Test: Concept of Metabolism, Metabolic Basis & The Living State - Grade 12 MCQ

• Those metabolites that are formed during growth phase as a result of energy metabolism are called primary metabolites.
• They play a vital role in the growth, development and reproduction.

Anabolic pathways require an input of energy to synthesize complex molecules from simpler ones.
Example: Synthesis of large proteins from amino acid building blocks, and the synthesis of new DNA strands from nucleic acid building blocks.

These biosynthetic processes are critical to the life of the cell, take place constantly, and demand energy provided by ATP and other high-energy molecules like NADH (nicotinamide adenine dinucleotide) and NADPH.

Living organisms are not in equilibrium because the system at equilibrium cannot perform work. As living organisms work continuously, they cannot afford to reach equilibrium. 

The living organisms exist in a steady-state characterized by the concentration of each of the biomolecules. These biomolecules are in metabolic flux.

• Polysaccharides are formed by glycosidic linkages of monosaccharides.
• Proteins are formed by peptide linkages of amino acids.
• Nucleic acids are formed through Phospho-diester linkage between nucleotides.

All chemical reactions, including exothermic reactions, need activation energy to get started.
Activation energy is needed so reactants can move together, overcome forces of repulsion, and start breaking bonds.

The rate of oxygen consumption is commonly used to infer metabolic energy use in heterotrophic organisms because these organisms use oxygen in respiration to release energy via the Krebs cycle. 

Allosteric control refers to a type of enzyme regulation involving the binding of a non-substrate molecule, known as the allosteric effector, at locations on the enzyme other than the active site.

All the biomolecules are constantly being changed into some other biomolecules and also made from some other biomolecules. The turnover of biomolecules takes place continuously. All these reactions are together called metabolism.

Calories are needed to provide energy so, the body functions properly. The number of calories in a food depends on the amount of energy the food provides.

The number of calories a person needs depends on age, height, weight, gender and activity level. People who consume more calories than they bum off in normal daily activity or during exercise are more likely to be overweight.
Fat (1 gram) = 9 calories
Protein (1 gram) = 4 calories
Carbohydrates (1 gram) = 4 calories
Tri-glycerol is an ester derived from glycerol and three fatty acids. It is the main constituent of vegetable oil and animal fats.

Therefore, the approximate ratio of the energy content in kcal/g of carbohydrate: protein : tri-glycerol is 1 : 1 : 2.

Catabolic pathways involve the degradation of complex molecules into simpler ones, releasing the chemical energy stored in the bonds of those molecules. Conversion of glucose to lactic acid glucose molecule is catabolic pathway.