Human physiology chapter 3, cell metabolism Flashcards
define cell metabolism
- the sum of all chemical reactions occurring in a cell
define energy metabolism
reactions involved in energy storage and use
define catabolic
- breakdown of larger molecules into smaller molecules
define anabolic reactions
synthesis of larger molecules from smaller reactants
Define hydrolysis and its formal
- reactant side: breaks bonds sing H20
formula: A-B + H20 = A-OH + H-B
(Eg. sucrose + h20 = glucose + fructose)
define condensation and its formula
- product side: make new bonds - releasing H20
A-OH + H-B = A-B + H20
(eg: glucose + fructose = sucrose + H20)
define phosphorylation and its formula.
- adding phosphate group (+Pi)
- reactant side: adding inorganic phosphorous)
A + Pi = A-P
(eg: ADP + Pi = ATP + H20)
Define dephosphorylation and it’s formula
- removing a phosphate group (-Pi)
- product side: releasing inorganic phosphorous
A-P = A + Pi
(eg: ATP = H20 = ADP + Pi (also a hydrolysis reaction)
what is a oxidation reduction reaction?
- oxidation = loss of electrons
- removal of electrons:
A* + B AB*
where * is an electron
A is oxidized (loses electron)
B is reduced (gains electron)
- removal of electrons:
What is ATP synthesis
- ADP + Pi + energy → ATP (+ H2O)
- A condensation reaction
- A phosphorylation reaction
what is a EXERGONIC REACTION
- energy is released
what is glucose oxidation?
- the central reaction of energy metabolism
- ΔE = –686 kcal/mole
how much energy is released durring glucose oxidation
= 686 kcal
what are the 4 stages of glucose oxidation?
- glycolysis
- Krebs cycle
- oxidative phosphorylation
- electraon transport chain
what is glycolysis?
- breakdown of glucose to 2 pyruvate molecules
- sequence of 10 enzyme - catalyzed reactions that take place in the cytosol
- naet gain of 2 ATP moleucles
How does glycolysis get linked to the Kerbs cycle?
- pyruvate get converted to acetyl CoA
- unidirectional
what is the Krebs cycle?
- the sequence of reactions by which most living cells generate energy during the process of aerobic respiration. It takes place in the mitochondria, consuming oxygen, producing carbon dioxide and water as waste products, and converting ADP to energy-rich ATP.
what is the first step of the Krebs cycle?
- Acetyl-CoA Formation: The cycle begins when a molecule called acetyl-CoA combines with a four-carbon molecule called oxaloacetate to form a six-carbon molecule called citrate. This step is catalyzed by the enzyme citrate synthase.
What is the second step of the krebs cycle?
Isomerization: Citrate undergoes a series of rearrangements and isomerizations to form its isomer, isocitrate. This step is catalyzed by the enzyme aconitase.
what is the third step of the krebs cycle?
Alpha-Ketoglutarate Formation: Isocitrate is then oxidized to form alpha-ketoglutarate, releasing carbon dioxide and reducing the coenzyme NAD+ to NADH. This step is catalyzed by the enzyme isocitrate dehydrogenase.
what is the fourth step of the Krebs cycle?
Succinyl-CoA Formation: Alpha-ketoglutarate is oxidized to form succinyl-CoA, releasing another molecule of carbon dioxide and reducing NAD+ to NADH. This step is catalyzed by the enzyme alpha-ketoglutarate dehydrogenase complex.
what is the fifth step of the Krebs cycle?
Succinate Formation: Succinyl-CoA is then converted into succinate while transferring a phosphate group to GDP, forming GTP (which can later be converted into ATP). This step is catalyzed by the enzyme succinyl-CoA synthetase
what is the sixth step of the Krebs cycle?
Fumarate Formation: Succinate is oxidized to form fumarate, reducing FAD to FADH2. This step is catalyzed by the enzyme succinate dehydrogenase, which is unique because it is bound to the inner mitochondrial membrane and participates in both the Krebs cycle and the electron transport chain.
