Rate of Photosynthesis Lab Report

Document Type:Lab Report

Subject Area:Biology

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As these variations are being made, the number of bubbles produced per minute as well as the total number of bubbles produced within 3 minutes are detected and recorded down. The results indicated that the closer the light source from the elodea plant, the more the air bubbles per minute are recorded as well as the total number of the bubbles produced in three minutes, pointing to the fact that the closer the light source the higher the light intensity, the more light is trapped by the chlorophyll in the chloroplasts and higher the photosynthesis and photosynthetic rate Introduction Question The experiment seeks to answer the experimental question: How does variation of the light intensity affect the rate of photosynthesis (as measured by oxygen production in elodea plant)?The experiment heavily relies on the scientific principle that plants requires light besides carbon (IV) oxide water and favorable temperature, in which oxygen gas is given off as a by-product, hence by keeping other factors constant and introducing varying intensities of light, one can find out the rate of plant photosynthesis by observing the rate of oxygen bubbles produced (Nazos, Kokarakis & Ghanotakis, 2016). Various factors have an effect in the rate at which photosynthesis occurs. These factors when varied can either increase or decrease the speed at which photosynthesis occurs. The main factors that have this effect are; temperature, light intensity, and the concentration of carbon dioxide present (Huotari, Korpelainen, Leskinen & Kostamo, 2011). Materials • Source of light • Test tube • Millimeter calibrated ruler • Bubble measuring device • Clock • Water • Immersed elodea plant.

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Hypothesis “The rate of photosynthesis increases with increase in the light intensity up to an optimum level after which the process remains constant. ” The key variable under investigation is the distance separating the light source and the elodea plant, and the measurable parameter are the resultant oxygen bubbles produced as photosynthetic by-product. Precaution This experiment did not require toxic or hazardous reagents, therefore, there was little or no risk to the operator. Nevertheless, care had to be taken while dealing with the plant as well as the water to avoid contact with the plant and unnecessary spillage. The “Beat per Minute” (BPM) tab was chosen and this facilitated the calculation of bubbles produced per minute. The “Tap” button was clicked whenever a bubble was seen floating towards the top of test tube, this was done for 3 minutes and facilitated the count of bubbles produced per minute which was recorded in the data table.

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The “Counter” tab was chosen to facilitate the counting of the total number of bubbles produced; this enabled the obtaining of data recorded as total number of bubbles produced within three minutes. The + tab was clicked whenever a bubble floating to the top of test tube was seen, this was done for and the resultant total number of bubbles formed were recorded in the data table, the “+” tab was used to obtain the cumulative number of bubbles. “Back” button was clicked and the light source adjusted so that it sat at 190mm mark from the test tube, this enabled photosynthesis to occur at anew distance from the previous 160mm 10. Therefore photons absorbed from the light source in both stages are then processed through the thylakoid membranes simultaneously. These photons excite the chlorophyll electrons which proceed through the electron transport chain causing the NADP to fuse with H+ producing NADPH, and ADP emanating from the dark stage combines with the third phosphate to produce adenosine triphosphate ATP (Unger, 2015.

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All the produced oxygen emanates from water molecules via photolysis during the light-dependent stage. These oxygen molecules produced as the by-products will therefore vary as a function of photons reaching the thylakoids in the chloroplast (Li, Liu, Zhou, Huang & Duan, 2016). As per the result above, at a distance of 120mm between the plant and the light source the rate of photosynthesis is higher (99 bubbles per minute )as more light photons are absorbed by the chlorophyll and reach the thylakoid membranes, hence more oxygen bubbles are produced as the measurable indicator for this faster photosynthetic rate. Possible future researches arising from this could measure the rate of respiration in presence of all photosynthetic requirement and try to assess its relative effect on photosynthesis. Reference Unger, E. Wpływ niektórych wielofenoli na asymilncję i oddychanie moczarki kanadyjskiej Elodea canadensis i liści bożodrzewu Ailanthus glandulosa [The influence of some polyphenols on the photosynthesis and the respiration of Elodea canadensis and of leaves of Ailanthus glandulosa].

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 Acta Societatis Botanicorum Poloniae, 31(1), 3-24. doi. org/10. srep24895 Huotari, T. Korpelainen, H. Leskinen, E. Kostamo, K. doi. org/10. s00606-011-0442-2 Nazos, T. Kokarakis, E. Ghanotakis, D.

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