Bio 101

Select the statements that best describe how nucleotides pair with one another in a DNA molecule. Select the TWO answers that are correct.

-Adenine pairs with thymine, and guanine pairs with cytosine. -Nucleotides pair with each other, joining two strands of DNA by hydrogen bonding.

Why does DNA travel toward the positive electrode during gel electrophoresis?

DNA is negatively charged, and opposite charges attract.

Why is DNA replication called "semiconservative"?

DNA is replicated, each copy having one strand of the original molecule and one newly synthesized strand.

Why can the same short tandem repeat region vary in length between the two copies of a chromosome of an individual?

Each chromosome is inherited from a different parent.

Select the statement that best describes the function of heating and cooling in PCR.

Heating facilitates strand denaturation, and cooling facilitates primer attachment.

What is the polymerase chain reaction (PCR)?

PCR produces many copies of a DNA sequence from a small sample using temperature cycling, primers, free nucleotides, and polymerase enzymes.

Select the best description of a short tandem repeat.

a nucleotide sequence of at least two bases that is continuously repeated in a DNA strand

What factor does gel electrophoresis use to separate DNA molecules?

length of individual DNA molecules

. Select the parts that make up the backbone of the DNA molecule. Select the TWO answers that are correct.

phosphate sugar

Select the statements that correctly describe how a new DNA molecule reflects the original DNA molecule from which it was copied. Select the TWO answers that are correct.

-Each new DNA molecule contains an original strand and a newly synthesized strand. -Base pairing rules duplicate the base pairs of the original molecule in the new molecule.