OCR (A) Biology A-level: Nucleotides and Nucleic Acids

Semi-conservative replication of DNA ensures that each new DNA molecule contains one original strand and one newly synthesized strand. This allows for the genetic information to be passed on from one generation of cells to the next.

Exons are the coding regions of the genome that are translated into proteins, while introns are the non-coding regions that are not translated into proteins.

The genetic code is non-overlapping, meaning each triplet is read only once, and it is also degenerate, meaning multiple codons can code for the same amino acid. These features reduce the phenotypic effects of mutations and make the genetic code more adaptable.

<p>The genetic code consists of triplets of bases, known as codons, where each codon codes for a specific amino acid. This allows the sequence of amino acids in a polypeptide chain to be determined by the sequence of bases in the DNA.</p> Signup and view all the answers

<p>Protein synthesis consists of two main stages: transcription and translation. Transcription occurs in the nucleus and involves the synthesis of mRNA from a DNA template, while translation occurs in the cytoplasm and involves the synthesis of a polypeptide chain using the mRNA as a template.</p> Signup and view all the answers

<p>Mutations in the DNA sequence can alter the amino acid sequence of the resulting protein, which can lead to changes in the protein's structure and function. This can have various effects, including causing harmful conditions like cystic fibrosis or sickle cell anemia.</p> Signup and view all the answers

<p>Deoxyribose, a phosphate group, and one of the organic bases adenine, cytosine, guanine, or thymine</p> Signup and view all the answers

<p>A double helix composed of two polynucleotides joined together by hydrogen bonds between complementary bases</p> Signup and view all the answers

<p>ATP serves as a source of energy in the cell.</p> Signup and view all the answers

<p>ATP hydrolase</p> Signup and view all the answers

<p>Energy is released when ATP is hydrolyzed to form ADP and a phosphate molecule.</p> Signup and view all the answers

<p>Condensation of ADP and inorganic phosphate catalyzed by ATP synthase</p> Signup and view all the answers