IB DP Biology Mock Exam HL Paper 1B Set 2- 2025 Syllabus
IB DP Biology Mock Exam HL Paper 1B Set 2
Prepare for the IB DP Biology Exam with our comprehensive IB DP Biology Exam Mock Exam HL Paper 1B Set 2. Test your knowledge and understanding of key concepts with challenging questions covering all essential topics. Identify areas for improvement and boost your confidence for the real exam
Question
(a) Label the parts of the DNA diagram indicated by I, II, III and IV.
b.(i) State one role of nucleosomes in eukaryotic cells.
(ii) Outline how Hershey and Chase’s experiment provided evidence for DNA as the genetic material.
(iii) State one function for a region of DNA that does not code for proteins.
c.Outline the role of the following in translation.
(i) A-site of ribosomes
(ii) tRNA activating enzymes
Answer/Explanation
Ans:
a)
a. I. cytosine (NOT simply Nitrogenous base)
b. II. sugar phosphate/covalent/phosphodiester bond
c. III. phosphate (NOT phosphorus)
d. IV.deoxyribose (NOT pentose sugar)
b (i)
a. help to supercoil/pack DNA in chromosomes
b. help to regulate transcription / gene expression
b (ii)
a. experiment is meant to determine whether DNA or protein is the genetic material
b. viruses/bacteriophages grown in radioactive S/S35 which enters the protein coat
c. viruses/bacteriophages grown in radioactive P/P32 which enters the DNA
d. «radioactive» viral DNA entered the bacterial cell during infection
OR
«radioactive» viral protein did not enter the bacterial cell during infection
b (iii) regulator of gene expression/introns/telomeres/genes for tRNA / rRNA / promoter / enhancer / silencer / site for primer to bind / codes for mRNA primer
c (i) binding/entry of tRNA carrying amino acids/aminoacyl tRNA / charged tRNA / site of transfer of growing polypeptide chains/peptide bond formation
c (ii)
a. ATP «hydrolysis» provides energy for amino acid attachment
b. they attach a specific amino acid to the (3′ ) end / free CCA of a tRNA