Describe the structure of DNA (deoxyribonucleic acid).
DNA is a polynucleotie, usually double stranded, made up of nucleotides containing a nitrogenous base, (A,T,C or G) the sugar deoxyribose & a phosphate group.
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Describe the structure of RNA (ribonucleic acid)
RNA is a polynucleotide, usually single stranded, made up of nucleotides containing a nitrogenous base, (A,U,C or G), the sugar ribose & a phosphate group. There are three types of RNA.
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Describe how hydrogen bonding between complementary base pairs (A & T, C & G) on two antiparallel DNA polynucleotides leads to the formation of a DNA molecule.
2 types of nucleotide base- pyramidines & purines. Always pair up together. There are 2 H bonds between A & T and 3 between C & G. Strands are antiparallel because they run in opposite directions - sugars pointing in different directions.
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Describe how the twisting of DNA produces its 'double-helix' shape.
The antiparallel chains twist like a rope ladder to form the final structure - a double helix.
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Outline how DNA replicates semi-conservatively, with reference to the role of DNA polymerase.
DNA untwisted & unzipped by helicase causing H bonds between bases to break. Both strands now = template. Free DNA nucleotides complem. base pair (purine to pyrimidine) H bonds reform. SP backbone joined by DNA polymerase forming phosphodiester bonds
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What is a gene?
A sequence of DNA nucleotides that codes for a polypeptide.
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Outline the roles of DNA & RNA in living organisms.
wanted gene exposed by splitting H bonds. RNA nucleotides form complem strand. mRNA peels from DNA & leaves (nucleus). mRNA attaches to ribosome. tRNA brings a.a to ribosome in correct order. a.a joined by peptide bonds give protein with tertiary str
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What happens if there's a mutation & the sequence of nucleotides is changed during the roles of RNA & DNA in living organisms.
If theres a mutation, the sequence of amino acids will be changed. Leads to a change in the 3-D specific tertiary structure of the protein. & if its an enzyme, substrate will no longer fit active site.
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Other cards in this set
Card 2
Front
Describe the structure of RNA (ribonucleic acid)
Back
RNA is a polynucleotide, usually single stranded, made up of nucleotides containing a nitrogenous base, (A,U,C or G), the sugar ribose & a phosphate group. There are three types of RNA.
Card 3
Front
Describe how hydrogen bonding between complementary base pairs (A & T, C & G) on two antiparallel DNA polynucleotides leads to the formation of a DNA molecule.
Back
Card 4
Front
Describe how the twisting of DNA produces its 'double-helix' shape.
Back
Card 5
Front
Outline how DNA replicates semi-conservatively, with reference to the role of DNA polymerase.
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