DNA Structure and Gene Expression
Purines ** Answ** Double ring structure --> adenine and guanine
Pyrimidines ** Answ** Single ring structure --> thymine and cytosine (and uracil)
How many hydrogen bonds are between A and T? ** Answ** 2
How many hydrogen bonds are between G and C? ** Answ** 3
Can purine be with another purine? ** Answ** No, it is always a purine with a
pyrimidine
Strands of DNA are always... ** Answ** antiparallel
Since they are antiparallel, that means... ** Answ** 5' is uppermost in left strand, 3'
is uppermost in right strand
DNA replication ** Answ** process of copying double helix DNA
What enzyme carries out DNA replication? ** Answ** DNA polymerase
Why is the process termed semiconservative? ** Answ** New double helix has 1
conserved strand and 1 new strand
Which enzyme unzips DNA ** Answ** DNA helicase
Complementary bases positioned and joined by which enzyme? ** Answ** DNA
polymerase
Leading Strand ** Answ** Follows DNA helicase in 5' to 3' direction
Lagging Strand ** Answ** Forms Okazaki fragments in 3' to 5' direction
Okazaki Fragments ** Answ** Short DNA fragments that form on lagging strand
Which enzyme connects Okazaki fragments and seals any breaks in the sugar-
phosphate? ** Answ** DNA ligase
Gene Expression ** Answ** Process that uses gene sequence to make protein
Types of RNA (need to know) ** Answ** mRNA, tRNA, rRNA
Where does transcription occur? ** Answ** Nucleus
Purines ** Answ** Double ring structure --> adenine and guanine
Pyrimidines ** Answ** Single ring structure --> thymine and cytosine (and uracil)
How many hydrogen bonds are between A and T? ** Answ** 2
How many hydrogen bonds are between G and C? ** Answ** 3
Can purine be with another purine? ** Answ** No, it is always a purine with a
pyrimidine
Strands of DNA are always... ** Answ** antiparallel
Since they are antiparallel, that means... ** Answ** 5' is uppermost in left strand, 3'
is uppermost in right strand
DNA replication ** Answ** process of copying double helix DNA
What enzyme carries out DNA replication? ** Answ** DNA polymerase
Why is the process termed semiconservative? ** Answ** New double helix has 1
conserved strand and 1 new strand
Which enzyme unzips DNA ** Answ** DNA helicase
Complementary bases positioned and joined by which enzyme? ** Answ** DNA
polymerase
Leading Strand ** Answ** Follows DNA helicase in 5' to 3' direction
Lagging Strand ** Answ** Forms Okazaki fragments in 3' to 5' direction
Okazaki Fragments ** Answ** Short DNA fragments that form on lagging strand
Which enzyme connects Okazaki fragments and seals any breaks in the sugar-
phosphate? ** Answ** DNA ligase
Gene Expression ** Answ** Process that uses gene sequence to make protein
Types of RNA (need to know) ** Answ** mRNA, tRNA, rRNA
Where does transcription occur? ** Answ** Nucleus
