2.1.3 Flashcards
What’s five elements do you all nucleic acids have?
Carbon Hydrogen Oxygen Nitrogen Phosphorus
What are nucleotides formed of?
- Phosphate
- Pentose sugar
- Nitrogenous base
What is the phosphate group?
Acidic inorganic molecule with the formula PO4, and a charge of two minus
How are nucleotides linked together?
Through condensation reactions.
Making polynucleotides
Where on the pentose sugar is the base and phosphate group joined
?
- Base is attached to the first carbon
- phosphate group is attached to the fifth carbon
What is bond is formed between nucleotides?
Phosphodiester bonds
Where are the phosphodiester bonds formed when linking the nucleotides together?
The phosphate group at the fifth carbon covalently bonds with the OH group at the third carbon
What’s the difference between a deoxyribose sugar and a ribose sugar?
On the second carbon the deoxyribose sugar has one less oxygen than Ribose
What are pyrimidines?
-Smaller bases
Single carbon ring structures
Give two examples of pyrimidines
Thymine and cytosine
What are purines?
-Larger bases
Double carbon ring structures
Give two examples of purines.
Adenine and guanine
How many hydrogen bonds are formed between complimentary bases?
Thymine and Adenine: two hydrogen bonds
Cytosine and guanine: three hydrogen bonds
Why is DNA antiparallel?
Because the two parallel strands run in opposite directions
What is complimentary base pairing?
Small pyrimidine always bonds to large purine
A and T
C and G
What is ATP?
Adenine triphosphate Formed of: -adenine -ribose -three phosphate groups
How are the phosphate groups in ATP joint?
By two high energy bonds
How does ATP become ADP?
It can be hydrolysed to release adenine diphosphate
What is the enzyme used to catalyse the hydrolysis of ATP?
ATPase
What is produced from the hydrolysis of ATP?
ADP
Pi
30kJ/mol
What is semiconservative replication?
Double helix unwinds
Free DNA nucleotides pair up with complimentary bases.
New nucleotides join adjacent nucleotides
Why is it called semiconservative?
Because it’s half the same:
One old strand,
One new strand
What is DNA helicase used for?
It travels along DNA backbone, catalysing reactions that break hydrogen bonds.
It’s the enzyme that unwind and separates DNA strands
What is DNA polymerase used for?
It catalyse the formation of phosphodiester bonds between nucleotides
What is mutation?
Incorrect sequence
Not always match exactly
(the DNA)
What is the genetic code
DNA that codes for sequence of amino acids
