Biology Today: Photosynthesis And Cellular Respiration First

Biology Todayphotosynthesis And Cellular Respirationfirst And Last Nam

Biology Today Photosynthesis and Cellular Respiration First and Last Name__________________________ Section________ This is a 12 point assignment. The objective of this assignment is to spend hours thinking and understanding the physiological pathways of Photosynthesis and of Glycolysis and Cellular respiration. The more time you spend looking at these physiological cycles, extrapolating and interpreting, the more comprehension you’ll achieve. This assignment can act as a study tool and should add towards your overall study time for Unit 2. Point Distribution: Chapter 8 Cycle Drawings = 3 points Chapter 8 Cycle 1 page Explanation Paper = 3 points Chapter 7 Cycle Drawings = 3 points Chapter 7 Cycle 1 page Explanation Paper = 3 points Total Points for Chapter 8 & 7 Assignment = 12 points

For chapter 8: Draw out on a blank 8X11 sheet of paper the two diagrams below. The first diagram is summary of the pathways of electrons through the PHOTOSYSTEMS and through the ELECTRON TRANSPORT CHAINS. The second diagram is the summary of the CALVIN (or C3) CYCLE. You must know the ins and outs of these two important pathways which all begin with light and water. DON’T JUST COPY the diagrams for the sake of completing the assignment, this completely defeats the objective of the assignment. Rather, think of why each step in the process is necessary and how each step assists in the pathway. Be sure to label all parts of the systems and cycles. Then on a second sheet of paper, write in your own words the physiological pathway or story explaining all steps of all reactions from the beginning of the reaction center to the end of the C3 Cycle. You must include in your paper the following terms in order to receive full credit: NADPH, NADP,+ H,+ ADP, ATP, H2O, O2, CO2, e,- NADP, ETC II, ETC I, Photosystem II, Photosystem I, Reaction center, Light, Photons, Primary electron acceptor, Chlorophyll, Stroma, Pigment molecules, Thylakoid, ATP Synthase, Glucose, Light-independent, Light-dependent, Chemiosmosis, Calvin Cycle, Kinetic energy, Concentration gradient, Hydrogen pump, rubisco, G3P (glyceraldehyde 3-phosphate), RuBP, PGA (Phosphoglyceric acid), KEEP GOING

For chapter 7: Do the exact same thing as you did for Photosynthesis. The diagrams below depict: Glycolysis Pyruvate Oxidation (Acetyl CoA formation) Krebs Cycle (Citric Acid Cycle) Oxidative Phosphorylation (Electron Transport Chain & Chemiosmosis) Fermentation (Lactate forming). Draw out on a blank 8X11 sheet of paper the diagram below. Be sure to label all parts of the systems and cycles. Then on a separate page, write a story explaining all steps of all reactions from the beginning of Glycolysis to the end of the ETC. I will be looking for ATP, ADP, FAD, FADH2, Acetyl-CoA, Pyruvate, G3P, Glycolysis, Cellular respiration, glucose, concentration gradient, ATP synthase, kinetic energy, rotor, catalytic knob, stator, internal rod, depleted electrons, Krebs cycle, Ribulose 1,6-Biphosphate, NADH, NAD+, Chemiosmosis, Oxidative phosphorylation, CO2, H2O, O2, electrons (e-), lactate or ethanol, aerobic, anaerobic

Paper For Above instruction

The processes of photosynthesis and cellular respiration are fundamental to life on Earth, providing the energy necessary for growth, reproduction, and maintenance of all living organisms. Understanding these complex pathways involves analyzing the intricate steps of electron transport, energy conversion, and synthesis of organic molecules, which are vital to cellular function and energy management.

Photosynthesis Pathway

Photosynthesis primarily occurs in the chloroplasts of plant cells, involving two main stages: the light-dependent reactions and the light-independent Calvin cycle. The journey begins with photons being absorbed by pigment molecules—mainly chlorophyll—located within the photosystems embedded in the thylakoid membranes. Photosystem II captures light energy, exciting electrons in chlorophyll molecules. These high-energy electrons are transferred to the primary electron acceptor and then passed through the electron transport chain (ETC I). As electrons move through ETC I, they facilitate the pumping of hydrogen ions (H+) into the thylakoid lumen via a hydrogen pump, creating a concentration gradient. This gradient drives ATP synthesis through chemiosmosis facilitated by ATP synthase. Simultaneously, electrons reduce NADP+ to form NADPH, storing energy for the Calvin cycle.

The electrons then flow into Photosystem I, where additional photons excite the electrons further. These electrons are transferred to another primary acceptor and ultimately reduce NADP+ again, forming NADPH. The ATP and NADPH produced are then used in the Calvin cycle situated in the stroma, the fluid surrounding the thylakoids. In this cycle, carbon dioxide (CO2) is fixed into organic molecules through the action of the enzyme rubisco, forming 3-phosphoglyceric acid (PGA). PGAs are then converted into G3P molecules, some of which exit the cycle to form glucose, while others regenerate RuBP, enabling continuous carbon fixation.

Cellular Respiration Pathway

Cellular respiration is the process by which glucose is broken down to produce energy stored as ATP, vital for cellular activities. The process begins with glycolysis in the cytoplasm, where one molecule of glucose is split into two molecules of G3P, producing a net gain of 2 ATP molecules and 2 NADH molecules. Pyruvate then enters the mitochondria, where it is oxidized to form Acetyl-CoA, releasing CO2 in the process. This Acetyl-CoA feeds into the Krebs cycle (Citric Acid Cycle), occurring in the mitochondrial matrix. The Krebs cycle further oxidizes Acetyl-CoA, generating NADH and FADH2 molecules, and releasing CO2 as a byproduct.

The high-energy electrons from NADH and FADH2 are transferred to the electron transport chain located in the inner mitochondrial membrane. As electrons pass through ETC II and ETC I, their energy is used to pump protons into the intermembrane space, creating a proton gradient. In oxidative phosphorylation, this gradient drives ATP synthesis as protons flow back through ATP synthase, converting kinetic energy into chemical energy, producing a total of about 30-34 ATP molecules per glucose molecule. Water is formed when electrons combine with oxygen, the final electron acceptor, thus completing the process.

Fermentation occurs under anaerobic conditions, where lacking oxygen, cells regenerate NAD+ by converting pyruvate into lactate or ethanol, allowing glycolysis to continue producing ATP without oxygen. This process results in less ATP compared to aerobic respiration but is essential for energy production in oxygen-deprived environments.

Conclusion

Both photosynthesis and cellular respiration are interconnected processes that sustain life by converting energy from sunlight into chemical energy and vice versa. Photosynthesis captures solar energy and synthesizes glucose, while cellular respiration releases this stored energy for cellular activities. A comprehensive understanding of these pathways reveals the elegance of biological energy management and the critical roles these cycles play in the biosphere.

References

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