Biology Chapter 6 & 7

The products of the Calvin cycle, such as glucose, can be used as a starting point to synthesize various organic compounds. Carbohydrates are the primary products of the Calvin cycle and are essential for energy storage and structural support. Amino acids, the building blocks of proteins, can also be derived from the intermediates of the Calvin cycle. Lipids, including fats and oils, can be synthesized from the excess carbohydrates produced by the Calvin cycle. Therefore, the correct answer is that organic compounds that can be made from the products of the Calvin cycle include carbohydrates, amino acids, and lipids.

Glycolysis is the initial step in cellular respiration and occurs in the cytosol of the cell. It is a metabolic pathway that breaks down glucose into pyruvate, producing ATP and NADH in the process. This process does not require the presence of oxygen and can occur in both aerobic and anaerobic conditions. The pyruvate produced in glycolysis can then enter the mitochondria for further energy production if oxygen is available, or undergo fermentation if oxygen is absent.

Chlorophyll a is a pigment found in plants that is responsible for absorbing light energy during photosynthesis. It is able to absorb mostly orange-red and blue-violet light, which are the wavelengths that are most effective for driving the process of photosynthesis. This absorption of specific wavelengths allows chlorophyll a to capture energy from sunlight and convert it into chemical energy that can be used by the plant for growth and development.

Glycolysis is the metabolic pathway that breaks down glucose to produce energy in the form of ATP. The efficiency of glycolysis refers to the amount of energy produced relative to the amount of energy available in glucose. The correct answer of 2% implies that only a small fraction of the energy in glucose is converted to ATP through glycolysis. This low efficiency is due to the loss of energy in the form of heat during the process, as well as the production of other byproducts.

The anaerobic pathways refer to metabolic processes that occur without the presence of oxygen. These pathways can provide enough energy to meet the energy needs of many unicellular organisms, such as bacteria and yeast, as well as some multicellular organisms, like certain types of muscle cells. However, it is important to note that not all organisms rely solely on anaerobic pathways for energy production. Some organisms, particularly larger and more complex multicellular organisms, require oxygen and aerobic respiration for their energy needs.

The photosystem and electron transport chains are located in the thylakoid membrane. This is where the light-dependent reactions of photosynthesis occur. The thylakoid membrane is a highly folded membrane inside the chloroplast, which contains the pigments and proteins necessary for capturing light energy and converting it into chemical energy in the form of ATP and NADPH. The photosystems and electron transport chains are embedded in the thylakoid membrane, allowing for the sequential flow of electrons and the generation of a proton gradient, which is essential for the production of ATP.

In the Calvin cycle, for every three molecules of CO2 that enter, the cycle produces six molecules of 3-phosphoglycerate (3-PGA). This is because CO2 molecules are fixed onto a five-carbon molecule called ribulose biphosphate (RuBP) through a series of reactions, resulting in the formation of six molecules of 3-PGA. This molecule is then used in subsequent steps of the cycle to produce glucose and regenerate RuBP. Therefore, 3-PGA is the correct answer as it is directly produced in the Calvin cycle from CO2 fixation.

Pyruvic acid is the correct answer because it is the breakdown product of glucose during glycolysis, which occurs in the cytoplasm of the cell. Pyruvic acid then enters the mitochondrial matrix, where it undergoes further breakdown through a series of reactions known as the Krebs cycle. During the Krebs cycle, pyruvic acid is converted into acetyl CoA, which is then used in the production of ATP through oxidative phosphorylation. Therefore, pyruvic acid is the molecule that diffuses into the mitochondrial matrix for further breakdown.

The maximum efficiency of aerobic respiration refers to the percentage of energy that is converted from glucose into ATP, the energy currency of cells. Aerobic respiration is the most efficient process for generating ATP, and it occurs in the presence of oxygen. While not all of the energy from glucose is converted into ATP, the maximum efficiency achievable is approximately 39%. This means that out of the total energy available in glucose, about 39% can be converted into ATP, while the remaining is lost as heat.

The calving cycle begins when CO2 combines with a five carbon carbohydrate called RuBP. This is because RuBP, or ribulose-1,5-bisphosphate, is an essential molecule in the process of carbon fixation during photosynthesis. It acts as a receptor for CO2 and helps in the initial steps of converting CO2 into organic compounds. Without RuBP, the calving cycle cannot proceed effectively, making it the correct answer. PGA, 3-G3P, and NADPH are also important molecules in photosynthesis, but they do not directly initiate the calving cycle.

