Human Physiology - Cell structure and function
This attachment of a phosphate group to the carrier molecule causes a conformational change in (or a change in the shape of ) the protein so that a channel opens between the inside and outside of the cell membrane. Then, on the inside of the cell, ATP (Adenosine TriPhosphate) binds to another site on the carrier and phosphorylates (adds one of its phospate groups, or -PO4, to) one of the amino acids that is part of the carrier molecule
Specialized Cell Structure and Function: Cellular Respiration
The mechanism of the electron transport chain can be described in five steps: High-energy electrons from NADH and FADH2 enter the electron transport chain and are passed from molecule to molecule, losing energy in a controlled stepwise manner. The process of glycolysis is an enzyme controlled, four-step reaction that occurs in the cytoplasm of the cells: Energy is required to begin the process, so a molecule of glucose accepts two high-energy phosphate groups from two ATP molecules
First ATP bonds are broken, so that we are left with ADP + Pi, which releases energy; however, most of the energy stays with the broken-off phosphate, which we can then bond to the molecule that needs the energy. If you run a marathon, or jog for that matter, you use the oxygen you inhale to operate in these aerobic metabolic pathways to provide the energy your muscles need to contract
Plants can also produce ATP in this manner in their mitochondria but plants can also produce ATP by using the energy of sunlight in chloroplasts as discussed later. Now that scientists understand how some of these highly organized molecules function and why they are required for life, their origin must be explained
Aerobic Cellular Respiration
The objective in this process is to break down glucose and form ATP, NADH and pyruvates (pyruvates or pyruvic acid is the end product of glycolysis, which can be converted to different biomolecules). A point worth mentioning here is, while glycolysis takes place in the cytoplasm of a cell, the Krebs Cycle and electron transport takes place in the mitochondria of a cell
Plant Energy Transductions III
Instead, if oxygen is not available, certain organisms like yeasts, and lactate bacteria use pyruvate and produce ethanol and lactate respectively by intramolecular biological oxidation
Cell respiration - definition of cell respiration by Medical dictionary
It is not lack of oxygen but excess of carbon dioxide that causes this instant and powerful reaction.The carbon dioxide tension (Pco2), of arterial blood normally is 35 to 45 mm Hg. the metabolic processes by which living cells break down carbohydrates, amino acids, and fats to produce energy in the form of adenosine triphosphate (ATP); called also cell respiration.The Respiratory Sequence
The electron transport system transfers protons from the inner compartment to the outer; as the protons flow back to the inner compartment, the energy of their movement is used to add phosphate to ADP, forming ATP. Water flows across the respiratory surface of the gill in one direction while blood flows in the other direction through the blood vessels on the other side of the surface
In this reaction, the same total free energy is released as in stepwise oxidation, but none is stored in carrier molecules, so most of it will be lost as heat (free energy). Enzymes do not force a reaction to proceed if it wouldn't do so without the catalyst; rather, they simply lower the energy barrier required for the reaction to begin (Figure 4)
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Cellular Respiration:
In some ways similar to the chloroplast, the mitochondria also has two main sites for the reactions: The matrix, a liquidy part of the mitochondrion, and the christae, the folded membranes in the mitochondrion. In our cells, anaerobic respiration results in the production of lactic acid, the molecule that builds up when you 'feel the burn' during or after strenuous exercise
Cells -Cell Respiration
most enzyme names end in -ase enzymes lower the energy needed to start a chemical reaction (activation energy), thus speeding the reaction How do enzymes work? substrate: molecules upon which an enzyme acts. Enzyme Structure and Function catalyst: inorganic or organic substance which speeds up the rate of a chemical reaction without entering the reaction itself
Cell Respiration: Introduction
Since most textbooks provide abundant details of the chemical reactions in respiration, this tutorial will focus on how the chemical energy in glucose is converted into ATP and where respiration occurs in the cell. Carbohydrates, fats, and proteins can all be used as fuels in cellular respiration, but glucose is most commonly used as an example to examine the reactions and pathways involved
A series of metabolic pathways (the Krebs cycle and others) in the mitochondria result in the further breaking of chemical bonds and the liberation of ATP. Immediately after exposure to 14CO2, the plant's photosynthetic tissue is killed by immersing it in boiling alcohol, and all of the biochemical reactions cease
Cellular Respiration
Because there are a number of enzymes and steps involved in forming porphyrin rings, there are a number of possible points in the process where genetic defects could occur. Out of many possible types of fermentation processes, two of the most common types are lactic acid fermentation and alcohol fermentation (other types of fermentation such as methanol fermentation and acetone fermentation also exist)
Catalysis and the Use of Energy by Cells - Molecular Biology of the Cell - NCBI Bookshelf
The principle is exactly the same, in that the OH group that will be removed in the condensation reaction is first activated by becoming involved in a high-energy linkage to a second molecule. Plants, animals, and microorganisms have existed together on this planet for so long that many of them have become an essential part of the others' environments
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