Photosynthesis and cellular respiration lab: 10 algae beads were placed in cuvet
ID: 196906 • Letter: P
Question
Photosynthesis and cellular respiration lab: 10 algae beads were placed in cuvettes labeled LIGHT and DARK with a color indicator and then LIGHT was placed under a bright lamp and DARK was placed next to it but wrapped in tinfoil. The pH was taken per the color indicator and the Absorbance was also taken (every 5 minutes for 45 minutes).
It was calculated that the slope LIGHT is 0.1261 and the slope DARK is -0.1491. pH increased the fastest in the LIGHT all the way up to 9.0 after 45 minutes and the ph DARK began at 8.0 but then slowly decreased to 7.0 after 45 minutes
1. Revise the diagram below to demonstarte how the expiremental design of the investigation affects these processes. Indicate where the rates of these processes may increase or decrease and describe why. Also indicate how the organism will be affected if the conditions continue.
Co 2 SugarExplanation / Answer
Algae is a wonderful model organism to study photosynthesis. In the given question, an experiment has been conducted using algal beads. Two key observations were made in this experiment:
a. In the LIGHT cuvette, pH increased all the way up to 9 after 45 minutes.
b. In the DARK cuvette, pH began at 8 and drastically reduced to 7 after 45 minutes.
From the given figure, we can understand that the grana in algal beads, when exposed to light (LIGHT cuvette), underwent photosynthesis and released oxygen and sugar. This increased the pH up to 9.
In the DARK cuvette, algal beads had already produced some glucose and thus the initial pH was 8. During this stage, stroma underwent cellular respiration and utilized glucose and oxygen to produce carbon dioxide and water. The release of CO2 increased the acidity and after 45 minutes pH was stabilized to 7.0.
So, two process takes place in this experiment. They are photosynthesis and cellular respiration.
Now let's solve the questions
Revise the diagram below to demonstrate how the experimental design of the investigation affects these processes.
The increase or decrease in the rate of photosynthesis depends on two factors light intensity and CO2 concentration. So, in the given experiment if we alter the initial concentration of CO2 and light intensity it affects the rate of photosynthesis. Let us take the example of light intensity. If we expose the algal beads to low-intensity light, the production of glucose and O2 drastically reduces and the pH of the solution changes to the acidic state. The rate of photosynthesis changes in grana of chloroplasts.
The increase or decrease in the rate of cellular respiration depends on the concentration of glucose and oxygen. So, in the given experiment if the DARK cuvette is kept in an anaerobic condition, the rate of cellular respiration reduces in mitochondria and chloroplast and the acidity decreases. The rate of cellular respiration reduces in stroma and in mitochondria.
If these two conditions are continued, the algae will eventually die due to the reduction in glucose production and ATP synthesis through cellular respiration.