius)  and 18 oxygen bubbles per 20 seconds (40 degrees celsius). This makes sense because most plants survive at relatively normal temperatures, so when the plant is too hot or too cold the reaction slows. This data supports our claim because the middle temperature (25 degrees celsius) had the fastest rate, and the 10 and 40 degree temperatures were slower.

This lab was done to demonstrate the effects of external environments on the plant’s internal environment. From this lab I learned how temperature affects how a plant cell works, which helps me understand the effect of ph and temperature, like in the egg lab. Based on my experience from this lab,  I could further study the effects of global warming on a plant cell’s internal structures.

Egg Diffusion Lab

Egg Diffusion Lab

In this experiment, we were observing how an egg's internal environment changed as its external environment changed.  After removing the egg's shell by soaking it in vinegar, we left the eggs either in a sugar/ water solution and deionized water, then, after around 48 hrs of soaking, measured that change in both mass and circumference in each egg.

 When the egg was placed in deionized water, it grew slightly (.176%)  in mass, and there was no change in circumference, most likely because we had previously soaked in tap, not deionized water.  The egg most likely grew a little because inside the egg's membrane there was a higher amount of sugar (solute) and less solvent (water) than outside the egg, which was all solvent. Since the sugar in the egg was too big to diffuse through the egg's membrane, the egg took more water in through passive diffusion, because the water was moving from high concentration to the low concentration inside the egg's membrane.  

When the egg was placed in sugar water, a hypertonic solution,  it's mass decreased by 51.7% on average and its circumference decreased by 23.67%.  This is because the sugar water surrounding the egg contained more solute than the egg, and so to balance the concentrations, water was released from inside the membrane in order to make the sugar concentrations inside higher, leading to decreases in both mass and circumference.  

A egg cell's internal environment changes in both mass and circumference as it's external environment changes, in order to balance the concentrations of solutes and solvents. When we added the vinegar around the egg, I think that the egg's mass and circumference changed because the egg might have taken in some of the vinegar solution. When we put the egg in water, (tap water) the egg might have also taken in some of the contaminants in the water. When we put the egg in sugar, it shrunk because it let out some out the water inside in order to balance the concentrations  of the internal and external environments.

This lab demonstrates the biological principle of diffusion and solutes and solvents by showing us a real life example. Since the sugar was too big to diffuse through the cell's membrane, the cell lost and gained water. When the egg was placed in a solution with more solute than inside the egg, it shrunk, because the sugar water was a hypertonic solution. When the egg was placed in the deionized water, which had more solvent than inside, it grew slightly, because the deionized water was a hypotonic solution.

Fresh vegetables are sprinkled with water at markets because water will diffuse into them making them fresher and plumper. When salt is used on roads and get near the plants on the side of the road, it kills them because the water diffuses out of the plant, and shrivels the plant, and so it dies.

Based on this experiment, I would want to test celery to see how leaving in in different concentrations of water, sugar, and salt would affect it.  It would be relatively easy to detect changes in the celery, as they are straight. We could also try this experiment with vegetables such as lettuce and spinach. 

Egg Cell Macromolecule Analysis

Egg Cell Macromolucule Analysis

           In this experiment, we were trying to find out if we could identify macromolecules in a egg cell. We found that we could, in fact, identify the macromolecules, in each part of the egg cell. (egg membrane, egg white, and egg yolk). 

 In the egg membrane we found lipids, polysaccharides, and proteins. When we added Sudan III and water to the sample, it turned orange, meaning that the macromolecule (lipid) was present. This is because lipids make up most cell membranes.  We also found polysaccharides were in the membrane. We knew because the membrane turned black when we added iodine, because polysaccharides are found on the surface of cells. When we added the sodium hydroxide and copper sulfate, the solution should have turned purple, however, due to testing errors, ours didn't. It should have because transport proteins are found in cell membranes.
In the egg yolk we found monosaccharides, polysaccharides, lipids, and proteins. When we added benedicts solution to the sample, it turned green, meaning that there were monosaccharides present in the yolk, because they store the egg's energy.  When we added iodine to the sample, it turned black, suggesting that polysaccharides were present. This is because they are in the cytoplasms of cells and store energy for the cell. We also found lipids present in the yolk. We know because when we added Sudan III to our sample, it turned orange. This is because they store energy inside the cell.  When we added sodium hydroxide and copper sulfate, we should have found that the solution turned purple because proteins, which are found in the cells organelles, were in the sample.
In the egg white, we found polysaccharides, monosaccharides, and proteins. When we added iodine to the sample, it turned black, suggesting that polysaccharides were there. This is because polysaccharides are used for growth and development of the egg. When we added benedicts solution, it turned green, indicating that monosaccharides were there. This is because they store energy for growth and development. When we added sodium hydroxide and copper sulfate the sample turned purple, indicating that proteins were present, because they are needed for both growth and development and to make enzymes for immunity. This data supported our claim because it showed what we used to identify the different macromolecules.

While our hypothesis supported our data, there could have been errors due to contamination with other egg parts, or inaccurate measurements of the solutions added to our samples. By contaminating the egg parts, you could accidentally put some macromolecules where they normally aren't, leading us to believe that they regularly are there. If our measurements were inaccurate, we could have missed a macromolecule which was present. (In the protein test most samples didn't turn purple) Due to these errors, in future labs I would recommend being more careful measuring the solutions and separating the egg parts.

This lab was done to demonstrate the roles of the different macromolecules in the different part of the cell. From this lab I learned a real world example of what the different macromolecules were used for, which helped me understand the concept of how they are used in the cellular level. Based on my experience from this lab, I could identify the macromolecules in a different type of cell or egg, using the techniques we learned in this lab.