Solved by a verified expert:May you please improve the intro and the hypothesis.First, improve the introductionSecond, 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
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