Cellular Respiration and Metabolism

Flashcards for vocabulary review.

Cellular Respiration and Intermediate Metabolism

The set of enzymatic reactions by which the cell can survive, exchanging matter and energy with its surroundings to subsist, grow, and multiply.

Anabolism

Synthesizing complex substances (macromolecules) from simple substances (monomers), consuming energy. Example: From glucose to glycogen.

Catabolism

Forming simple substances from complex substances, releasing energy. It produces energy that the anabolic phase utilizes.

Intermediate Metabolites

Products of the different reactions that constitute metabolic sequences, used either to continue a sequence or to connect metabolisms at a bifurcation point.

Metabolites of Continuity

A metabolite that serves to continue the metabolic pathway.

Metabolites of Crossroads

Metabolites found at a branching point in the sequence, serving to connect metabolisms.

Phototrophic Cells

Cells that obtain energy from sunlight (e.g., plants).

Chemotrophic Cells

Cells that obtain energy from chemical reactions (e.g., higher animals).

Microergic

Generate less than 7.3 KCAL/G. Example: Glucose 1 phosphate

Macroergic

Generate equal to or more than 7.3 KCAL/G. ATP = 7.3 KCAL/G.

ATP (Adenosine Triphosphate)

A triphosphorylated nucleotide composed of adenine, ribose, and 3 phosphate groups; it is the primary energy-donating molecule in biological systems.

Endergonic Processes

Processes that require or consume energy.

Insulin

Hormone that promotes energy storage and is anabolic for synthesis of glycogen, triglycerides, proteins, nucleic acids, etc. Secreted by beta cells of the Islets of Langerhans.

Glucagon

Hormone that counter-regulates insulin, stimulating glucose synthesis and degrading glycogen in response to hypoglycemia. Secreted by alpha cells of the Islets of Langerhans.

Allosteric Modifiers

Regulate enzyme activity by binding to allosteric sites, modifying the active center to stimulate or inhibit a process based on metabolic needs.

Genetic Control

Control of metabolic pathways through the regulation of gene expression, affecting the synthesis of enzymes like insulin/glucagon.

Covalent Modification

Control mechanism involving phosphorylation (by glucagon) and dephosphorylation (by insulin) to regulate enzyme activity.

Cellular Respiration

The set of molecular processes that consume O2 and form CO2 in cells, occurring in the mitochondrial matrix.

Krebs Cycle

Central and final route of degradation of glucides, lipids, and amino acids in aerobic cells, localized in the mitochondrial matrix, feeding Acetyl-CoA and producing CO2 + H2 + ATP; an amphibolic cycle.

Production of Acetyl-CoA

Mainly from glucose -> Pyruvate -> Acetyl-CoA, located in the mitochondrial matrix, with the enzyme complex Pyruvate Dehydrogenase (PDC).

Respiratory Chain or Electron Transport Chain

A series of REDOX reactions where electrons are transported to O2 (the final acceptor), located in the inner mitochondrial membrane, fed by H2 transported by NADH + H/FADH2, and producing H2O.

Oxidative Phosphorylation (FOSOX)

Synthesis of ATP coupled to the electron transport chain in the inner mitochondrial membrane, dependent on the energy produced in the ETC.

Chemiosmotic Theory

Peter Mitchell's theory explaining ATP synthesis, requiring an intact inner mitochondrial membrane impermeable to protons, an electrochemical gradient or proton-motive force, respiratory chain complexes as proton pumps, and ATP synthase to form ATP.

Mitochondrial Myopathies

Group of myopathies characterized by a lack of energy, causing weakness, cramps, fatigue with light exertion, and muscle atrophy, often related to mitochondrial DNA with maternal inheritance.

Leigh Syndrome

A genetically determined nuclear or mitochondrial disorder of sporadic appearance with variable inheritance, producing a deficit of the Pyruvate-dehydrogenase complex and/or complexes I-IV of the mitochondrial respiratory chain, affecting various organs and characterized by seizures, psychomotor delay, optic atrophy, hypotonia, weakness, lethargy, vomiting, abnormal movements, and respiratory abnormalities.

Inhibitors of the Electron Transport Chain

Substances that inhibit the flow of electrons through the ETC, reducing O2 consumption, increasing NADH/NAD+ and FADH2/FAD ratios, and decreasing ATP production.

Inhibitors of FOSOX

Substances that inhibit ATP Synthase (V complex).

Uncoupling Substances

Substances that prevent FOSOX, increasing the velocity of the ETC and releasing energy as heat.

Anaplerotic Reactions / Anaplerosis

Reactions that feed the CK, produce intermediate metabolites of the cycle favoring the degradation of Acetyl-CoA, drain intermediate metabolites of the cycle for participation in biosynthetic processes, and contribute to dynamic balance.

