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
Which codons aren’t for amino acid production?
3 Stop codons
What codon codes for 2 different things?
AUG: Start/ Read and Methionine
How are genetic mutations prevented in DNA replication? Accuracy is maintained? (2)
- Semi- conservative replication- original strand
2. DNA polymerase can proofread and correct
Why is RNA essential for protein synthesis?
DNA too large to leave nuclear envelope
What is a sense strand, in protein synthesis?
Contains the correct coding for the amino acid sequence (from 5’ to 3’)
What is a anti-sense/ template strand, in protein synthesis? Carbon numbers?
Complementary to the sense strand (from 3’ to 5’)
What happens during transcription of protein synthesis? (3)
- Helicase unzips
- mRNA made from anti-sense strand- RNA polymerase joining
- mRNA leaves through nuclear pore
What happens during translation of protein synthesis? (4)
- mRNA binds to ribosome
- tRNAs with complementary anticodons bind to mRNA’s specific codons- 2 at a time
- Amino acids form peptide bonds- Peptidyl transferase
- ‘Stop’ codon- can go to golgi for modification
What is tRNA?
Type of RNA in ribosome; contains specific anti-codons to translate mRNA to synthesis proteins
What is an anti-codon?
A sequence of 3 bases on a tRNA complementary to a specific codon on mRNA; carries specific amino acid
Where does the peptidyl transferase come from?
Enzymatic component of ribosome
ATP and ADP are ____ nucleotides
Phosphorylated
What is ATP short for?
Adenosine triphosphate
What is ADP short for?
Adenosine diphosphate
What’s the structure of ATP?
- Nitrogenous base- Adenine
- Pentose sugar- Ribose
3 3 inorganic phoshate groups
What’s the difference between ATP and ADP?
ADP has 2 phosphates instead of 3
How does ATP release energy?
Hydrolysis
ATP + H20 -> ADP + energy
Why is ATP a bad long-term energy store?
Instable phosphate groups
Why is ATP a good immediate energy store?
Easily regenerated
Why does the ATP hydrolysis reaction have a low activation energy?
Negatively charged phosphate groups rebel and are unstable
What are useful features of ATP? (4)
- Small- in/out cells
- Water soluble- aqueous environments
- Energy released in small quantities- not wasted
- Easily regenerated- good immediate energy
What reaction is ADP to ATP?
Condensation
Phosphorylation
