Tag: carbohydrate metabolism

Glycolysis is an oxidative process in which one molecule of glucose is partially oxidised into two molecules of pyruvate in a series of enzyme catalysed reactions. Glycolysis, the major pathway for glucose metabolism, occurs in the cytosol of cells. It is a unique pathway that occurs aerobically as well as anaerobically and does not involve molecular oxygen.

All the processes occur in the absence of oxygen i.e., anaerobic condition. 

The pentose sugars ribose and deoxyribose are part of the nucleotides that make up the crucial nucleic acids like DNA and RNA. So the correct option is 'Erythrose'.

FSH is a proteinaceous hormone. It does not enter its target cells, thus, it never reaches to cytoplasm. Instead, it binds to the receptor present on the cell membrane and activates a membrane bound enzyme that causes conversion of ATP to cAMP. This then alters the activities of enzyme in the cytoplasm.

In electron transport chain, there are 7 electron acceptors, which are as follows $Co-Q\rightarrow Cyt\,\, b\rightarrow Cyt \,\,{c} _{1} \rightarrow Cyt \,\,c\rightarrow Cyt \,\,a\rightarrow Cyt \,\,{a} _{3}\rightarrow{O} _{2}$. Oxygen is the ultimate electron acceptor. These electron acceptors are present in a specific sequence along inner mitochondrial membrane.

• The thyroid gland is composed of two lobes that are located on either side of the trachea.
• Follicular cells of the thyroid gland synthesize two hormones, tetraiodothyronine or thyroxine ($T _4$) and triiodothyronine ($T _3$). 
• Thyroid hormones play an important role in the regulation of the basal metabolic rate. 
• Hence the hormone secreted by the thyroid gland is thyroxine.
• So, the correct answer is 'Thyroxine'.

Any chemical reaction includes the formation of transition state between reactant and product. Formation of transition state requires high energy content of reactant molecules for alignment of reacting groups, the formation of transient unstable charges, rearrangements of chemical bonds etc. The energy required for formation of the transition state is termed as activation energy. Enzymes enhance the rate of reaction by lowering down the activation energy of transition state. Thus, the correct answer is option C.

• Enzymes provide activation energy for the reactions they catalyze.
• Catalysts lower the activation energy for reactions. 
• The lower the activation energy for a reaction, the faster the rate. Thus enzymes speed up reactions by lowering activation energy.so, option A is correct.

Any chemical reaction includes the formation of transition state between reactant and product. The energy required for formation of the transition state is termed as activation energy. Enzymes enhance the rate of reaction by lowering down the activation energy of transition state. Thus, the correct answer is option C.

The transition state is the state of the activated complex which is highly unstable and readily changes into the product.  At the transition state, the enzyme attaches to the substrate to form an enzyme-substrate complex by forming a weak chemical bond. Binding energy is the free energy that is released by the formation of weak interactions between a complementary substrate and enzyme.