Tran Nguyen
Professor Pate
BIO 180 Lab
CRN 60106
04/03/2018
Lab #8: Metabolism
Introduction
Photosynthesis is the process of using sunlight energy to synthesize carbohydrate (CH2O)
from carbon dioxide (CO2), which occurs in the chloroplast where contains chlorophyll
molecules. However, plants continuously undergo cellular respiration, which uses carbohydrate
to produce carbon dioxide. In fact, when plants are exposed to light, there occurs to be both
photosynthesis and cellular respiration; and when plants are in the dark, there occurs only
cellular respiration. Moreover, fermentation is the process of metabolizing glucose into ethanol
(C2H5OH) and carbon dioxide and producing limited amounts of ATP. Finally, paper
chromatography is based on differential adsorption, which is based on variances in solubilities
due to polarity differences, of a solute between the mobile and stationary phases.
Due to the relationship of CO2 and pH, there is a pH indicator called phenol red which
helps determine the increase or decrease of pH in the solutions. As CO2 increases, pH decreases
which means the solution turns more acidic, and vice versa. The neutral color of phenol red is
red; its acidic state’s color is yellow, and the basic state’s color is hot pink.
In exercise 1, some pieces of elodea are put in two solutions of phenol red – one with
light and one without light, to discover the amount of CO2 in the solutions using the
spectrophotometer. In exercise 2, yeast is used to perform the experiment of fermentation, which
releases CO2, and the absorbance values are taken based on the behavior of phenol red with its
relationship to CO2 and pH. In exercise 3, using ascending chromatography, different pigments
found spinach (carotene, chlorophyll a, chlorophyll b, and two xanthophylls) are separated in the
chamber containing 9:1 petroleum ether/acetone.
1
, Tran Nguyen
Photosynthesis/Respiration Results and Discussion
1) What are the colors of the phenol red solutions after 30 minutes?
Control-E solution: yellow orange
Elodea with light: strawberry red
Elodea with no light: slightly orange
Without light
With light
Control-E
Figure 1. Phenol Red Solutions of Elodea in Different Environments
2) What are the absorbance values of the following phenol red solutions?
Control-E solution (0 min): 1.18
Control-E solution (30 min): 1.19
Elodea with light (30 min): 0.91
Elodea with no light (30 min): 1.15
2
Professor Pate
BIO 180 Lab
CRN 60106
04/03/2018
Lab #8: Metabolism
Introduction
Photosynthesis is the process of using sunlight energy to synthesize carbohydrate (CH2O)
from carbon dioxide (CO2), which occurs in the chloroplast where contains chlorophyll
molecules. However, plants continuously undergo cellular respiration, which uses carbohydrate
to produce carbon dioxide. In fact, when plants are exposed to light, there occurs to be both
photosynthesis and cellular respiration; and when plants are in the dark, there occurs only
cellular respiration. Moreover, fermentation is the process of metabolizing glucose into ethanol
(C2H5OH) and carbon dioxide and producing limited amounts of ATP. Finally, paper
chromatography is based on differential adsorption, which is based on variances in solubilities
due to polarity differences, of a solute between the mobile and stationary phases.
Due to the relationship of CO2 and pH, there is a pH indicator called phenol red which
helps determine the increase or decrease of pH in the solutions. As CO2 increases, pH decreases
which means the solution turns more acidic, and vice versa. The neutral color of phenol red is
red; its acidic state’s color is yellow, and the basic state’s color is hot pink.
In exercise 1, some pieces of elodea are put in two solutions of phenol red – one with
light and one without light, to discover the amount of CO2 in the solutions using the
spectrophotometer. In exercise 2, yeast is used to perform the experiment of fermentation, which
releases CO2, and the absorbance values are taken based on the behavior of phenol red with its
relationship to CO2 and pH. In exercise 3, using ascending chromatography, different pigments
found spinach (carotene, chlorophyll a, chlorophyll b, and two xanthophylls) are separated in the
chamber containing 9:1 petroleum ether/acetone.
1
, Tran Nguyen
Photosynthesis/Respiration Results and Discussion
1) What are the colors of the phenol red solutions after 30 minutes?
Control-E solution: yellow orange
Elodea with light: strawberry red
Elodea with no light: slightly orange
Without light
With light
Control-E
Figure 1. Phenol Red Solutions of Elodea in Different Environments
2) What are the absorbance values of the following phenol red solutions?
Control-E solution (0 min): 1.18
Control-E solution (30 min): 1.19
Elodea with light (30 min): 0.91
Elodea with no light (30 min): 1.15
2
