nucleotides and nucleic acids Flashcards
what is a nucleotide made from?
pentose sugar
nitrogenous base
phosphate group
what do all nucleotide elements contain?
C,H,O,N,P
what does a DNA nucleotide contain?
phosphate group
pentose sugar of deoxyribose
base A,T,C,G
made from 2 polypeptide chains
what type of base are adenine and guanine
purine
MISS PURI IS A G
what type of base are thymine and cytosine
pyrimidine
how many carbon nitrogen do purine and pyrimidine have
purine- 2
pyrimidine-1 (smaller)
what does a RNA nucleotide contain?
phosphate group
ribose sugar
A,U,G,C
made from a single polypeptide chain
what are 2 phosphorylated nucleotides?
ADP AND ATP
what bond is between 2 nucleotides joined together
phosphodiester bond
which bases pair together
A AND T
C AND G
how many bonds form between A,T and C,G
A,T=2
C,G=3
Describe semi-conservative replication
1) DNA helicase breaks hydrogen bonds between 2 polynucleotide DNA strands. Helix unzips to form 2 single strands
2)each original single strand acts as a template for a new strand, free floating DNA nucleotides join to the exposed bases on each original template strand by complementary base pairing
3) nucleotides of new strand are joined together by enzyme DNA polymerase. this forms the sugar phosphate backbone. hydrogen bonds form
4)each new DNA molecule contains one strand from the original DNA molecule and one new strand
what are the 3 main types of RNA
messenger RNA-made in nucleus, 3 adjacent bases are called codon, carries genetic code from DNA in the nucleus to cytoplasm
Transfer RNA-in cytoplasm, has amino acid binding site at one end and a sequence of 3 bases called anticodon
ribosomal RNA-forms 2 subunits in a ribosome. the rRNA in the ribosome helps to catalyse the formation of peptide bonds between the amino acids
ribosomal RNA
what is a gene?
a sequence of DNA nucleotides that codes for a polypeptide
what is the genetic code?
the sequence of base triplets in DNA or mRNA, which codes for specific amino acids
non overlapping, degenerate and universal