2.1.3 Nucleotides and Nucleic Acids Flashcards
What the 4 main types of nucleic acids?
- DNA
- RNA
- ATP
- ADP
What is a nucleic acid made out of?
Polymer of nucleotide monomers
What does a nucleotide contain?
- Pentose monosaccharide
- Phosphate group
- Nitrogenous base
How do nucleotides bond?
Condensation; phosphate (5’) reacts with OH- (3’)
Phosphodiester bond formed
How are nucleic acids broken down?
Hydrolysis
What is the structural difference between DNA and RNA? (3)
- Deoxyribose/ ribose- 1 less O
- Adenine/ Uracil
- Double stranded/ single
Name the 4 bases of DNA
- Thymine
- Cytosine
- Adenine
- Guanine
The Cat Ate Grapes
Which DNA bases are complementary and how many H bonds are formed?
C+G -> 3
A+T -> 2
3 cars in the garage
Which 2 groups of DNA bases are there? Size?
- Pyrimidines- smaller
2. Purines- bigger
How are the polynucleotide chains joined in the DNA helix?
Hydrogen bonding between complimentary bases
Why are the polynucleotide chains in DNA antiparallel?
Chains are in opposite direction
What sugar is in a RNA nucleotide?
Ribose
What sugar is in a DNA nucleotide?
Deoxyribose
What base in DNA is replaced in RNA?
Thymine -> Uracil
Why do cells replicate?
- Growth
2. Repair
What catalyses the ‘unzipping’ of the DNA helix?
DNA helicase
What catalyses the phosphodiester bonds between new nucleotides?
DNA polymerase
Poly -> Polynucleotide
-ase -> Enzyme
What happens, during DNA replication, when the DNA helix is ‘unzipped’?
Free DNA nucleotides in the nucleus complementary pair to the ‘original’ DNA strand- hydrogen bonding
Why is DNA replication semi- conservative?
Two molecules of DNA are produced, each containing an ‘original’ strand and a ‘new’ strand
What experiment confirmed DNA replication to be semi- conservative?
- Free nucleotides of N-15
- 1st gen: half-half of N-15 and N-14
- 2nd gen: half of N-15/N-14 and half of pure N-15
How does a mutation occur during DNA replication?
Free DNA nucleotides match with the wrong bases- incorrect sequence
What is a codon?
3 bases on the DNA/ RNA strand that codes for a specific amino acid
What is a gene? (DNA replication)
Contains all the codon to make an entire protein
Why is the genetic code a degenerate code?
Different combinations of bases can code for the same amino acid