02.06 Cellular Respiration
NADH/NAD+
NADH - Gain electrons (reduced) NAD+. - Lose electrons= oxidized.
Oxaloacetate
A four-carbon molecule that binds with the two-carbon acetyl unit of acetyl-CoA to form citric acid in the first step of the Krebs cycle.
What is the relationship between the reactants and products in cellular respiration?
According to both models, glucose and six oxygen molecules are reactants used by the process of cellular respiration. They produce six carbon dioxide molecules and six water molecules. The model at the top of the page also shows that carbon dioxide and water (plus sunlight) have the same relationship with sugar and oxygen in the chloroplast, except the reactants and products are switched in a process called photosynthesis
Explain why cellular respiration releases more energy than it uses.
According to the glycolysis model, the energy of two ATP is used to break the bonds in glucose to form pyruvate. However, breaking the bonds also releases energy to form 2 NADH and 4 ATP. In the Krebs cycle, additional NADH, ATP, and FADH2 are made. The model of the electron transport chain (ETC) shows NADH and FADH2 used to facilitate the process. However, the ETC makes 30 ATP molecules. Therefore, the process of cellular respiration releases more energy than it uses because the energy released in the form of ATP is greater than the energy required to break the bonds of sugar and oxygen.
Explain how matter and energy are conserved during cellular respiration.
According to the models, cellular respiration releases energy as carbon, hydrogen, and oxygen are rearranged. The existing chemical bonds are broken and new chemical bonds are formed, but matter and energy are neither created nor destroyed. Cellular respiration converts glucose to useable cell energy to sustain life's processes.
Acetyl CoA
Acetyl coenzyme A; the entry compound for the citric acid cycle in cellular respiration, formed from a fragment of pyruvate attached to a coenzyme.
What is aerobic respiration?
Aerobic respiration uses oxygen from the air to release energy from glucose.
What is the reaction for cellular respiration?
C 6 H 12 O 6 + 6 O 2 --> 6 CO 2 + 6 H 2 O + ATP is the complete balanced chemical formula for cellular respiration.
What is used to process fuel in cellular respiration?
Carbohydrates, fats, and proteins can be processed as fuel in cellular respiration. Let's explore the steps of this process by following the breakdown of glucose (C6H12O6). C6H12O6 + 6O2→ 6CO2 + 6H2O + Energy (ATP and Heat)
What are the products of cellular respiration
Carbon Dioxide (CO2): A product given off during cellular respiration, containing the carbon atoms from the glucose molecule. The carbon dioxide gas that is released during cellular respiration can be used as a reactant for photosynthesis. Water (H2O): At the end of the electron transport chain, electrons, hydrogen ions, and oxygen bond together to form water molecules.
What is cellular respiration? What is produced?
Cellular respiration is a process that uses oxygen to harvest the chemical energy stored in organic molecules. Carbon dioxide is produced as the chemical energy is released from the organic molecules. The reaction below describes this process: C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy
How are ATP molecules made during cellular respiration?
Cellular respiration is more common because it is more efficient, forming more ATP from each organic molecule. It is a multistep process but can be summarized as follows: Organic Compounds + Oxygen → Carbon Dioxide + Water + Energy During aerobic cellular respiration, glucose reacts with oxygen, forming ATP that can be used by the cell. Carbon dioxide and water are created as byproducts. The overall equation for aerobic cellular respiration is: In cellular respiration, glucose and oxygen react to form ATP.
What types of organisms take in oxygen?
Cellular respiration takes place in the cells of animals, plants, and fungi, and also in algae and other protists. It is often called aerobic respiration because the process requires oxygen (the root aer comes from the Greek word for "air").
What are the reactants of cellular respiration?
Glucose (C6H12O6): An organic compound found in many foods. It will be broken down into smaller carbon-based compounds, such as pyruvate and citric acid, as energy is released. Oxygen (O2): A reactant required for this process to occur (this is why cellular respiration is called an aerobic process).
What are the important things to remember about electron transport chain?
Important things to remember about the electron transport chain: It produces significantly more ATP than any other stage of cellular respiration. It uses the high-energy electrons stored in NADH and FADH2. It occurs at the inner membrane of the mitochondria. It requires oxygen, and that oxygen is used to make water molecules. It reforms NAD+ and FAD, which are sent back to participate in earlier stages of respiration.
Identify the break down and formation of chemical bonds that occur during cellular respiration.
In the glycolysis model, 6-carbon glucose is broken down into two 3-carbon molecules called pyruvate. In the Krebs cycle model, the bonds between carbons are broken within the pyruvate molecules. Bonds between carbon and oxygen are formed to make carbon dioxide. In the electron transport model, hydrogens are bonded to oxygen to make water.
What are the important things to remember about glycolysis?
It is part of both aerobic and anaerobic respiration. It splits glucose, a 6-carbon compound, into two 3-carbon pyruvate molecules. It uses two ATP molecules but ends up forming four ATP molecules. This gives a net gain of two ATP molecules. It takes place in the cytoplasm of the cell. It does not require oxygen.
lactic acid fermentation
Most animals and other organisms, such as fungi and bacteria, undergo lactic acid fermentation when oxygen is not available. This process converts pyruvate to lactic acid. Sometimes when you exercise, your muscles use up oxygen faster than you can breathe to replenish. Your muscle cells switch to use anaerobic respiration. This is why you may feel your muscles "burn" from the buildup of lactic acid. Lactic acid can cause muscle fatigue or pain, but it is eventually carried off to the liver to be converted back to pyruvate.
