14(i) 1 Q5(d)(i)-GCE-Biology - June 2014-F212/01 code for (one or more) polypeptide(s) ; ACCEPT protein amino acid sequence IGNORE 14(ii) 5 1 double stranded ; Q5(d)(ii)-GCE-Biology -June 2014-F212/01 AWARD marks from clearly annotated diagram 2 each / both (strands) act as template ; 1 ACCEPT double helix or two , polynucleotides / strands / chains antiparallel strands or hydrogen bonds , easily , break / form , 3 between 1 IGNORE one old and one new strand bases ; 2 IGNORE either 4 complementary (specified) base , pairing / AW NOTE are 2 strands which act as = 2 ; ‘there templates’ marks (mp 1 and 2) Foundations in Biology; L,M,H 5 purine (only able to) bind to pyrimidine ; Nucleotides and nucleic acids 3 ACCEPT weak H bonds between bases break 6 (due to) different sizes of purines and pyrimidines ; 3 IGNORE refs to H bonds , breaking / forming , without qualification that the bonds are weak or , form / break , 7 hydrogen bonding different between A & T and easily C & G 4 IGNORE complementary nucleotides unless qualified or with examples of base-pairing 3 H bonds between C & G and names of bases with phonetic spellings 7 ACCEPT 2 H bonds between A & T ; 7 DO NOT CREDIT thyamine 7ACCEPT A=T and without reference to hydrogen C≡G bonds
14(i) 1 code for (one or more) polypeptide(s) ; Q5(d)(i)-GCE-Biology - June 2014-F212/01 ACCEPT protein IGNORE amino acid sequence Foundations in Biology; Nucleotides and nucleic acids L,M,H 14(ii) 5 1 double stranded ; 2 each / both (strands) act as template ; 3 hydrogen bonds , easily , break / form , between bases ; 4 complementary (specified) base , pairing / AW ; 5 purine (only able to) bind to pyrimidine ; 6 (due to) different sizes of purines and pyrimidines ; 7 hydrogen bonding different between A & T and C & G or 3 H bonds between C & G and 2 H bonds between A & T ; Q5(d)(ii)-GCE-Biology -June 2014-F212/01 AWARD marks from clearly annotated diagram 1 ACCEPT double helix or two , polynucleotides / strands / chains or antiparallel strands 1 IGNORE one old and one new strand 2 IGNORE either NOTE ‘there are 2 strands which act as templates’ = 2 marks (mp 1 and 2) 3 ACCEPT weak H bonds between bases break 3 IGNORE refs to H bonds , breaking / forming , without qualification that the bonds are weak or , form / break , easily 4 IGNORE complementary nucleotides unless qualified with examples of base-pairing 7 ACCEPT names of bases with phonetic spellings 7 DO NOT CREDIT thyamine 7ACCEPT A=T and C≡G without reference to hydrogen bonds
gce_a_as_level_biology_a_topic__-_foundations_in_biology_-_answers.docx