A 1.2 Nucleic Acids Flashcards
each nucleotide consists of:
a pentose sugar, a phosphate, and a base
nucleotides in a strand of DNA or RNA are linked by
covalent bonds
The formation of RNA is a
condensation reaction because water is produced when the sugar bonds to the phosphate
each strand of DNA has a
phosphate backbone
complementary base pairs in DNA
A-T
C-G
DNA strands are
antiparallel, run in opposite directions
what’s the overall shape of a DNA molecule
double helix
3 differences between RNA and DNA
- The pentose is ribose in RNA but deoxyribose on DNA
2.DNA has the base Thymine, but RNA has Uracil instead
3.RNA usually has one strand of nucleotides but DNA usually has 2
complementary base pairing has roles in
DNA replication, translation, and transcription
DNA replication
allows sequences of DNA to be copied accurately, so the genetic information of a cell can be passed to daughter cells
Transcription
Messenger RNA (mRNA) carries the base sequence of a protein-coding gene to the ribosome
Translation
ribosomes link codons to anticodons by complementary base pairing allowing the base sequence of every codon to be translated into a specific amino acid
diversity in DNA base sequences is
endless
total # of codons
64
total # of amino acids
20
universitality of the genetic code suggests
all life evolved from a common ancestor
Nucleotides are added in which direction
5’ to 3’ direction
when a new strand of DNA or RNA is being constructed a nucleotide is added
to the pentose at the 3’ end
purine bases
adenine and guanine
pyrimidine
cytosine and thymine
nucleosomes are
disc-like structures used by eukaryotes to package DNA into condensed chromosomes
each nucleosomes has
a core of 8 histone proteins
