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Photosynthesis and Cellular Respiration Questions

Explain how photosynthesis and respiration are linked in order to provide you with energy from the food you eat.
Include in the essay:
Complete descriptions of photosynthesis and aerobic respiration.
Describe how these two processes are linked between plants and animals based on the reactants and products (water, carbon dioxide, glucose and oxygen) of both pathways.
Include a description of how energy is transferred from sunlight to ATP, from ATP to sugars, and from sugars to your cells.

2. In the absence of oxygen some cells and organisms can use glycolysis coupled to fermentation to produce energy from the sugar created by photosynthesis.

Explain the role of fermentation in allowing an organism to generate energy for its cell(s) in the absence of oxygen.
Include any reactions required for this process, and explain how the energy from the sun ends up as chemical energy for the anaerobic organism or cell.

3. Cells use enzymes as biological catalysts to increase or accelerate the rate of reactions, such as those in photosynthesis or glycolysis. This allows reactions to occur under conditions that sustain life.

Explain how an enzyme catalyzes a reaction. Include in your essay the three main steps of the cycle of enzyme-substrate interactions.
How is enzyme activity regulated by the cell?

Reference:
Audesirk, T., Audesirk, G., and Byers, B. (2008). Biology - Life on earth with physiology (8th Ed.). San Francisco, CA: Benjamin Cummings.

The essays should be several paragraphs in length for each question, be thoroughly paraphrased, and include appropriate in-text citations and a reference list in APA format.

Solution Preview

Cytology, the operation of cells
Explain how photosynthesis and respiration are linked in order to provide you with energy from the food you eat.
Include in the essay:
Complete descriptions of photosynthesis and aerobic respiration.
Describe how these two processes are linked between plants and animals based on the reactants and products (water, carbon dioxide, glucose and oxygen) of both pathways.
Include a description of how energy is transferred from sunlight to ATP, from ATP to sugars, and from sugars to your cells.

Photosynthesis reaction converts CO2 and water into sugars and O2. The overall equation for photosynthesis is 6CO2 + 6 H20 ----- C6H1206 + 602. Photosynthesis is a redox reaction ( meaning oxidation-reduction) just like cellular respiration. Photosynthesis use light energy to reduced C02 to sugar when electrons and hydrogen ions are added to it in a process of reduction. Water molecule is split apart into 02 and hydrogen ion (H+) in a process called oxidation.

Photosynthesis involve two stages: Light reaction and Calvin cycle
The light reaction convert light energy to chemical energy and produce O2. Light energy is absorbed by chlorophyll and is used to drive the transfer of electrons and H+ from water to NADP+, reducing it to NADPH. NADPH is an electron carrier that stored the electron and provide reducing power to Calvin cycle. The light reaction generate ATP from ADP and a phosphate group. The light reaction of photosynthesis take in solar energy and convert it to chemical energy stored in ATP and NADPH. The light reaction does not produce sugars yet. The light reaction occur in the thylakoid membrane.

The light reaction contains two photosystems connected by an electron transport chain that generate ATP and NADPH. In the light reaction, the light energy is converted into ATP ad NADPH. Electrons is removed from water and pass from photosystem II to photosystem I to NADP+. The electrons move down an electron transport chain ( similar to cellular respiration) and provide energy for the synthesis of ATP.

Steps of the light reaction:
1. Light is absorb by the reaction center of photosystem II where the electron of chlorophyll P680 is excited to a higher energy state.
2. Electron is captured by the primary electron acceptor and combines with an oxygen from another split water molecule to form O2.
3. Each photoexcited electron is passed from photosystem II to photosystem I via an electron transport chain. The exergonic fall of electrons provide energy for synthesis of ATP by pumping H+ across the membrane.
4. Light energy excites an electron of chlorophyll P700 in the reaction center of photosystem I. The excited ...

Solution Summary

Photosynthesis reaction converts CO2 and water into sugars and O2. The overall equation for photosynthesis is 6CO2 + 6 H20 ----- C6H1206 + 602. Photosynthesis is a redox reaction ( meaning oxidation-reduction) just like cellular respiration. Photosynthesis use light energy to reduced C02 to sugar when electrons and hydrogen ions are added to it in a process of reduction. Water molecule is split apart into 02 and hydrogen ion (H+) in a process called oxidation.
Cellular respiration is the process that used the chemical energy of the bonds in glucose and transferred as well as stored the energy in the form of ATP. Cellular respiration produce 38 ATP molecules from each glucose molecule.

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