BIOLOGY 189 TEST PAPER 2025/2026 QUESTIONS AND
SOLUTIONS GRADED A+ TIP
✔✔What are mutations? - ✔✔permanent changes in the DNA sequence of a
chromosome.
✔✔What are nucleotide dimers and which type(s) of mutagen(s) usually causes them? -
✔✔Dimers cause mutations because polymerases tend to copy kinked DNA incorrectly.
Dimers can also block the progress of a polymerase, so DNA replication stalls or
collapses.UV rays in sunlight cause them
✔✔What is the Semiconservative Model of DNA replication? - ✔✔Semiconservative
replication produces two copies that each contained one of the original strands and one
new strand.
✔✔What is a gene? - ✔✔Unit of information encoded in the sequence of nucleotide
basis
✔✔Unit of information encoded in the sequence of nucleotide basis - ✔✔DNA ligase 1
connects the Okazaki fragments
✔✔Is DNA usually double-stranded or single-stranded? - ✔✔double-stranded
✔✔During transcription, what is the template and what is the product? - ✔✔DNA. The
product is mRNA
✔✔During transcription from DNA to RNA, you have the following DNA template. - ✔✔3'
GTACGCTCA 5'
✔✔What will be the resulting RNA strand? - ✔✔5' CATGCGAGT 3'
✔✔mRNA - ✔✔messenger RNA; type of RNA that carries instructions from DNA in the
nucleus to the ribosome
✔✔tRNA (transfer RNA) - ✔✔The form of RNA that carries each amino acid to the
ribsome to form the polypeptide chain (protein)
✔✔rRNA (ribosomal RNA) - ✔✔directs the translation of mRNA into proteins
✔✔What is the role of RNA polymerase? - ✔✔-binds to DNA during transcription and
separates the DNA strands
-then uses one strand of DNA as a template from which to assemble nucleotides into a
complementary strand of RNA
, ✔✔Is RNA usually double stranded or single stranded? - ✔✔single stranded
✔✔During transcription, which RNA nucleotide pairs with DNA's adenine? - ✔✔Uracil
✔✔What is gene expression? - ✔✔the process by which DNA directs protein synthesis,
includes two stages: transcription and translation
✔✔Where does translation take place? Which organelle? - ✔✔cytoplasm in ribosomes
✔✔What is a codon? - ✔✔a sequence of three nucleotides that together form a unit of
genetic code in a DNA or RNA molecule.
✔✔What is an exon? - ✔✔An expressed sequence of DNA; codes for a protein
✔✔What is an intron? - ✔✔sequence of DNA that is not involved in coding for a protein
(noncoding)
✔✔deletion mutation - ✔✔a mutation in which one or more pairs of nucleotides are
removed from a gene
✔✔substitution mutation - ✔✔Mutation in which a single base is replaced, potentially
altering the gene product.
✔✔Insertion - ✔✔A mutation involving the addition of one or more nucleotide pairs to a
gene.
✔✔Are mutations in exons or introns more likely to result in an altered protein? -
✔✔Exons
✔✔Are mutations permanent or temporary changes in the DNA sequence? -
✔✔Permanent changes in the DNA
✔✔Hershey and Chase - ✔✔concluded that the genetic material of the bacteriophage
was DNA, not protein.
✔✔Rosalind Franklin - ✔✔Used X-ray diffraction to discover the double-helical structure
of DNA.
✔✔Watson and Crick - ✔✔Developed the double helix model of DNA.
✔✔Avery - ✔✔genes are composed of DNA , DNA (not proteins) can transform the
properties of cells
SOLUTIONS GRADED A+ TIP
✔✔What are mutations? - ✔✔permanent changes in the DNA sequence of a
chromosome.
✔✔What are nucleotide dimers and which type(s) of mutagen(s) usually causes them? -
✔✔Dimers cause mutations because polymerases tend to copy kinked DNA incorrectly.
Dimers can also block the progress of a polymerase, so DNA replication stalls or
collapses.UV rays in sunlight cause them
✔✔What is the Semiconservative Model of DNA replication? - ✔✔Semiconservative
replication produces two copies that each contained one of the original strands and one
new strand.
✔✔What is a gene? - ✔✔Unit of information encoded in the sequence of nucleotide
basis
✔✔Unit of information encoded in the sequence of nucleotide basis - ✔✔DNA ligase 1
connects the Okazaki fragments
✔✔Is DNA usually double-stranded or single-stranded? - ✔✔double-stranded
✔✔During transcription, what is the template and what is the product? - ✔✔DNA. The
product is mRNA
✔✔During transcription from DNA to RNA, you have the following DNA template. - ✔✔3'
GTACGCTCA 5'
✔✔What will be the resulting RNA strand? - ✔✔5' CATGCGAGT 3'
✔✔mRNA - ✔✔messenger RNA; type of RNA that carries instructions from DNA in the
nucleus to the ribosome
✔✔tRNA (transfer RNA) - ✔✔The form of RNA that carries each amino acid to the
ribsome to form the polypeptide chain (protein)
✔✔rRNA (ribosomal RNA) - ✔✔directs the translation of mRNA into proteins
✔✔What is the role of RNA polymerase? - ✔✔-binds to DNA during transcription and
separates the DNA strands
-then uses one strand of DNA as a template from which to assemble nucleotides into a
complementary strand of RNA
, ✔✔Is RNA usually double stranded or single stranded? - ✔✔single stranded
✔✔During transcription, which RNA nucleotide pairs with DNA's adenine? - ✔✔Uracil
✔✔What is gene expression? - ✔✔the process by which DNA directs protein synthesis,
includes two stages: transcription and translation
✔✔Where does translation take place? Which organelle? - ✔✔cytoplasm in ribosomes
✔✔What is a codon? - ✔✔a sequence of three nucleotides that together form a unit of
genetic code in a DNA or RNA molecule.
✔✔What is an exon? - ✔✔An expressed sequence of DNA; codes for a protein
✔✔What is an intron? - ✔✔sequence of DNA that is not involved in coding for a protein
(noncoding)
✔✔deletion mutation - ✔✔a mutation in which one or more pairs of nucleotides are
removed from a gene
✔✔substitution mutation - ✔✔Mutation in which a single base is replaced, potentially
altering the gene product.
✔✔Insertion - ✔✔A mutation involving the addition of one or more nucleotide pairs to a
gene.
✔✔Are mutations in exons or introns more likely to result in an altered protein? -
✔✔Exons
✔✔Are mutations permanent or temporary changes in the DNA sequence? -
✔✔Permanent changes in the DNA
✔✔Hershey and Chase - ✔✔concluded that the genetic material of the bacteriophage
was DNA, not protein.
✔✔Rosalind Franklin - ✔✔Used X-ray diffraction to discover the double-helical structure
of DNA.
✔✔Watson and Crick - ✔✔Developed the double helix model of DNA.
✔✔Avery - ✔✔genes are composed of DNA , DNA (not proteins) can transform the
properties of cells