What are the electron carriers of cellular respiration?
NAD+ and NADH: NAD+ is an electron carrier that accepts a pair of high-energy electrons to become NADH. The NADH carries the high-energy electrons to the electron transport chain where they are used to build high-powered ATP molecules. FAD and FADH2: FAD is another electron carrier. It accepts a pair of high-energy electrons to form FADH2, which carries high-energy electrons to the electron transport chain.
electron transport chain:
The electron transport chain is made up of three protein pumps embedded in the inner membrane of the mitochondrion. The NADH and FADH2 formed in the first two steps of cellular respiration transfer the high-energy electrons to these protein pumps. Energy is released as the electrons are transferred through the chain of proteins. That energy is used to move positive hydrogen ions (H+) from the mitochondrion's matrix (the space inside the inner membrane) to the intermembrane space between the two membranes. The greater concentration of hydrogen ions in the intermembrane space causes hydrogen ions to diffuse back into the matrix through a protein called an ATP synthase. The ATP synthase is able to use the diffusion of hydrogen ions to build ATP molecules. The flow of ions through the ATP synthase channel produces around 34 ATP molecules. At the end of the electron transport chain, the electrons combine with hydrogen ions and oxygen to form water molecules. The NAD+ and FAD molecules are sent back to the cytoplasm and mitochondrial matrix to participate in future rounds of glycolysis and the Krebs cycle.
What happens during the first two stages of cellular respiration?
The first two stages of cellular respiration, glycolysis and the Krebs cycle, are responsible for breaking down organic molecules, like glucose. These stages produce ATP molecules and donate high-energy electrons that are important for the third stage of the process, the electron transport chain. In the electron transport chain, the high-energy electrons of the first two stages assist in the production of more ATP. It is during this third stage that the bulk of ATP molecules are formed for the cell.
How is glucose broken down in cellular respiration?
The glucose is broken down first through the anaerobic process of glycolysis, leading to the production of some ATP and pyruvate end-product. In anaerobic conditions, pyruvate converts to lactate through reduction.
How are organic molecules in food used for energy?
The organic molecules in food contain stored energy that is released when their chemical bonds are broken. During cellular respiration, high-energy electrons are harvested from organic molecules and used to make adenosine triphosphate (ATP) molecules. ATP provides energy for most work done by the cell.
What is fermentation and when does it occur?
When there is a limited supply of oxygen, cellular respiration cannot proceed. Glycolysis can still occur without oxygen, but it would be followed by an anaerobic reaction called fermentation.
alcoholic fermentation
Yeast and other microorganisms undergo anaerobic alcoholic fermentation. This process produces ethyl alcohol and carbon dioxide. This is used to make dough rise and to make alcoholic beverages.
What are the two types of respiration?
aerobic and anaerobic
Glycolysis
glycolysis is anaerobic (does not require oxygen) and occurs in the cytoplasm Glycolysis is the first stage of cellular respiration. During this process, a six-carbon glucose molecule is broken down into two separate three-carbon molecules called pyruvate. These pyruvate molecules are carried into the cell's mitochondrion to be used as reactants in the Krebs cycle. Glycolysis uses energy from two ATP molecules to get started but ends up producing four ATP molecules. This means there is a net gain of two ATP molecules for each molecule of glucose that is broken down in this stage of cellular respiration. For each molecule of glucose processed in glycolysis, two pairs of high-energy electrons are released. Each NAD+ molecule accepts an electron pair, forming two NADH molecules. These electron carriers transport the high-energy electrons into the mitochondrion to be used in the third stage of cellular respiration, the electron transport chain.
What are the three stages of cellular respiration?
glycolysis, krebs cycle, electron transport chain The first two stages of cellular respiration, glycolysis and the Krebs cycle, are responsible for breaking down organic molecules, like glucose. These stages produce ATP molecules and donate high-energy electrons that are important for the third stage of the process, the electron transport chain. In the electron transport chain, the high-energy electrons of the first two stages assist in the production of more ATP. It is during this third stage that the bulk of ATP molecules are formed for the cell.
What is the purpose of cellular respiration?
make ATP
What are the important things to remember about Krebs cycle?
t is important to remember that each glucose molecule is split into two pyruvate molecules, which are converted into the acetyl-CoA that move through the Krebs cycle. This means that for each glucose molecule that originally enters cellular respiration, the Krebs cycle runs twice (once for each acetyl-CoA molecule). This equation summarizes what happens when the two acetyl-CoA molecules go through the Krebs cycle: 2 acetyl-CoA + 2 oxaloacetate → 4 CO2 + 2 oxaloacetate + 6 NADH + 2 FADH2 + 2 ATP Important things to remember about the Krebs cycle: Pyruvate is broken down into a two-carbon compound before entering the Krebs cycle, releasing one CO2 molecule. It forms two more CO2 molecules for each turn of the Krebs cycle. It produces two ATP molecules for each turn of the Krebs cycle. It sends energy-rich NADH and FADH2 molecules to the electron transport chain, but it does not send any carbon compounds on to the next stage. It occurs in the mitochondrial matrix. It does not directly use oxygen, but it can only occur when oxygen is present. This means it is considered an aerobic process.
Adenosine Triphosphate (ATP)
三磷酸腺苷
Pyruvate, Citric Acid
丙酮酸和檸檬酸
ethyl alcohol (electrons acceptor)
乙醇
cleave off
劈開
derivative
衍生物
