a1.2- nucleic acids Flashcards
dna
genetic materials for all living organisms
genetic code
universal and shared amongst all living organisms studied
what does a nucleotide consist of
- phosphate group
- deoxyribose
- nitrogenous base
features of phosphate group
- acidic
- negatively charged
location + bond of nitrogenous base
- protected by double helix
- join 2 strands by hydrogen bonds
what is each strand of dna made of
nucleotides
how is double helix formed
- 2 anti-parallel complementary strands
- hydrogen bond holds adjacent sections together based on complementary bases
why cant bindings by gt or ac
different lengths so wont form chemical bonds
length of purines compared to pyrimidines
longer
phosphodiester bonds
- between sugar and phosphate
- forms the sugar-phosphate backbone
what is the genetic code made up of
sequence of bases
why is the nitrogenous bases on the inside
very reactive
- might react and break the double helix structure
y is complementary base pairing important
- acts as a self check mechanism
- ensures mistakes are not made when copying or transcribing dna
y is the use of dna good [2]
- economical
- space: strorage is limitless
> can keep adding nucleotides
- materials used - high diversity of dna sequence
- can use atgc in nay order
structure of eukaryotes dna
dna wraps twice around each nucleosome before moving onto the next one
nucleic acids
continuous chain of covalently bonded atoms in each strand of dna/rna
2 purines
adenine
guanine
3 pyramidine
cytosine
thymine
uracil
supernatant
liquid above solid residue after centrifuge
codons
sequence of three nucleotides which together form a unit of genetic code in a dna or rna molecule
degenerate code
when amino acids can be coded by more than 1 codon
3 stop codons
UAG
AGA
UAA
start codon (amino acid + code)
Met
- coded by AUG
how does codon go to corresponding amino acid
thru translation in the ribosome
direction of dna and rna
5’ to 3’
significance of the directionality of rna/dna
- affect the way enzymes can bind to
- function when bound to the nucleic acids
when does the directionality rna/dna matter
- DNA polymerase during DNA replication
- RNA polymerase during transcription
- ribosome during translation
what parts of the nucleotides are joined tgt to make nucleic acids
pentose sugars with phosphates
