Units 12 & 13 Exam

What are pyrimidines in DNA?

• Types of nucleotides

• Types of base pairs

• Types of sugars

• Types of bases

What principle is necessary to preserve the sequence of DNA during replication?

• Base pairing is complementary.

• One gene codes for one polypeptide.

• Substrates are specific to enzymes.

• The genetic code is universal.

The diagram shows part of a DNA molecule that is being replicated.

Where would DNA polymerase link the next nucleotide during replication?

• I

• II

• III

• IV

The diagram represents part of the DNA molecule.

What are the parts labelled I, II and III?

• hydrogen bond, base, deoxyribose

• hydrogen bond, deoxyribose, phosphate group

• covalent bond, base, deoxyribose

• covalent, deoxyribose, phosphate group

The percentage of thymine in the DNA of an organism is approximately 30%. What is the percentage of guanine?

• 70%

• 30%

• 40%

• 20%

Which enzyme catalyzes the elongation of the leading strand?

• RNA polymerase

• Helicase

• DNA polymerase

• Ligase

Which base is connected to its complementary base in a base pair by three hydrogen bonds?

• Uracil

• Thymine

• Guanine

• Adenine

A small amount of a suspect’s DNA is obtained from a crime scene. What techniques would be used to carry out DNA profiling?

• Gel electrophoresis and paternity testing

• Paternity testing and the polymerase chain reaction (PCR)

• Polymerase chain reaction (PCR) and gel electrophoresis

• Test crossing and pedigree analysis

What type of enzyme could be used to cut a DNA molecule as indicated by the dotted line on the diagram below?

• DNA ligase

• DNA polymerase

• Helicase

• Restriction enzyme

How can fragments of DNA be separated?

• Using polymerase chain reaction (PCR)

• Using gel electrophoresis

• Using gene transfer

• Using gene cloning