DNA as the Genetic Code- Nature of DNA Flashcards
what does DNA stand for?
-Deoxyribonucleic acid
what is the role of DNA?
-allows the characteristics of a species to be passed through generations
-determines polypeptides
-makes the enzymes that controls cell metabolism
what is the structure of DNA?
-repeating units of deoxyribose sugar and phosphate
-double stranded linked together by the nitrogenous bases adenine, guanine, cytosine, thymine
how are the bases linked together?
-via hydrogen bonds
what is it that forms the specific DNA code?
-the linear order of the bases on one of the strands (template strand)
how many different types of amino acids are there?
-20
what is the basis which controls the overall polypeptide created?
-the sequence of amino acids in the primary structure
what is the definition of genetic code?
-the way in which the DNA codes for specific amino acids in specific positions in a polypeptide
what is the definition of a gene?
-the length of DNA coding for a particular polypeptide
how many bases does it take to code for an amino acid? what is this called?
-3
-base triplet
what are the 4 features of the genetic code?
-code is non-overlapping meaning each base is read only once
-code is degenerate means most amino acids will have more than one possible code
-some base triplets do not code for an amino acid but instead stop the coding sequence (stop codon) or start the sequence (start codon)
-it is universal meaning that it is the same in all living organisms
where and in what is the genetic code stored?
-in chromosomes in the nucleus
where does protein synthesis take place?
-in the cytoplasm
how does the genetic code pass from the nucleus to the cytoplasm?
-messenger RNA
what are the two processes of protein synthesis?
-transcription and translation
