dna and protein synthesis notes Flashcards
(94 cards)
what are the 3 major functions of DNA?
controls cellular activities, DNA replication, and DNA mutations
DNA carries a ____
code
DNA controls ____
cellular activities
what are encoded wishing the DNA?
genetic instructions (the code)
what is DNA replication?
when DNA makes exact copies of itself, made to be passed onto other cells
explain how DNA mutation has changed species that live on earth?
different combinations of DNA sequences due to mutations and sexual reproduction explain the existence of all different species on earth
DNA is the source _____
of the unity of life
what did life most likely begin as?
a nucleic acid
what are the two types of nucleic acids?
DNA and RNA
the first form of life on earth is thought to be a self-replicating strand of what?
RNA
who discovered the first x-ray data for the DNA structure?
franklin in 1951
who discovered that DNA has a double helix?
james watson and francis crick (bad people)
1953
DNA and RNA are polymers of what?
nucleotides
what is a nucleotide composed of?
- a pentose (5 carbon) sugar (deoxyribose/ribose)
- a phosphate group
- a nitrogenous base
what are the two types of bases?
purines and pyrimidines
which base has a double nitrogen ring structure?
purines
which base has a single nitrogen ring structure?
pyrimidines
what are the two nucleotide bases of purines?
adenine and guanine
what are the three nucleotide bases of pyrimidines?
thymine, cytosine, uracil (RNA ONLY)
DNA is a _____ helix
double
what is linked together to form the double helix of DNA?
a sequence of nucleotides linked together
what are the strands of DNA composed of?
alternating molecules of deoxyribose and phosphate
what is attached to each deoxyribose unit in DNA?
a nitrogenous base
what can the double helix be described as?
a twisted ladder