Reactive Oxygen Species (ROS)

Partial reduction products of O2 that are unstable and involved in cellular damage by reacting rapidly with lipids (peroxidation) and proteins (denaturation).

Cytochrome P450

Enzymes present in the RER (active in liver, intestine, lung, kidney, and brain), containing a heme group, associated with NADPH Cit P450 reductase, constituting the main source of free radicals, and catalyzing reactions where an electron from O2 is transferred to an organic substrate, with functions in steroid biosynthesis, prostaglandin synthesis, AA degradation, and biotransformation of hydrophobic materials.

Digestion of Glucides

Enzymes (glycosidases) responsible for the digestion of sugars, starting in the mouth (ptyalin or a-amylase) and continuing in the small intestine (a-amylase and disaccharidases).

Sodium Cotransport

Active transport depending on Na+ transport, used for absorption of sugars from low to high concentration.

Independent of Sodium

Facilitated diffusion independent of Sodium: GLUT

GLUT

Glucose transporters that vary in distribution, hormonal sensitivity, and affinity for sugar.

GLUT 2

High Km, stimulated postprandially; involved in glycogenesis stimulattion.

GLUT 4

Low Km, stimulated only with isnsulin present; involved in glycolysis and glycogenesis

GLUT 1

Low Km, high affinity.

Hexokinase and Glucokinase

Enzymes that depend on Mg2+ as a cofactor and are used to activate monosaccharides by uniting them with a phosphate group.

Hexokinase

Low Km (0.05 mM) Found in red blood cells.

Glucoquinasa

High Km (15 mM), found in liver.

Glycolysis

Oxidation of glucose to obtain pyruvic or lactic acid.

Glucogenesis

Synthesis pathway of glucogenesis.

Pentose Phosphate Pathway

Special pathway where sugars of different carbons and NADPH are synthesized.

Gluconeogenesis

Pathway for synthesis of new glucose from non-carbohydrate substances.

Glucogenolysis

Process in which liver glycogen is broken down.

Glycolysis

Oxidation of glucose, occurring in the cytosol and producing pyruvate in aerobic conditions or lactate in anaerobic conditions, generating ATP and NADH.

Pyruvate Kinase Deficiency

The 2nd most common genetic deficiency causing hemolytic anemia, characterized by chronic hemolysis, increased 2,3-Di-Phospho-Glycerate, and absence of Heinz bodies; resulting in decreased ATP and altered red blood cell shape.

Aerobic Glycolysis

Degradation of glucose to CO2, H2O, and ATP.

Anaerobic Glycolysis

Degradation of glucose to lactate and ATP.

NADH

Use of Glicerol-3-Phosphate or Malate to arrive the NADH DHasa

Lactate

Utilizing Lactate to form glucose with gluconeogenesis.

The Fructoquinasa absence

Deficiency when the hexokinase takes over.

Deficiency F1-P Aldolasa

Severe pathological condition with the accumulation of F1-P in liver and proximal renal tubules.

Galactosemia

Genetic condition resulting in early cataracts, vomiting, diarrhea from lactose ingestion, lethargy, liver damage, hyperbilirubinemia, and mental retardation.

Pentose Pathway

Direct oxidation of glucose with the release of NADPH + H+ and CO2 in the cytoplasm, involving an oxidative phase (formation of Ribulose 5P) and a non-oxidative phase (interconversion of monosaccharides), producing NADPH + H for synthesis of fatty acids, nucleotides, cholesterol, and other steroids, and Ribose 5P for nucleotide synthesis.

Anabolic

Biosynthesis of AA, etc…

Favism

Deficit of the G6P Dhasa which produce oxidative Estres which produce H2O2.

The insulin and glucagon

For control in glycemia.

Glucogenina

Protein needed to the sintesis of glucogen.

Glucogenesis

Synthesis of glycogen from glucose. Mainly in the liver and muscles.

UDP-Glucose

Reactions where the elongations of glucogenic chains.

Glucogenolysis

Degrading of glucogen to become glucose.

Glucógeno Fosforilasa

Catalizes the rompimiento of enalces by fosforólisis, that libérate glucose

Hepatic Glucógeno

Is the almacén to maintein the [glucose] during the fasting periods.

Es<mular la degradación de glucógeno

The insulin ha hecho que baje AMPc.

Glucogenósis Tipo I (Von Gierke)

The G6 Fosfatasa that is deficiente who can't remove the G6P.

Gluconeogenesis

Síntesis de nueva glucosa a par%r de sustancias que no son carbohidratos

The Alanina

AA muy ac%vo en la gluconeogénesis a par%r de los AA