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38 Cards in this Set
- Front
- Back
what are the four nitrogen bases |
1. cytosine 2. guanine 3. adenine 4. thymine |
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what nitrogen bases are purines |
adenine and guanine |
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what is a purine |
double ringed |
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what bases are pyrimidines |
thymine and cytosine |
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what is a pyrimidine |
single ringed |
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what makes up DNA |
nucleotides |
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what makes up a nucleotide |
1. five carbon sugar 2. phosphate group 3. nitrogenous base |
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what are the two base pairs |
1. adenine and thymine (by two hydrogen bonds) 2. cytosine and guanine (by three hydrogen bonds) |
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what is the difference between the 5' end and the 3' end |
5' end: phosphate group 3' end: hydroxyl group (OH) |
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helicase |
unwinds double helix in to 2 separate stands of DNA |
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polymerase |
adds nucleotides to existing single strand |
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ligase |
brings together Okazaki fragments |
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topoisomerase |
cuts and rejoins the helix |
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RNA primase |
catalyzes the synthesis of RNA primers |
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what are the differences between DNA and RNA |
1. RNA is single stranded and DNA is double stranded 2. RNA has ribose sugar and DNA has deoxyribose sugar 3. RNA has the base uracil instead of thymine in DNA |
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what are the three types of RNA |
1. mRNA 2. rRNA 3. tRNA |
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what is mRNA |
copies and carries stored DNA info to ribosome |
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what is rRNA |
synthesizes protein |
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what is tRNA |
reads mRNA message, shuttles amino acids to ribosome |
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what are the three stages in transcription |
1. initiation 2. elongation 3. termination |
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at what site does transcription begin |
promoter |
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only one DNA strand is copied, and this is called the |
sense strand or the template strand |
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the other uncopied strand is known as the |
nonsense strand |
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RNA molecules replace DNA thymine with what |
uracil |
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exons |
coding regions of mRNA that expresses the code for the polypeptide |
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introns |
noncoding regions of mRNA |
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codon |
a group of three bases (letters) that code for one (of 20) amino acids |
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RNA processing includes 3 ideas |
1. poly A tail on the 3' end 2. 5' end GTP cap 3. spliceosomes to rid the mRNA of introns |
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point mutation |
one base is substituted for another |
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nonsnese mutation (point mutation) |
early termination of protein synthesis |
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missense mutation (point) |
codon altered producing a different amino acid |
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silent mutation (point) |
creates a new codon that results in the same amino acid |
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insertion (frameshift) |
gain of gene |
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deletion (frameshift) |
loss of a gene |
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duplication |
extra copy of genes caused by unequal crossing over |
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inversion |
when letters are reversed |
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translocation |
when a portion of two different chromosomes breaks and rejoins in a way that the DNA sequence is lost, repeated, or interrupted |
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recombinant DNA |
generated by combining DNA from multiple sources to create a unique DNA that is not found in nature |