Dwayne Karlo Manzanillo Introduction Photosynthesis is the ability of using light energy to create

25 Jun Dwayne Karlo Manzanillo Introduction Photosynthesis is the ability of using light energy to create

Question
May you please improve the intro and the hypothesis.
First, improve the introduction
Second, improve the hypothesis and put them in an “if and then format”
Third, please make me a third hypothesis for the last leaf.

_______________________________________________

Dwayne Karlo Manzanillo

Introduction

Photosynthesis is the ability of using light energy to create macromolecules, which serves as a source for cellular respiration. The light energy is composed of photons, or packets of energy. These lights travel as waves of different wavelengths that thus, determine the amount of energy contained in the wave. Short wavelengths contain more energy than longer wavelengths since shorter wavelength can deliver more energy than the longer wavelength in the same time span. The way photosynthetic orgnims capture light energy is by pigment molecules designed to absorb a specific wavelength from the visible color spectrum and reflecting off the least absorbent wavelength. The three classes of photosynthetic pigments are the chlorophylls, carotenoids, and phycobilins. Chlorophyll is broken into multiple types of pigments from chlorophyll a and b. Chlorophyll has a high absorbance to red and violet wavelengths, and has a polar head and nonpolar tail that gives it properties to attract to both polar and nonpolar substances. Due to chlorophyll’s absorbance of red and violet wavelengths, the chlorophyll will thus reflect a green color of the photosynthetic organism. The second class of pigment is carotenoids which has an absorbance to blue wavelengths and are split into two classes, xanthophylls and carotenes. Xanthophyll has a structure that is mostly nonpolar, and beta carotene which is completely nonpolar. Due to carotenoids absorbance value to blue wavelengths, it can be assumed that the carotenoid pigment reflects yellow, orange, and red colors due to its lack of absorbance to them. The third class of pigment is phycobilins, which is very soluble to water found in algae and cyanobacteria. In this experiment, this pigment was not used.

To separate the pigment molecules from the photosynthetic organism, the method of paper chromatography is utilized. Chromatography uses the principle of separating molecules by polarity since molecules have a unique structure and composition that affects its polarity. The sample in which in this case of the experiment, the spinach plant, is placed onto the surface of a high filter paper and is place in a pool solvent ( in this case a solvent containing 90% petroleum ether and 10% acetone) at one end which diffuses through the paper. Substance containing different molecules will eventually separate due to their speed of the molecules diffusing across the filter paper by each pigments attraction to the solvent and filter paper. The distance traveled of the substance on the filter paper is proportional to the distance of the solvent, which creates a ratio or retention value, which helps identify each specific pigment if the retention value is already known for each pigment molecule. In retention value, the ratio will never exceed of 1 because the substance can only travel as far (or less) as the solvent moving the substance.

In this experiment, the solvent used is mostly nonpolar from its 90% petroleum ether with some polarity due to its 10% acetone because of its double bond of oxygen in its structure. The filter paper used is polar in order for the pigment to be less attracted to it and to be more attracted to the nonpolar solvent. The basic idea of polarity is the theory of two substances with similar polarity to be attracted to each other (also vice versa similar polarity dissolves the same polarity). By this knowledge, the hypothesis of the experiment is that, if the retention value of the substance has a ratio close to one (meaning that the substance is closer to the nonpolar solvent), then the substance is likely to be more nonpolar assuming that the solvent is nonpolar. Moreover, the second leaf used in the experiment is a green kukui nut leaf. Based on the idea of the relation of the distance traveled to the distance of the solvent being proportional, one can assume that two photosynthetic organisms with similar retention values can also have similar features as long as the experiment conditions are constant. By this knowledge, the second hypothesis is that since the kukui nut leaf and spinach leaf both show a physical feature of emitting a green color, then both the leaves should have similar retention values for the pigment molecules.

Results

The pigment molecules with the highest retention value were the carotenes and the xanthophyll. The spinach’s carotene highest retention value was 0.384 mm; the kukui’s carotene value and the third leaf values were the same, which is 1 mm. (Table 1, 2, 3). The pigment molecule with the lowest retention value was the Chlorophyll bin all leaves tested. The retention value of the chlorophyll b of the spinach was 0.070 mm; the retention value of the kukui leaf was 0.029 mm and the third leaf retention value was 0.043 mm (Table 1, 2, 3). Trends noticed in the experiment was the pigment molecule showing a different color. All of our leaves have had identical colors for the same pigment molecule. The color for chlorophyll b was a light green; chlorophyll a was green; xanthophyll had a yellow color and the carotene had a lighter shade of yellow. Another noticeable trend was the type of photosynthetic pigments of the chlorophylls (a and b) having the lower retention value than the other photosynthetic pigment, carotenoids (carotene and xanthophyll). The three leaves used in this experiment were a bright green color.

Table 1. The table below shows the results of the spinach leaf tested in retention value or ratio of the distance traveled over distance of solvent traveled in millimeters of the pigment molecules. Color observation, pigment name, Rf value and class average were also added.

Band Color

Distance from origin

Distance traveled

Rf value

Pigment name

Class average Rf value

Light green

6 mm

86 mm

0.070

Chlorophyll b

0.159

Green

10 mm

86 mm

0.116

Chlorophyll a

0.162

Yellow

16 mm

86 mm

0.186

Xanthophyll

0.908

Light Yellow

33 mm

86 mm

0.384

Carotene

0.390

Table 2. The table below shows the results of the kukui nut leaf tested in retention value or ratio of the distance traveled over distance of solvent traveled in mm of the pigment molecules. Color observation, pigment name, and Rf values were also added.

Band Color

Distance from origin

Distance traveled

Rf value

Pigment name

Light green

2 mm

69 mm

0.029

Chlorophyll b

Green

4 mm

69 mm

0.058

Chlorophyll a

Yellow

69 mm

69 mm

1

Xanthophyll

Table 3. The table below shows the results of the third leaf tested in retention value or ratio of the distance traveled over distance of solvent traveled in mm of the pigment molecules. Color observation, pigment name, and Rf values were also added.

Band Color

Distance from origin

Distance traveled

Rf value

Pigment Name

Light green

3

69

0.043

Chlorophyll b

Green

7

69

0.101

Chlorophyll a

Light yellow

29

69

0.420

Carotenes

Yellow

69

69

1

Xanthophyll