DNA Identification and Structure Flashcards
What aspects of DNA structure contribute to its stability?
The stability of DNA is contributed by:
* Hydrogen bonding between complementary bases
* Base stacking
Why is RNA less stable than DNA?
RNA is less stable due to the presence of a reactive 2’ OH group compared to the 2’ H in DNA.
What is the directionality of the two strands of DNA?
The two strands of DNA are antiparallel
What is Chargaff’s rule?
Chargaff’s rule states that the percent of adenine equals the percent of thymine and the percent of cytosine equals the percent of guanine. (A=T and C=G)
What is the significance of the 10.0 nucleotides in a complete turn of the DNA double helix?
There are approximately 10.0 nucleotides in each strand per complete 360° turn of the helix.
What is the primary structure/difference of an RNA strand from a DNA strand?
The primary structure of an RNA strand is similar to DNA but uses Uracil instead of Thymine and Ribose instead of Deoxyribose.
Fill in the blank: The most abundant proteins in chromatin are _______
histones
What are the two types of chromatin?
- Euchromatin - condenses and decondenses during cell cycle
- Heterochromatin - remains condensed over the cell cycle
True or False: Bacterial DNA is typically associated with histone proteins.
False
How does DNA packaging solve the problem of fitting DNA into a cell?
DNA packaging allows for tight compaction of DNA while permitting local access for replication and transcription.
What is the role of the 2’ OH group in RNA?
The 2’ OH group in RNA makes it more reactive and less stable than DNA.
What are the components of a nucleotide?
- A phosphate group
- A pentose sugar
- A nitrogenous base
What did Rosalind Franklin use to study the structure of DNA?
Rosalind Franklin used X-ray diffraction to study wet fibers of DNA.
What is the function of the sugar-phosphate backbone in DNA?
The sugar-phosphate backbone provides structural support and stability to the DNA molecule.
Fill in the blank: The RNA genome of HIV is integrated into host DNA through _______.
reverse transcription
What did the Hershey-Chase experiment demonstrate?
The Hershey-Chase experiment confirmed that DNA is the genetic material.
What are the four criteria that genetic material must fulfill?
- Information
- Transmission
- Replication
- Variation
What is the significance of the 9.5 Å in the discovery of the double helix?
The 9.5 Å refers to the distance between each complete turn of the DNA helix.
What is the difference between purines and pyrimidines?
- Purines: Adenine and Guanine
- Pyrimidines: Cytosine, Thymine (in DNA), and Uracil (in RNA)
What does DNA sequencing refer to?
DNA sequencing refers to determining the identity and order of nucleotides in a DNA molecule.
True or False: Whole-genome sequencing identifies all nucleotides within a given genome.
True
What is the consequence of bases pairing with identical bases in DNA?
If bases paired with identical bases, it would hinder DNA’s capacity to serve as a source of genetic information.
What is the main finding of Griffith’s experiment?
Griffith’s experiment identified DNA as the source of genetic information through the transformation of bacteria.
What are the three main structures of DNA?
- nucleotide sequence
- double stranded helix
- higher-order coiling (super coiling)
