Nucleic Acids Flashcards
Degenerate
If amino acids have more than one triplet that codes for it.
Universal
The same four bases used in all organisms.
Mutations
When bases are deleted or changed. This can change the overall protien created.
mRNA
Attatches onto template strand of DNA. Uses Uracil instead of thymine.
tRNA
Transfer RNA. It has an anticodon that attatches to each triplet on an mRNA. The tRNA also carries an amino acid. This amino acid is specific to the codon that attatches to the anticodon.
3 componants of a nucleotide in DNA
- nitrogenous base, ATCG
- sugar deoxyribose
- a phosphate group
Purines
- double carbon ring structure
- Adenine
- guanine
Pyrimidines
- single carbon ring structure
- cytosine
- thymine
5’ end. 3’ end.
If the 5th carbon in wach deoxyribose is pointing up, it’s the five end. If the 3rd carbon is pointing up, it’s the three end.
Structure of RNA
- ribose sugar
- nitrogenous base (GCAU)
- a phosphate
ATP structure
- Adenine nitrogenous base
- 3 phosphates
- ribose sugar
What bond links nucleotides together?
Phosphodiester bond
Introns and exons
The parts of pre mRNA. Exons are kept, introns are SPLICED. HA HA
Process of removing introns?
Splicing
What is the mRNA called before spilcing?
pre-mRNA
what is mRNA called after SPLICING?
mature mRNA
what is a nucleosome?
A bunch of histons wrapped in DNA.
What do nucleosomes create?
They coil to create chromatin. chromatin makes up chromosomes.
How does atp release energy?
A small amount of energy is required to break the bind holding the last phosphate group.
A large amount of energy is released when the liberated phosphate group undergoes reactions involving bond formation.
Properties of ATP (5)
- small
- water soluble (energy requiring processes happen in aqueous environments)
- large enough to be useful in cellular reactions but not so large that energy is wated as thermal energy.
- releases energy in small quantities
- easily regenerated.
3 main types of activity in cells…
- synthesis
- transport
- movement
what is phosphorylation
the reattaching of a phosphate molecule to a molecule of ADP, releasing a water molecule. this is, therefore, a condensation reaction
ATP is un..
unstable
What happens at the beginning of translation…
The mRNA binds to the small subunit of the ribosome at its start codon.
Ribosome structure
Two subunits, one large and one small, each made up of equal amounts of protein.
Two roles of the rRNA
- maintains stability of the protein synthesis sequence.
- biochemical tole in catalysing the reaction
What is the 5’ 3’ strand called???
the sense strand
What is the 3’ 5’ end called???
the antisense strand
Which strand acts as the template strand???
the antisense strand
The sense strand is also the…
coding strand
4 bases, how many different codons can there be?
64 codons (combinations of the 4 bases)
how many start codons are there?
1 (ATG)
function of introns
seperating genes
how many bases can fit in the ribosome at a time (translation)?
6
how is the amino acid bound to the tRNA molecule?
using ATP
why do we call strands 5” 3”?
if the 5th carbon is pointing upwards
Which carbons form covelant bonds in phosphodiester linkage?
3 rd and 5 th
What can hydrolysis of ATP be used for?
- releasing inorganic phosphate to phosphorylate other compounds
- coupling to other reactions that need energy
what is the name of the enzyme that resynthesises ATP during photosynthesis and respiration?
ATP synthase
differences in structure between tRNA and DNA?
- mRNA has more nucleotides
- mRNA is straight tRNA is folded
- mRNA has no paired bases
what does a stop codon code for?
nothing / no amino acid
