Nucleic acids Flashcards
What are nuclei acids?
One of the most important groups of biological molecules, best known as ribonucleic acid (RNA) and deoxyribonucleic acid (DNA)
What is the function of nucleus acids?
Important carrying molecules
What is the function of DNA?
Holds genetic information
What is the function of RNA?
It transfers genetic information to ribosomes where proteins are made
Monomer of nucleic acids
Nucleotides
Dimer of nucleic acids
Dinucleotides
Polymer of nucleic acids
Polynucleotides
What are the components in a nucleotide?
•A phosphate group
•A pentose sugar
•Nitrogen containing bases
Component of a DNA nucleotide
•A charged phosphate group
•A 5 carbon pentose sugar which is deoxyribose (A carbohydrate as it’s a sugar)
•One of 4 nitrogen containing bases: Adenine, cytosine, guanine and thymine
Components of a RNA nucleotide
•A charged phosphate group
•A 5 carbon pentose group which is ribose
•One of 4 nitrogen containing bases: Adenine, cytosine, guanine or uracil
What do all components together form?
They create a sugar phosphate backbone
Formation of dinucleotides
Joined via condensation reactions between phosphate group’s 5 prime end of one nucleotide and the ribose (RNA) or deoxyribose (DNA) 3 prime end forming a phosphodiester bond
Reactions involving DNA nucleotide are catalysed by…
DNA polymerase
Reactions involving RNA nucleotides are catalysed by…
RNA polymerase
What does DNA/RNA polymerase do to bonds?
Secure and solidify the phosphodiester bonds of the sugar phosphate backbone
What are the bonds within nucleotide polymers?
A phosphodiester bonds
What is the other product of condensation reactions between nucleotides?
Water molecules - 1 for each condensation reaction
If more mononucleotides are added via condensation it forms a…
Polynucleotide
What do polynucleotides result in?
Many phosphodiester bonds forming
What is the importance of many phosphodiester bonds being formed?
Creates the sugar phosphate backbone of Nucleic acids which is stable and strong
What direction can nucleotides only be added in?
ONLY added in a 5’-3’ direction by DNA polymerase
What is the structure of DNA?
A double helix with two polynucleotide chains held together by (weak) hydrogen bonds between specific complementary base pairs
Who put forward the double helix structure?
Watson & Crick
What hand is the helix structure?
Right handed
What is the 5’ (prime) end?
The phosphate end
What is the 3’ (prime) end?
The carbon sugar end
What are the DNA strands opened up by?
DNA helicaese
How are Adenine and Thymine bonded?
2 hydrogen bonds
How are Cytosine and Guanine bonded?
3 hydrogen bonds
What direction do the 2 polynucleotides run in?
Opposite directions which means they are antiparallel
What is 5’ - 3’ is important in?
DNA replication and when making proteins
What is the function of DNA?
To hold genetic information
3.w billion base pairs spread over … chromosomes in each cell nucleus?
23 chromosomes
What is a gene?
A section of DNA which codes for (polypeptide) proteins
What’s a chromatid?
Half a chromosome
What makes organisms DNA different?
The DNA base sequence
What is the purpose of the sugar-phosphate backbone and double helix structure?
1) Provides strength and stability
2) Protects information codes in the bases and hydrogen bonding between bases
What is the purpose of DNA being a longer molecule?
This means it’s can store a lot of information
What is the purpose of a helix structure?
It makes it compact
What is the purpose of base sequences?
It allows it to code for amino acids and therefore proteins
What is the purpose of DNA being double stranded?
Allows semi-conservative replication because each strand can act as a template
What is the purpose of complementary base pairing A-T and C-G?
Allows for accurate replication
What is the purpose of (weak) hydrogen bonds between bases?
Easily broken and separation of strands for semi-conservative replication
What is the purpose of many hydrogen bonds in the whole molecule?
To make it a strong and stable molecule
In chargaffs base pairing rule which bases have equal amounts?
Adenine = Thymine
Cytosine = Guanine
What does pyrimidine mean?
1 ring
What does purine mean?
2 rings
Which bases are pyrimidine?
Cytosine and Thymine
Which bases are purine?
Adenine and Guanine
