HW 9

What kind of bonding between complementary nitrogen bases hold the two strands of the DNA molecule together?

hydrogen

What are the three steps in DNA replication? i. Ribosomes are attached to the DNA molecule at the start sequence. ii. The enzyme, helicase, unwinds the DNA molecule. iii. Free nucleotides match with complementary bases in the DNA strands. iv. Amino acids are used to hold nucleotides in place. v. The phosphate of the new nucleotide is attached to the deoxyribose sugar of the adjacent nucleotide on the same strand

ii iii v

Where in the eukaryotic cell does DNA replication occur?

in the nucleus

The product of DNA replication is

two identical molecules of DNA

In both prokaryotes and eukaryotes, the replication is semi-conservative.

True

A random change in the sequence of the DNA that becomes permanent is called

a mutation

The two purines bases in DNA are:

adenine;guanine

The two strands of DNA run into the opposite directions, this is called .....

antiparallel

What components make up the backbone (the outside of the strands) of the DNA molecule?

deoxyribose and phosphate groups

What are the three molecular components of a nucleotide?

deoxyribose, nitrogen bases and phosphate groups

If the sequence of bases in one strand of DNA is 5' TAGCCT3', the sequence of bases in the complimentary strand will be

5'AGGCTA3'

What enzyme is responsible for adding new nucleotides to a growing DNA chain during replication?

DNA Polyamerase

What is the difference between a purine and a pyrimidine?

Purines are nitrogen bases composed of two rings; pyrimidines are nitrogen bases composed of one ring

In DNA base pairing, A pairs with ______ and G pairs with ______.

T;C