Introduction
In the Foundations of Biology lab section everyone had to investigate cell organelles and cellular metabolism. Every quad or tri group had to test for the activity of a chloroplast electron transport chain. The two choices that were available for us to investigate was broccoli and pea seedlings. Our group was nominated to utilize 20 grams of broccoli florets to find fractions that composed of an abundance of chloroplast. Project 1 had 3 parts to it; this consists of fractionation of cell homogenates, assay for chloroplast-specific electron transport chain activity, and testing factors that affect activity of the chloroplast electron transport chains. The first two parts of this project is Experiment #1, while part 3 is Experiment …show more content…
The plant tissue that was used for this cell fractionation process was 20g of broccoli. To start off the cell fractionation sequence, the broccoli florets were combined together with 2.5 grams of fine sand and 30 ml of ice-cold Chloroplast Isolation Buffer (CIB) in a chilled mortar. After the substance is pureed finely, it is then transferred to a tube using a damp cheesecloth. This filters the unwanted cell organelles that are not needed in this experiment. The product that is in the tube is the filtrate portion of this experiment and will be centrifuged. The first centrifuge is at 600 x g for 5 minutes; large components (pellet) will be settled at the end, while the small components are still soluble (supernatant). The tube is called Pellet 1(P1), we transfer it again by adding the supernatant to tubes labeled Supernatant 1(S1). 15ml of S1 will be added to a tube called P2; the centrifuge process is applied once more using P2 at 2000 x g for 10 minutes. The supernatant of the centrifuge product is transferred over to a tube named S2. 20ml of CIB should be added to P1 and 10ml of CIB should be added to P2 right after transfer of supernatants to their respective tubes. Now that we have the particular tubes (P1, P2, and S2), each tubes will be split into 3 subgroups. The cuvettes that are named blanks are used for calibration …show more content…
Green actually had a negative change of -5.33%. Blue had change of 6.25% in absorbance. Dark had no change at all.
Discussion
The group established that the hypothesis for Experiment #1 was P2 would have the most intact chloroplasts prior to the past knowledge from our lab. Our hypothesis was right but the experiment definitely did not go that smooth. We had plenty of human error during the Spectronic 20 reading phase of Experiment #1. For the first few readings we forgot to put the specific cuvettes to their proper destination. This can account for the huge change in our P2 and S2 negative control; which are the ones that were supposed to go in a dark container. This can be closely observed with figure 2. Overall, it answered our hypothesis of abundancy of chloroplast in P2. The group established the hypothesis for Experiment #2 was that chloroplast would have the most absorbance change in the green light compared to the blue light. This one went smoother than Experiment #1 but our hypothesis was proven wrong. This is because the color blue has a higher frequency than green; this makes it a better transmission of illumination. Overall, we made less mistakes and timed our intervals accordingly for this
In the Foundations of Biology lab section everyone had to investigate cell organelles and cellular metabolism. Every quad or tri group had to test for the activity of a chloroplast electron transport chain. The two choices that were available for us to investigate was broccoli and pea seedlings. Our group was nominated to utilize 20 grams of broccoli florets to find fractions that composed of an abundance of chloroplast. Project 1 had 3 parts to it; this consists of fractionation of cell homogenates, assay for chloroplast-specific electron transport chain activity, and testing factors that affect activity of the chloroplast electron transport chains. The first two parts of this project is Experiment #1, while part 3 is Experiment …show more content…
The plant tissue that was used for this cell fractionation process was 20g of broccoli. To start off the cell fractionation sequence, the broccoli florets were combined together with 2.5 grams of fine sand and 30 ml of ice-cold Chloroplast Isolation Buffer (CIB) in a chilled mortar. After the substance is pureed finely, it is then transferred to a tube using a damp cheesecloth. This filters the unwanted cell organelles that are not needed in this experiment. The product that is in the tube is the filtrate portion of this experiment and will be centrifuged. The first centrifuge is at 600 x g for 5 minutes; large components (pellet) will be settled at the end, while the small components are still soluble (supernatant). The tube is called Pellet 1(P1), we transfer it again by adding the supernatant to tubes labeled Supernatant 1(S1). 15ml of S1 will be added to a tube called P2; the centrifuge process is applied once more using P2 at 2000 x g for 10 minutes. The supernatant of the centrifuge product is transferred over to a tube named S2. 20ml of CIB should be added to P1 and 10ml of CIB should be added to P2 right after transfer of supernatants to their respective tubes. Now that we have the particular tubes (P1, P2, and S2), each tubes will be split into 3 subgroups. The cuvettes that are named blanks are used for calibration …show more content…
Green actually had a negative change of -5.33%. Blue had change of 6.25% in absorbance. Dark had no change at all.
Discussion
The group established that the hypothesis for Experiment #1 was P2 would have the most intact chloroplasts prior to the past knowledge from our lab. Our hypothesis was right but the experiment definitely did not go that smooth. We had plenty of human error during the Spectronic 20 reading phase of Experiment #1. For the first few readings we forgot to put the specific cuvettes to their proper destination. This can account for the huge change in our P2 and S2 negative control; which are the ones that were supposed to go in a dark container. This can be closely observed with figure 2. Overall, it answered our hypothesis of abundancy of chloroplast in P2. The group established the hypothesis for Experiment #2 was that chloroplast would have the most absorbance change in the green light compared to the blue light. This one went smoother than Experiment #1 but our hypothesis was proven wrong. This is because the color blue has a higher frequency than green; this makes it a better transmission of illumination. Overall, we made less mistakes and timed our intervals accordingly for this