Term | Definition |
DNA | Deoxyribonucleic Acid |
Double Helix | shape of DNA |
Purines | Adenine and Guanine |
Pyrimidines | Cytosine and Thymine |
replication | process of copying DNA |
Helicases | enzymes that separate base pairs |
DNA Polymerase | enzymes that bind to the separated chains of DNA |
Complimentary Base Pairs | C-G, A-T |
1 in 1000000000 (1 billion) | amount of error in paired nucleotides after proofreading |
RNA | Ribonucleic Acid |
DNA nucleotide | sugar (deoxyribose), phosphate (phosphorus), and 1 nitrogen base (adenine, guanine, cytosine, thymine) |
RNA nucleotide | sugar(ribose), phosphate, nitrogen containing base |
messenger RNA (mRNA) | carries genetic info from DNA to cytoplasm; single uncoiled chain |
transfer RNA (tRNA) | binds to specific amino acids; 45 varieties; single chain of approx. 80 RNA nucleotides; hairpin shape |
ribosomal RNA (rRNA) | most abundant; globular form; makes up the ribosome where proteins are made |
transcription | process by which genetic info is copied from DNA to RNA |
mRNA, tRNA, rRNA | products of transcription (transcripts) |
protein synthesis | production of proteins; amount/type of protein determine structure & function of the cell |
proteins | polymers; made of 1+ polypeptides; may contain 1000s of amino acids |
amino acids | 20; determines how the polypeptides will twist and fold into the 3D protein structure |
genetic code | correlation between a nucleotide sequence and an amino acid sequence; used by most organisms to translate mRNA transcripts into proteins |
codon | 3 mRNA nucleotides; codes for specific amino acids; some do not code at all( signal for translation of an mRNA to start/stop |
AUG | start codon |
UAA,UAG, UGA | stop codon |
translation | process of assembling polypeptides from info encoded in mRNA; begins when mRNA leaves the nucleus through pores in the nuclear membrane |
anticodon | the loop opposite of the site of the amino acid attachment bears a sequence of 3 nucleotides; complementary; pairs with the mRNA codon |
ribosomes | composed of rRNA and proteins and are free in the cytoplasm and attached to the endoplasmic reticulum |
binding sites | one holds and mRNA transcript so that its codons are accessible to rRNA molecules; the other two hold tRNAs whose anticodons pair with mRNA codons |
DNA vs. RNA | in RNA sugar is ribose, thymine is NOT present, but uracil is, and it is single stranded |
adenine and guanine | made of two rings of carbon; purines |
cytosine and thymine | made of one ring of carbon; pyrimidines |