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Respiration is one of the key ways a cell releases chemical energy to fuel cellular activity. The overall reaction occurs in a series of biochemical steps, some of which are redox reactions. Although cellular respiration is technically a combustion reaction , it is an unusual one because of the slow, controlled release of energy from the series ...
Although all chemical reactions are technically reversible, conditions in the cell are often such that it is thermodynamically more favorable for flux to proceed in one direction of a reaction. [8] For example, one pathway may be responsible for the synthesis of a particular amino acid, but the breakdown of that amino acid may occur via a ...
The chain of redox reactions driving the flow of electrons through the electron transport chain, from electron donors such as NADH to electron acceptors such as oxygen and hydrogen (protons), is an exergonic process – it releases energy, whereas the synthesis of ATP is an endergonic process, which requires an input of energy.
Metabolism (/ m ə ˈ t æ b ə l ɪ z ə m /, from Greek: μεταβολή metabolē, "change") is the set of life-sustaining chemical reactions in organisms.The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the conversion of food to building blocks of proteins, lipids, nucleic acids, and some carbohydrates; and the ...
In mammals, physiological respiration involves respiratory cycles of inhaled and exhaled breaths. Inhalation (breathing in) is usually an active movement that brings air into the lungs where the process of gas exchange takes place between the air in the alveoli and the blood in the pulmonary capillaries.
The energy created from one ion moving down its electrochemical gradient is used to power the transport of another ion moving against its electrochemical gradient. [9] This involves pore-forming proteins that form channels across the cell membrane. The difference between passive transport and active transport is that the active transport ...
Transcytosis is the movement of large molecules across the interior of a cell. This process occurs by engulfing the molecule as it moves across the interior of the cell and then releasing the molecule on the other side. There are two types of transcytosis are receptor-mediated transcytosis (RMT) and adsorptive-mediated transcytosis (AMT).
This reaction occurs due to the enzyme hexokinase, an enzyme that helps phosphorylate many six-membered ring structures. Phosphorylation takes place in step 3, where fructose-6-phosphate is converted to fructose 1,6-bisphosphate. This reaction is catalyzed by phosphofructokinase.