Concept of metabolism - class-XII

Water is the medium for all metabolic processes in living organisms, acting as a solvent for biochemical reactions. While it helps prevent dehydration, its primary biological role is facilitating the chemical reactions that sustain life.

PMA (phorbol myristate acetate) acts as a metabolic activator or tumor promoter, stimulating various cellular processes. It is often described as 'anti-transparent' in the sense of being a metabolic stimulant. CO2 and aspirin have different primary roles in metabolism.

RNA plays a central role in various life processes, including the synthesis of proteins (translation), the processing of pre-mRNA (splicing), and various regulatory metabolic functions. Therefore, all listed processes involve RNA.

The breaking of the C-C bonds of complex compounds through oxidation within the cells, leading to the release of a considerable amount of energy is called as respiration. As carbon-carbon covalent bonds are broken, it is a catabolic process. Respiration involves the synthesis of energy in form of ATP. The synthesis of ATP leads to the formation of several covalent linkages of phosphates. There is synthesis which are included in the anabolic processes.

• Anabolic pathways are those that require energy to synthesize larger molecules. Catabolic pathways are those that generate energy by breaking down larger molecules. Both types of pathways are required for maintaining the cell's energy balance.
  
• Catabolic and anabolic pathway are coupled because catabolic reactions furnish the energy required for anabolism. Catabolic reactions transfer energy from complex molecules to ATP. Anabolic reactions transfer energy from ATP to complex molecules.
• Hence Catabolic and anabolic pathways are often coupled in the cell because the free energy released from one pathway is used to drive other.
• So, the correct answer is 'the free energy released from one pathway is used to drive other'.

Muscle tissue growth is an anabolic process. There is respiration reactions carried out in the muscles which provide energy in the form of ATP. This liberated energy helps the muscles to relax and contract. Thus, the muscles tissue show growth due to anabolic process. 

The catabolic processes are the reactions in which the large complex molecules are broken down to produce smaller organic molecules. The polysaccharide which is a complex molecule is broken down to from many small monosaccharide molecules. For example, glycogen is broken down to produce glucose molecules. 

Catabolism involves the breakdown of a substance, often to release energy or during excretion for removal of waste. Degradation of amino acids in the liver is such an example where amino acids are broken down into inorganic substituents for recycling or removal.

The catabolic processes are the reactions in which the large complex molecules are broken down to produce smaller organic molecules. The polysaccharide which is a complex molecule is broken down to from many small monosaccharide molecules. For example, glycogen is broken down to produce glucose molecules and the process is known as glycogenolysis. 

The nucleotides can be formed by two paths. When the nucleotide is formed due to the breaking of the bonds in the RNA and DNA, this process is an example of a catabolic process. When the nucleotides are formed from the nucleosides and nitrogenous bases, then this is an example of an anabolic process. 

The catabolic processes are the reactions in which the large complex molecules are broken down to form the smaller molecules. The process is an exergonic process in which the energy is released due to the breaking of the bonds of the larger complex molecules. The energy is released due to breaking of the bonds in the ATP molecule to produce ADP or AMP. 

For an 18-carbon fatty acid (stearic acid), beta-oxidation occurs in the mitochondria. The process yields 9 acetyl-CoA, 8 NADH, and 8 FADH2, resulting in a total of 148 ATP molecules after complete oxidation.

• Photosynthesis is the process by which plants, some bacteria, and some protistans use the energy from sunlight to produce glucose from carbon dioxide and water. This glucose can be converted into pyruvate which releases adenosine triphosphate (ATP) by cellular respiration. Oxygen is also formed.
• Anabolic processes are processes that build up compounds. As photosynthesis build up glucose hence it is an anabolic process.
• An endergonic reaction requires or absorbs energy from its surroundings. Photosynthesis is an endergonic reaction. The energy required for photosynthesis comes from light hence endergonic.
  
• Hence Photosynthesis is an example of Anabolism and endergonic reactions.
• So, the correct answer is 'Both A and B'.

In the lac operon model, a repressor protein binds to the operator to block transcription. When an inducer (like lactose) is present, it binds to the repressor, changing its shape so it can no longer bind to the operator, thus activating the gene.

The catabolic processes are the reactions in which the large complex molecules are broken down to form the smaller molecules. The process is an exergonic process in which the energy is released due to the breaking of the bonds of the larger complex molecules. Intracellular digestion refers to the breaking of the larger molecules. Intercellular digestion is the processes in which the molecules are broken down outside the cell and then absorbed. During internal respiration, there is the breakdown of the molecules to produce ATP. 

Enzymes are organic catalysts which aid in facilitating chemical reactions in the body. Each metabolic pathway consists of a series of biochemical reactions that are connected by their intermediates: the products of one reaction are the substrates for subsequent reactions, and so on. Any metabolic pathway inside our body (for example glycolysis) requires several enzymes working in a sequential manner. 

Inulin is an indicator of GFR because, it is neither reabsorbed into the blood after filtration nor secreted through peritubular capillaries, amount of inulin cleared through the urine is indicative of the amount of plasma filtered by body's glomeruli.

Flatworms exhibit regeneration and anabolism/catabolism. Bacteria exhibit anabolism/catabolism and binary fission. Growth by mass and self-consciousness are not universal to these groups in the context of these specific biological definitions.

There are various biochemical reactions taking inside a cell. Some of these reactions may result in absorption of energy (called as endergonic reactions) or release of energy (called as exergonic reactions). Often both these types of reactions are coupled, to get the energy to those endergonic reactions, they are paired up with energy-releasing exergonic reactions (known as coupling reactions). Although, there are a wide variety of reactions taking place inside the body apart from these reactions. Metabolism is a term that is used to describe all these biochemical reactions involved in maintaining the living state of the cells and the organism.