Biochemistry Quiz: Tissue Respiration & Cycle

A site on an enzyme molecule where substances that differ in structure from substrates bind, influencing enzyme activity.

Substances that reduce the rate of enzyme reactions by interacting with the enzyme.

The process of breaking down complex substances into simpler ones, releasing energy.

The process of building complex molecules from simpler ones, using energy.

A property of enzymes where they can interact with specific molecules (substrates) to catalyze reactions.

Vitamins that act as coenzymes, assisting in metabolic reactions.

A derivative of vitamin PP (niacin) is involved in dehydrogenation reactions, which involve the removal of hydrogen atoms from molecules.

A derivative of thiamine (vitamin B1) is crucial for oxidative decarboxylation of keto acids, which involves the removal of carbon dioxide and hydrogen.

The combined process of tissue respiration and oxidative phosphorylation, where energy from nutrient breakdown is used to generate ATP.

When the coupling between tissue respiration and oxidative phosphorylation is disrupted, less energy is used to make ATP, causing more energy to be released as heat. This can lead to overheating.

Uncoupling of tissue respiration and oxidative phosphorylation. Without the electrochemical potential, the synthesis of ATP stops and the cell can't use energy efficiently.

Increased ADP (adenosine diphosphate) levels signal a need for more ATP. This stimulates both tissue respiration and oxidative phosphorylation to produce more ATP.

The Krebs cycle sees the decarboxylation of isocitrate and alpha-ketoglutarate, releasing carbon dioxide and producing NADH and FADH2, which are important for ATP synthesis.

Increased ADP levels stimulate the activity of the citrate cycle. This is because ADP signals the need for more ATP, which is generated by the citrate cycle.

The oxidation of one molecule of acetyl-CoA in the tricarboxylic acid cycle (Krebs cycle) generates one ATP molecule through substrate-level phosphorylation. This is a small amount compared to the ATP produced via oxidative phosphorylation.

Cocarboxylase activates the oxidative decarboxylation of pyruvate, a crucial step in cellular respiration. This process helps improve energy supply by increasing the production of acetyl-CoA, which fuels the Krebs cycle.

Barbiturates are a class of drugs that act as central nervous system depressants, reducing the activity of the brain and body, especially in the brainstem where they inhibit neuronal activity. Their effect is thought to be a consequence of their ability to bind to specific sites on the GABA-A receptor, which then increase the affinity of the receptor for GABA, a neurotransmitter that inhibits nerve impulses, thus leading to enhanced GABAergic signaling in the brain. This enhanced GABAergic signaling further reduces anxiety, insomnia, and seizures, and promotes relaxation.

NAD+ (Nicotinamide adenine dinucleotide) is a critical coenzyme involved in the second stage of glycolysis. It acts as an electron acceptor during the oxidation of glyceraldehyde 3-phosphate, becoming reduced to NADH. This NADH carries the electrons, and ultimately the energy, to the electron transport chain to generate ATP, a key energy currency for cellular processes.

Aerobic glycolysis, the breakdown of glucose in the presence of oxygen, yields a net of 8 ATP molecules per glucose molecule. However, this comes from two cycles of glycolysis, each yielding 4 ATP molecules. Each glucose molecule is initially broken down into two pyruvate molecules, which then undergo subsequent oxidation to create the energy.

During oxidative decarboxylation of pyruvate, a key step in cellular respiration, 3 molecules of ATP are synthesized. This process converts pyruvate to acetyl-CoA, a molecule crucial for entering the Krebs cycle, where further energy is extracted.

The energetic yield from pyruvate oxidation per molecule in the common pathway of catabolism is 15 moles of ATP. This is the net energy produced when pyruvate undergoes the reactions leading to the production of acetyl-CoA and its subsequent breakdown in the Krebs cycle.

Anaerobic glycolysis, the breakdown of glucose without oxygen, generates only 2 ATP molecules per 1 mole of glucose. This inefficient pathway is a backup for when oxygen is limited, but it produces lactic acid as a byproduct, potentially causing lactic acidosis.

In pathological conditions, a disruption in oxygen supply to tissues (hypoxia) can lead to lactic acidosis. This occurs because cells rely on anaerobic glycolysis for energy production, leading to the accumulation of lactic acid, lowering blood pH.

ADP (adenosine diphosphate) plays a vital role in regulating glycolysis. Its accumulation indicates a high demand for ATP, signaling the need to increase glycolysis to generate more energy. This feedback mechanism ensures the cell can meet its energy needs.

The process of maintaining a stable internal body temperature despite external fluctuations. This involves mechanisms like sweating, shivering, and adjusting blood flow.

The amount of energy required to maintain basic bodily functions at rest, including breathing, heartbeat, and brain activity.

The increase in metabolic rate that occurs after consuming food. This energy is used for digesting, absorbing, and processing nutrients.

The process of breaking down stored fats to release energy. This is often activated during periods of fasting or intense physical activity.

The process of building glycogen from glucose. This occurs when blood sugar levels are high, storing excess glucose for later use.

The primary hormone responsible for increasing heat production in the body. It influences metabolic rate and energy expenditure.

The rate at which energy is expended during physical activity, often measured in metabolic equivalents (METs).

The transfer of heat through direct contact between objects of different temperatures.

The transfer of heat through electromagnetic radiation, like infrared waves.

The transfer of heat through the movement of fluids (liquids or gases).

The process of liquid turning into vapor, taking heat with it.

The receptors responsible for sensing cold temperatures, located in the skin's deeper layers.

The receptors responsible for sensing hot temperatures, located in the skin's surface layers.

The process of breaking down proteins into simpler molecules, primarily urea, uric acid, creatinine, and indican.

The caloric coefficient of carbohydrates is the amount of energy released when one gram of carbohydrates is burned. It is measured in kilocalories (kcal). The typical value for carbohydrates is 4.1 kcal/g.

The caloric coefficient of fats is the number of kilocalories (kcal) released when one gram of fat is burned in the body. It is typically 9.3 kcal/g.

The body's temperature fluctuates naturally throughout the day, with the lowest point typically occurring between 03-04 am.

Direct calorimetry is a method for measuring the amount of heat produced by the body. This is done by placing the individual in a sealed chamber where heat output can be accurately measured.

Indirect calorimetry measures oxygen consumption and carbon dioxide production to estimate energy expenditure. This method indirectly calculates the amount of heat produced by the body based on the oxygen used and carbon dioxide released during respiration.

A positive nitrogen balance indicates that the body is retaining more nitrogen than it is losing. This occurs when the body is building more tissues, such as during growth or pregnancy, as protein synthesis requires nitrogen.

Acidic urine can be caused by various factors, including physical activity, consuming meat-based foods, and certain medical conditions.

Deviation of the level of basic metabolism from the norm can be caused by hyperthyroidism, a condition where the thyroid gland produces an excessive amount of thyroid hormones. Hyperthyroidism can lead to increased metabolism, resulting in symptoms like palpitations, sweating, irritability, and weight loss.