Growth hormone affects growth by controlling the production of... at cellular level :-

Options

A. r-RNA
B. m-RNA
C. t-RNA
D. None of these

Answer

**Step-by-Step Solution:**

1. **Understanding Growth Hormone (GH):** Growth hormone is a peptide hormone that plays a crucial role in growth, metabolism, and body composition. It stimulates growth and cell reproduction.

2. **Identifying the Cellular Level:** The question specifies that we are looking at the effects of growth hormone at the cellular level. This typically involves the processes of gene expression and protein synthesis.

3. **Role of mRNA:** At the cellular level, growth hormone primarily affects the production of messenger RNA (mRNA). mRNA is crucial because it carries the genetic information from DNA to the ribosomes, where proteins are synthesized.

4. **Growth Phases:** The transcript mentions different growth phases (log phase, stationary phase) and how mRNA levels vary in these phases. In the log phase, when cells are actively dividing and growing, mRNA levels are high, especially when glucose is the primary energy source.

5. **Influence of Substrates:** The transcript discusses how the presence of glucose induces higher levels of mRNA compared to other substrates like ethanol. This indicates that growth hormone influences mRNA production based on the metabolic conditions of the cell.

6. **Conclusion:** Based on the information provided, growth hormone affects growth by controlling the production of mRNA at the cellular level.

7. **Final Answer:** The answer to the question is **mRNA**.

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