DNA Structure Flashcards
(31 cards)
What is the chromosomes theory of inheritance?
describes the transmission of chromosomes and how chromosomes carry and transmit genetic determinants of traits
What do chromosomes contain?
- DNA, RNA and protein
Experiments that demonstrated DNA as the genetic material:
i. Griffith: Avirulent to virulent bacteria.
ii. Avery, MacLeod & McCarthy: isolting different components of the cell.
iii. Hershey & Chase: Bacteriophage
What is the transforming principle?
DNA is the transforming principle.
What is transformation(Griffith)?
When a normal cell is transformed into a malignant cell.
What is a genetic material?
A genetic material is something that contains information needed to make an organism (information storage)which is then replicated (replication, copied and transmitted (transmission) from parent to offspring and is able to account for variation (variation) of our phenotypic differences. That genetic material is DNA.
What do we mean when we say that DNA and RNA are acidic molecules?
That they release hydrogen ions in solutions and have a negative charge at neutral pH
What are the two types o sugars?
Deoxyribose and ribose
Two groups of bases:
Purine and Pymiridine
Five Bases:
Adenine (A)
Guanine (G)
Thymine (T)
Cytosine (C)
Uracil (U)
What are the purine bases?
Adenine and Guanine
What are the pyrimidine bases?
Thymine, Cytosin and Uracil
What are the common bases found in DNA and RNA?
Adenine, Guanine and Cytosine
Which base is different in both DNA and RNA?
Thymine- DNA
Uracil- RNA
What is a nucleoside?
-The combinaton of ONLY base+ ONLY
a sugar.
A nucleoside is similar to a nucleotide however, they differ in structure because a nucleoside lacks a phosphate group while a nucleotide has a phosphate group.
What makes up a nucleotide:
A base, one or more phosphate groups and a sugar.
Where are the base and phosphates attached to on the sugars?
-The base attaches to the 1’ carbon atom.
-The phosphates attach to the 5’ position.
-The 3’ carbon atoms position is important because it allows the nucleotides to form covalent links with each other. It attaches to the phosphate of the next nucleotide eventually forming a DNA strand
What are nucelotides linked by?
Phosphodiester bonds
How are two nucleotides linked together?
A phosphate connects the 5’ carbon position of one nucleotide to the 3’ carbon of another.
What do the 5’ and 3’ strand end with?
5’ ends with a free phosphate and
3’ ends with a hydroxyl
What forms the backbone of a nucleic strand?
The phosphate and sugar molecules
What is the specific sequence of bases in DNA?
DNA: 5’ - Thymine-Adenine-Cytosine-Guanine-3’ (5’ - TACG - 3’)
(RNA is probably similar; just replace Thymine (T) with Uracil (U))
What is Chargaff’s rule?
The amount of A equals the amount of T and the amoung of G equals the amount of C.
What are the key features in the molecular structure of DNA?
- Two strands of DNA form a double-helix structure.
- The bases in opposite strands ‘hydrogen bond’ following the AT/GC rule.
- The 2 strands are anti-parallel with regards to their 5’ to 3’ directionality.
- There are approximately 10 nucleotides in each turn.
