Chapter 12 - DNA Flashcards
What are nucleotides and what are they made of?
They are the units that make up DNA. They are made of a 5-carbon sugar, a nitrogen base, and phosphate.
What is another name for a 5-carbon sugar?
Deoxyribose
What are the four types of nitrogenous bases?
Adenine, Guanine, Cytosine, and Thymine
What are Purines?
The adenine and guanine nitrogenous pairs;
These have two rings in their structure.
What are pyrimidines?
The cytosine and thymine nitrogenous pairs;
These have only one ring in their structure.
What is the backbone of a DNA chain formed by?
By sugar and phosphate groups inside each nucleotide
What are Chargaff’s rules?
% of [A] = % of [T], and % of [G] = % of [C]
or
% of Adenine = % of Thymine, and % of Guanine = % of Cytosine
In what way if DNA read?
5-3
What is the double-helix structure?
It is like a ladder that is twisted around, or like a spiral staircase.
Between what nitrogenous bases can hydrogen bonds form?
Between Adenine and Thymine, and between Guanine and Cytosine
What kind of bond holds the nitrogenous bases together?
Hydrogen Bonds
What is base pairing, and what did they explain?
This is the pairing of certain bases:
Adenine only bonds with Thymine,
and Guanine only bonds with Cytosine.
This is the principle that explains Chargaff’s rules.
What is chromatin?
Tightly packed DNA and protein that make up chromosomes in eukaryotic cells.
What are histones?
The proteins that DNA wraps around create nucleosomes.
What are nucleosomes?
Groups of histone wrapped in DNA
