American bullfrogs inhabit various habitats<span>, such as lakes, ponds, marshes, slow flowing rivers and streams.</span>
Ans.
There are twenty amino acids that take part in protein synthesis. These amino acids act as precursor for all protein molecules and are known as essential amino acids. Plants can synthesize all twenty amino acids from simple precursors, while animals can make only twelve amino acids. Animals obtain remaining eight amino acids by eating plants.
Thus, the correct answer is 'option) D.'
Ans.
Gene regulation or regulation of gene expression involves mechanisms, used by the cells to enhance or reduce the expression of specific genes to make proteins or RNA. Gene regulation occurs at transcriptional level and post-transcriptional level, which involves regulation at translational level or protein level.
Regulation at translational level or protein level is also important as regulation at transcriptional level. Translational regulation controls formation of proteins from mRNA molecules and includes non-coding mRNAs and repressor proteins. It is important for cell growth, differentiation and cellular response to stress and provides an immediate adjustment of gene expression by directly regulating the protein concentration.
Regulation at protein level involves regulation of active protein. It includes regulation by various small molecules, post-translational modifications (such as phosphorylation), and proteolysis. Regulation only at transcriptional level is not sufficient to provide proper gene regulation and leads to various drawbacks, such as Fragile X Syndrome (due to defect in a protein).
Thus, 'gene regulation is important both at transcriptional level and at post-transcriptional level (during translation or protein level).'
Answer:
You tell her that this is incorrect.
Explanation:
The given information is incorrect as both small and large ribosomal subunits are required for protein synthesis. The eukaryotic ribosomes have E, P, and A sites. The A and P sites bind to the aminoacyl tRNA that carry the amino acid encoded by the codon of the mRNA.
The formation of peptide bond occurs between the amino group of amino acid in A site and the carboxyl group of amino acid present on P site. Both 40S and 60S subunit of ribosome contribute the A and P sites.
