If the base pairs in a dna strand were held together with covalent bonds instead of hydrogen bonds, how would cells have to operate differently? a) new dna would need to be made each time the strand was opened. b) the cell would have to take in and use more energy in order to break the covalent bonds. c) each time the dna strand opened the cell would need to replace the nitrogenous bases. d) the cell could only open and close the dna strand when it replicated.

 the option b is correct because covalent bond is stronger than hydrogen bond ...The cell would have to take in and use more energy in order to break the covalent bonds.

Carbon-14 has a half-life of 5,730 years and most igneous rock is older than that.

Proteins are the workhorses of the cell, controlling virtually every reaction within as well as providing structure and serving as signals to other cells. proteins are long chains of  amino acids  , and the exact sequence of the amino acids determines the final structure and function of the protein. instructions for that sequence are encoded in  genes  . to make a particular protein, a messenger ribonucleic acid (mrna) copy is made from the gene (in the process called  transcription  ), and the mrna is transported to the  ribosome  . protein synthesis, also called  translation  , begins when the two ribosomal subunits link onto the mrna. this step, called initiation, is followed by elongation, in which successive amino acids are added to the growing chain, brought in by transfer rnas (trnas). in this step, the ribosome reads the  nucleotides  of mrna three by three, in units called  codons  , and matches each to three nucleotides on the trna, called the anticodon. finally, during termination, the ribosome unbinds from the mrna, and the  amino acid  chain goes on to be processed and folded to make the final, functional protein