DNA Structure Flashcards
straight up easy
What does DNA stand for?
Deoxyribonucleic Acid
To which organic group does DNA belong?
Nucleic Acids
What are organic molecules, and give examples?
Organic molecules contain carbon attached to other elements (except CO and CO₂). Examples: Glucose, amino acids
What is a nucleotide?
The basic building block (monomer) of DNA
What are the components of a DNA nucleotide?
- Deoxyribose sugar (lacks oxygen at carbon 2)
- Phosphate group (attached to carbon 5, gives acidic nature)
- Nitrogen base (attached to carbon 1)
What are the types of nitrogen bases in DNA?
Adenine (A), Thymine (T), Cytosine (C), Guanine (G)
What is the key difference between DNA and RNA nucleotides?
RNA has ribose sugar and uses Uracil (U) instead of Thymine (T)
What are the key features of DNA polymer structure?
- Double-stranded, connected via hydrogen bonds
- Complementary base pairing rules: A ↔ T (2 bonds), C ↔ G (3 bonds)
- Anti-parallel strands: 5’ → 3’ and 3’ → 5’
What bond links nucleotides in DNA?
Phosphodiester bond
What gives DNA its double helical shape?
The twist every 10 bases
How do purines and pyrimidines pair in DNA?
Purines (Adenine, Guanine) pair with pyrimidines (Cytosine, Thymine) for stability
Name the key figures in the discovery of DNA structure
- Erwin Chargaff: Observed A = T and G = C
- Rosalind Franklin: X-ray diffraction revealed DNA’s helical structure
- Watson & Crick: Built 3D DNA model, Nobel Prize winners
List the differences between DNA and RNA polymers
DNA: Double-stranded, deoxyribose sugar, nitrogen bases (A, T, C, G), larger
RNA: Single-stranded, ribose sugar, nitrogen bases (A, U, C, G), smaller
What is the size comparison between DNA in eukaryotic and prokaryotic cells?
Eukaryotic DNA is 10x larger. Human DNA stretches to ~2m; bacterial DNA to ~0.25cm
Compare prokaryotic and eukaryotic DNA
Prokaryotic: Circular chromosomes, naked DNA, in cytoplasm
Eukaryotic: Linear chromosomes, associated with histones, in the nucleus
