U1 KA1 -DNA Structure Flashcards
What is the structure of DNA?
DNA is a double-helix consisting of repeating units of DNA nucleotides.
DNA nucleotides are the building blocks of DNA.
What are the components of a DNA nucleotide?
- Deoxyribose sugar
- Organic Base
- Phosphate group
These components are essential for the formation and function of DNA.
What is the orientation of the two DNA strands in the double helix?
The two DNA strands are anti-parallel.
This means one strand runs 5’ to 3’ and the other runs 3’ to 5’.
What is found at the 3’ end and the 5’ end of a DNA strand?
3’ end: Deoxyribose sugar
5’ end: Phosphate group
This orientation is crucial for DNA replication and function.
How are the DNA nucleotides in a strand of DNA joined together?
By strong chemical bonds between the phosphate group of one nucleotide and the deoxyribose sugar of another nucleotide, creating a sugar-phosphate backbone.
This backbone provides structural stability to the DNA molecule.
What type of base pairing occurs between the two strands of DNA?
There is complementary base-pairing between the two strands.
This ensures accurate replication and transcription of genetic information.
How many hydrogen bonds are formed between Adenine and Thymine?
2 weak hydrogen bonds.
This is crucial for the stability of the DNA structure.
How many hydrogen bonds are formed between Cytosine and Guanine?
3 weak hydrogen bonds.
The increased number of bonds contributes to the stability of the DNA structure.
Where is DNA found in eukaryotes?
In linear chromosomes in the nucleus.
Eukaryotes include organisms such as plants, animals, and fungi.
Where is DNA found in prokaryotes?
In circular chromosomes in the cytoplasm and in plasmids.
Prokaryotes include bacteria and do not have a nucleus.
What additional locations contain DNA in eukaryotic cells?
In mitochondria and chloroplasts.
These organelles have their own circular DNA, separate from nuclear DNA.
What role do histone proteins play in DNA organization?
DNA is tightly coiled and packaged with associated histone proteins.
This packaging is essential for DNA compaction and regulation of gene expression.
