Nucleic Acids Flashcards
What are the 2 best known nucleic acids?
Ribonucleic acid and deoxyribonucleic acid
What is DNA?
The material that passed on features of organisms from one generation to the next
What does DNA carry?
Genetic information
What are the two most important structural features of DNA?
- Double helix structure
- made up of nucleotides that have 3 basic components
What 3 things make up a nucleotide?
1) a Pentose sugar
2) a phosphate group
3) a nitrogen containing organic base (A, U, C, G, T)
By what kind of reaction is a mono-nucleotide formed?
A condensation reaction.
How do two mono nucleotides join to make a di-nucleotide?
Between phosphate group of one and deoxyribose sugar of one. - via condensation reaction
What bond holds adjacent nucleotides together?
Phosphodiester
What is the structure of RNA?
Single, relatively short polynucleotide chain
What sugar has RNA got?
Ribose
What are RNA’s organic bases?
-Adenine
-Guanine
-Uracil
-Cytosine
What are 3 uses of RNA?
1) transfer genetic information from DNA to ribosomes
2) Make up ribosomes (made of protein and other RNA)
3) Protein synthesis
What bonds form between bases on opposite strands?
Hydrogen bonds
What are the complimentary base pairs?
- A with T(or U in RNA)
- G with C
In DNA, are the quantifies of (A and T) and (G and C) always the same?
Yes
What does the deoxyribose and phosphate group wound around one another (forming the double helix) provide?
A structural backbone
How do the phosphodiester bonds make DNA a stable molecule?
Protects the more chemically reactive organic bases inside the double helix.
How do hydrogen bonds make DNA a stable molecule?
They link the organic base pairs forming bridges between the phosphodiester uprights
What holds the molecule together and also makes it more stable?
Interactive forces between the base pairs that hold the molecule together (base stacking)
What provides evidence for large genetic diversity?
There are an infinite variety of base sequences as there are 3.2 billion base pairs in the DNA of a typical mammalian cell
Why is the adaptation of DNA having a stable structure important? (2)
- Means it can pass through generations
- mutations are repaired so persistent mutations are rare.
Why is the adaptation of DNA having hydrogen bonds important?
The two separate strands are joined so replication can occur by separating strands for protein synthesis.
Why is the adaptation of DNA being very large important?
Can carry immense amounts of genetic information.
Why is the adaptation of DNA having a helical cylinder important?
The base pairs are inside the cylinder so genetic information is protected from being corrupted by outside chemical and physical forces.
Why is the adaptation of DNA’s base pairing important?
Leads to DNA being able to replicate and transfer information as mRNA.
How is the double helix formed?
The hydrogen bonds joining the strands entwine the strands.
Who contributed to the discovery of DNA structure?
James Watson and Francis Crick
