Module 1: DNA Flashcards
Linking of monomers to form polymers is done by a process known as _________.
Condensation/dehydration
The process of polymers being broken down into monomers is known as _________.
Hydrolysis
Be able to distinguish between purines and pyrimidines:
Purines: 2 rings (adenine, guanine)
Pyrimidines: 1 ring (Cytosine, Thymine, Uracil)
Which of the following purines contain a double bonded oxygen (carbonyl) on the top of the ring?
A. Adenine B. Guanine C. Cytosine D. Thymine E. Uracil
B. Guanine
Guanine = carbonyl
Adenine = NH2
What is the difference between a nucleotide and a nucleoside?
Nucleotide = sugar, base, phosphate
Nucleoside = sugar, base
What carbon does the base (purine/pyrimidine) attach to on the sugar?
Carbon 1 = base
Identify what attaches to the different carbons of a sugar:
Carbon 1 = base
Carbon 2 = ribose/deoxyribose
Carbon 3 = phosphodiester bond (phosphate)
Carbon 5 = phosphodiester bond (phosphate)
Which of the following pyrimidines contain a methyl group (CH3) bonded to the ring?
A. Adenine B. Guanine C. Cytosine D. Thymine E. Uracil
D. Thymine
Pyrimidines:
Cytosine = NH2 and carbonyl on the ring
Thymine = CH3 and 2 carbonyls
Uracil = 2 carbonyls (same as thymine w/o CH3)
Purines:
Adenine = NH2
Guanine = Carbonyl
What is the difference between ribose and deoxyribose?
Ribose = 2 OH’s
Deoxyribose = No OH on carbon #2
Where are phosphodiester bonds found in DNA?
Phosphodiester bonds link sugars
H-bonds link bases together (G-C has 3 H-bonds)
What 3 ways can you separate (denature) DNA strands?
- change pH
- increase heat
- DNA replication
Which of the following studies proved that genes were made of DNA and NOT protein?
A. Hershey and Chase experiment
B. Meselson and Stahl experiment
A. Hershey and Chase experiment
_______ revealed that DNA synthesis is semiconservative.
A. Hershey and Chase experiment
B. Meselson and Stahl experiment
B. Meselson and Stahl experiment
Hershey and Chase: genes are made of DNA
Meselson and Stahl: semiconservative
Which of the following is FALSE regarding DNA synthesis?
A. Occurs at the replication fork and is bidirectional B. Semiconservative C. Proceeds in the 3' to 5' direction D. Requires an RNA primer E. All of the above are true
C. Proceeds in the 3’ to 5’ direction
DNA synthesis proceeds in the 5’ to 3’ direction
Which of the following enzymes in DNA replication is a replication initiation factor that promotes denaturation of DNA at the origin of replication?
A. DnaA B. Helicase C. Single stranded DNA binding protein D. Topoisomerase E. Primase F. DNA polymerase G. Telomerase
A. DnaA
DNA replication steps:
- DnaA initiates partial denaturation of DNA (begins the unwinding of DNA)
- Helicase travels along DNA in the 5’ to 3’ direction and separates the DNA strands
- Single stranded binding proteins bind to the unzipped portion of DNA to prevent DNA from re-forming a double helix (keeps both strands of DNA from re-binding)
- Topoisomerase relieves the stress caused by unzipping DNA
- Primase synthesis RNA primers to prime DNA synthesis
- DNA polymerase replicate DNA