unit 1.2: structure and function of DNA Flashcards
(15 cards)
what is DNA
inherited
genetic material of living things
located in the nucleus
long chemical sequence that contains all genetic information needed for the next generation
chemical sequence varies, called the genotype
what are DNA nucleotides comprised of
deoxyribose sugar
phosphate
organic base
how are nucleotides joined
sugar to phosphate chemical bonds
what are the 4 bases in DNA
adenine
thymine
guanine
cytosine
what is the structure of DNA
anti parallel double helix
how are the 2 DNA strands held together
by hydrogen bonds
what are the stages of DNA replication
stage 1: DNA unwinds and unzips
stage 2: primers attach (anneal) to 3’end
stage 3: DNA (taq) polymerase adds nucleotides in a 3’-5’end direction
how is DNA replicated on the leading strand
continuously
how is DNA replicated on the lagging strand
in fragments
how are fragments sealed
by an enzyme called ligase
what must the nucleus contain for DNA replication to occur
DNA (template)
primers
a supply of the 4 nucleotides
DNA polymerase and ligase enzymes
a supply of ATP
what are the stages in PCR
stage 1: heated to 92-98°C DNA unwinds and unzips
stage 2: cooled to 55°C-65°C primers added to 3’end
stage 3: heated to 70°-80°C for DNA polymerase to replicate
what is a primer
complementary short strand of nucleotides for DNA polymerase to add on to
what are the 5 requirements for PCR
DNA
primers
supply of nucleotides
pH buffer
Mg2+ heat tolerant DNA polymerase co-factor
what are the practical applications of PCR
settling paternity disputes
solving crime
diagnosing genetic disorders