Both lactic acid fermentation and alcoholic fermentation produce NAD+ from NADH and H+. During these fermentation processes, NADH is oxidized back to NAD+ by transferring its electrons to H+ ions. This allows NAD+ to be reused in the glycolysis pathway, which is important for the continued production of ATP. Without the conversion of NADH back to NAD+, the glycolysis pathway would become halted due to a lack of available NAD+ molecules. Therefore, the production of NAD+ from NADH and H+ is crucial for the energy production in both lactic acid fermentation and alcoholic fermentation.

C3 and C4 plants differ in terms of the number of carbon atoms in the compound that CO2 is initially incorporated into. In C3 plants, CO2 is initially incorporated into a three-carbon compound called phosphoglyceric acid (PGA). In C4 plants, CO2 is initially incorporated into a four-carbon compound called oxaloacetic acid (OAA). This difference in the initial compound affects the efficiency of carbon fixation and the ability of plants to adapt to different environmental conditions.

During glycolysis, glucose is partially broken down and some of its stored energy is released. Glycolysis is the first step in cellular respiration, where glucose is converted into two molecules of pyruvic acid. This process involves a series of enzymatic reactions that break down glucose into smaller molecules, releasing a small amount of energy in the form of ATP. Although glycolysis does not completely break down glucose, it is an essential step in the production of ATP, which is used as an energy source by the cell.

The correct answer is oxaloacetic acid. Oxaloacetic acid is the starting substance of the Kreb's cycle, also known as the citric acid cycle. It combines with acetyl CoA to form citric acid, which then undergoes a series of reactions to produce energy in the form of ATP. At the end of the cycle, oxaloacetic acid is regenerated, ready to combine with another acetyl CoA molecule and continue the cycle.

As light intensity increases, the rate of photosynthesis initially increases because more light energy is available for the process. However, as the light intensity continues to increase, the rate of photosynthesis levels off because the plant reaches its maximum capacity to utilize the available light energy. This means that after a certain point, increasing the light intensity further does not result in a significant increase in the rate of photosynthesis.

The electron transport chain of aerobic respiration pumps protons into the space between the inner and outer mitochondrial membranes. This is an important step in the process as it creates a proton gradient, which is used to generate ATP through chemiosmosis. The movement of electrons along the electron transport chain drives the pumping of protons across the membrane, creating a higher concentration of protons in the intermembrane space compared to the mitochondrial matrix. This proton gradient is then used by ATP synthase to produce ATP, the energy currency of the cell.

The energy that is used to establish the proton gradient across the thylakoid membrane comes from the splitting of water. During photosynthesis, water molecules are split in a process called photolysis, releasing electrons, protons, and oxygen. The electrons are then used to replenish the electron transport chain of photosystem II, which generates energy and establishes a proton gradient across the thylakoid membrane. This proton gradient is essential for the synthesis of ATP, as well as the production of NADPH, both of which are important energy carriers in photosynthesis.

The Krebs cycle is a series of chemical reactions that occur in the mitochondria of cells. One of the products of the Krebs cycle is the production of two molecules of carbon dioxide (CO2). This occurs when a six carbon molecule is broken down into smaller molecules, resulting in the release of CO2. Therefore, the correct answer is that the Krebs cycle produces two molecules of CO2.

Both photosystem I and photosystem II contain chlorophyll a molecules. Chlorophyll a is a pigment that is essential for photosynthesis as it absorbs light energy. It is responsible for capturing photons and initiating the process of electron transfer in both photosystems. Without chlorophyll a, photosynthesis cannot occur efficiently. Therefore, the presence of chlorophyll a molecules in both photosystem I and photosystem II is crucial for the functioning of the photosynthetic process.

Water participates directly in the light reactions of photosynthesis by donating electrons to photosystem II. In photosystem II, water molecules are split into oxygen, protons, and electrons. The electrons released from water are then transferred to photosystem II, which is a protein complex in the thylakoid membrane of chloroplasts. This donation of electrons is crucial for the generation of ATP and NADPH, which are energy-rich molecules used in the Calvin cycle to produce glucose.