Molecular marker

The size marker is used during electrophoresis to:

• accelerate the separation of DNA fragments

• determine the size of separated DNA fragments

• change the length of separated DNA fragments

The specificity of the fragment amplified in PCR is determined by

• primers sequences

• polymerase type

• presence of magnesium ions

The optimal elongation temperature for most DNA polymerase is

• 72°C

• 55°C

• 95°C

What is the purpose of PCR?

• To produce millions of copies of a specific region of DNA

• To add nucleotides to a DNA sequence

• To attach the primers

Why does PCR require a specific type of polymerase?

• Taq polymerase can withstand the range of temperatures in PCR without denaturing.

• Taq polymerase is the most inexpensive type of polymerase.

• Taq polymerase is the most common type of polymerase.

What happens during the Annealing step of PCR?

• The primers attach to the targeted DNA region.

• Primers are created.

• Double helix is created.

What happens during denaturation step

• DNA double helix structure is separated

• Taq polymerase add nucleotides

• Primers are extended

What type of bonds holds the two strands of DNA together?

• Ionic bonds

• Hydrogen bonds

• Chemical bond

If the primer sequence is TCG, what section of DNA will it anneal?

• GCA

• AGC

• GCA

Why do the fragments of DNA in gel electrophoresis travel away from the negative electrode?

• DNA is positively charged so attracted to the negative end of the unit

• The agarose gel in negatively charged

• DNA is negatively charged so attracted to the positive end of the unit