Stucture Of DNA Flashcards
WHAT are the 3 components of a nucleotide?
A Deoxyribose sugar
A phosphate group
A nitrogenous base
What is a nucleoside?
A molecule consisting of :
A deoxyribose sugar bonded to a
Nitrogenous base
WITHOUT a phosphate group
How is a nucleotide different from a nucleoside?
A nucleotide has a phosphate group attached to the nucleoside
What are the nitrogenous bases found in DNA?
Adenine (A)
Thymine (T)
Guanine (G)
Cytosine (C)
What type of bond connects the nitrogenous bases between the 2 strands of DNA?
Hydrogen bonds
How many hydrogen bonds connects the nitrogenous Adenine (A) + Thymine (T)
2 Hydrogen Bonds
How many hydrogen bonds connects the Guanine (G)+ Cytosine (C)
3 Hydrogen bonds
Describe the orientation of the 2 DNA strands
The 2 strands run in opposite directions (antiparallel); one strand runs 5’ to 3’ + the other runs 3’ to 5’
Shape of DNA molecule
Double helix - 2 strands coiled around each other
What are the major + minor grooves in DNA?
Double helix has 2 grooves; major+ minor, which are lined with H bond donors + acceptors + provide sites protein binding
Why are the major + minor grooves important?
They allow proteins to interact with specific DNA sequences - crucial for transcription + replication
What allows certain molecules to intercalate between DNA bases?
Flat, aromatic molecules can insert between the stacked bases, distorting the DNA structure + affect biological functions
Where do alkylating agents commonly target DNA bases?
Alkylating agents often target the N7 position of Guanine (G) + the N3 position of Adenine (A) - disrupting normal base pairing
What’s effect does alkylating have on DNA structure?
It can lead to mutations, DNA strand breaks, and interference with DNA replication + transcription
What stabilises the DNA double helix
Hydrogen bonding between bases + hydrophobic interactions among the stacked bases
