2.6 Structure of DNA and RNA Flashcards
Name the organic compounds which are the genetic material of a cell.
Nucleic acids.
What 3 components does each nucleotide have, and how are they drawn?
5-carbon pentose sugar Phosphate group (circle) Nitrogenous base (rectangle)
Which carbon atom is the nitrogenous base attached to?
The 1’- carbon atom (the right)
Which carbon atom is the phosphate group attached to?
The 5’- carbon atom (the left)
What is DNA?
A double stranded form that stores the genetic blueprint for cells.
What is RNA?
A more versatile single stranded form that transfers the genetic information for decoding.
Name the pentose sugar for DNA and RNA.
DNA - deoxyribose
RNA - ribose
Name the base composition for DNA and RNA.
DNA - ATGC
RNA - AUGC
Name the number of strands in RNA and DNA.
DNA - double stranded (two)
RNA - single stranded (one)
Fill in the blank. Nucleic acids are composed of nucleotide monomers which are linked into a single strand via _____ ______.
Condensation reactions.
Where does the phosphate group of one nucleotide attach to on another nucleotide?
It attaches to the sugar of another nucleotide.
Name the bond that forms between two nucleotides.
Phosphodiester bond.
What are the results of condensation reactions in nucleic acids?
Long polynucleotide strands are formed.
How many bonds are between Adenine and Thymine?
Two.
How many bonds are between Guanine and Cytosine?
Three.
What is the term for the two strands of DNA running in opposite directions?
Antiparallel.
Why did Watson and Crick use models when elucidating the structure of DNA?
It allowed them to visualise and assess the viability of potential structures.
Which scientist concluded that ‘DNA is composed of nucleotides made up of a sugar, phosphate and base’?
Phoebus Levene (1919)
Which scientist concluded that ‘DNA is composed of an equal number of purines (A + G) and pyrimidines’?
Erwin Chargaff (1950)
Which scientist concluded that ‘DNA is ordered into a helical structure’?
Rosalind Franklin (1953)
Name the 3 features that Watson and Crick’s model demonstrated.
- DNA strands are antiparallel and form a double helix.
- DNA strands pair via complementary base pairing.
- Outer edges of bases remain exposed.
