Ch 13 DNA and its Role in Heredity
transformation
transfection – the insertion of recombinant DNA into animal cells
transgenic organism – an organism engineered to contain, and usually express, a gene from
another organism
genetic marker – a DNA sequence such as a single nucleotide polymorphism whose presence is
correlated with the presence of other linked genes on that chromosome; in cloning, a gene of
identifiable phenotype that indicates the presence of another gene, DNA segment, or
chromosome fragment
antiparallel strands – molecular orientation in which a molecule / parts of a molecule have
opposing directions
complementary base pairing – AT / TA (AU in RNA), CG / GC pairing of bases in double-stranded
DNA, in transcription, and between tRNA and mRNA
5’ and 3’ end
- 5’ end – end of DNA or RNA strand that has a free phosphate group at the 5’ carbon of
the sugar (deoxyribose or ribose)
- 3’ end – end of a DNA or RNA strand that has a free hydroxyl group at the 3’ carbon of
the sugar (deoxyribose or ribose)
major / minor groove
models of DNA replication
- semiconservative replication – the way in which DNA is synthesized; each of the 2
partner strands in a double helix acts as a template for a new partner strand; after
replication, each double helix consists of 1 old and 1 new strand
,origin of replication (ori) – DNA sequence at which helicase unwinds the DNA double helix and
DNA polymerase binds to initiate DNA replication
replication fork – point at which a DNA molecule is replicating; the fork forms by the unwinding
of the parent molecule
template strand – molecule / surface on which another molecule is synthesized in
complementary fashion, as in the replication of DNA
DNA polymerase – any of a group of enzymes that catalyze the formation of DNA strands from a
nucleic acid template
primase – an enzyme that catalyzes the synthesis of an RNA primer for DNA replication
primer – strand of nucleic acid, usually RNA, that is the necessary starting material for the
synthesis of a new DNA strand, which is synthesized from the 3’ end of the primer
DNA helicase – enzyme that unwinds the double helix
leading strand – in a DNA replication fork, the daughter strand that is synthesized continuously
at its 3’ end
lagging strand – in a DNA replication fork, the daughter strand that is synthesized in
discontinuous stretches; exposed 3’ end gets farther away from fork, creating gap; requires
Okazaki fragments
Okazaki fragments – newly formed DNA making up the lagging strand in DNA replication; after
primer removal, DNA ligase links these fragments together to make a continuous strand
, DNA ligase – enzyme that seals breaks in DNA strands during replication and recombination
processive – referring to an enzyme that catalyzes many reactions each time it binds to a
substrate, as DNA polymerase does during DNA replication
telomeres – repeated DNA sequences at the ends of eukaryotic chromosomes
telomerase – an RNA dependent DNA polymerase that catalyzes the addition of telomeric
sequences lost from chromosomes during DNA replication
proofreading – during DNA replication, a mechanism that excises a base that is incorrectly
inserted across from the template and inserts the correct base
DNA repair mechanisms
- mismatch repair – mechanism that scans DNA after it has been replicated and corrects
any base-pairing mismatches
- excision repair – DNA repair mechanism that removes damaged DNA and replaces it
with the appropriate nucleotides
polymerase chain reaction (PCR) – enzymatic technique for the rapid production of millions of
copies of a particular stretch of DNA where only a small amount of the parent molecule is
available
Circumstantial evidence indicates that genetic material is DNA
- new dye that could bind specifically to DNA
- confirmed to be an important component of nucleus and chromosomes
- present in the right amounts; twice that in reproductive cells
- DNA varied among species
DNA from one type of bacterium genetically transforms another type
transformation
transfection – the insertion of recombinant DNA into animal cells
transgenic organism – an organism engineered to contain, and usually express, a gene from
another organism
genetic marker – a DNA sequence such as a single nucleotide polymorphism whose presence is
correlated with the presence of other linked genes on that chromosome; in cloning, a gene of
identifiable phenotype that indicates the presence of another gene, DNA segment, or
chromosome fragment
antiparallel strands – molecular orientation in which a molecule / parts of a molecule have
opposing directions
complementary base pairing – AT / TA (AU in RNA), CG / GC pairing of bases in double-stranded
DNA, in transcription, and between tRNA and mRNA
5’ and 3’ end
- 5’ end – end of DNA or RNA strand that has a free phosphate group at the 5’ carbon of
the sugar (deoxyribose or ribose)
- 3’ end – end of a DNA or RNA strand that has a free hydroxyl group at the 3’ carbon of
the sugar (deoxyribose or ribose)
major / minor groove
models of DNA replication
- semiconservative replication – the way in which DNA is synthesized; each of the 2
partner strands in a double helix acts as a template for a new partner strand; after
replication, each double helix consists of 1 old and 1 new strand
,origin of replication (ori) – DNA sequence at which helicase unwinds the DNA double helix and
DNA polymerase binds to initiate DNA replication
replication fork – point at which a DNA molecule is replicating; the fork forms by the unwinding
of the parent molecule
template strand – molecule / surface on which another molecule is synthesized in
complementary fashion, as in the replication of DNA
DNA polymerase – any of a group of enzymes that catalyze the formation of DNA strands from a
nucleic acid template
primase – an enzyme that catalyzes the synthesis of an RNA primer for DNA replication
primer – strand of nucleic acid, usually RNA, that is the necessary starting material for the
synthesis of a new DNA strand, which is synthesized from the 3’ end of the primer
DNA helicase – enzyme that unwinds the double helix
leading strand – in a DNA replication fork, the daughter strand that is synthesized continuously
at its 3’ end
lagging strand – in a DNA replication fork, the daughter strand that is synthesized in
discontinuous stretches; exposed 3’ end gets farther away from fork, creating gap; requires
Okazaki fragments
Okazaki fragments – newly formed DNA making up the lagging strand in DNA replication; after
primer removal, DNA ligase links these fragments together to make a continuous strand
, DNA ligase – enzyme that seals breaks in DNA strands during replication and recombination
processive – referring to an enzyme that catalyzes many reactions each time it binds to a
substrate, as DNA polymerase does during DNA replication
telomeres – repeated DNA sequences at the ends of eukaryotic chromosomes
telomerase – an RNA dependent DNA polymerase that catalyzes the addition of telomeric
sequences lost from chromosomes during DNA replication
proofreading – during DNA replication, a mechanism that excises a base that is incorrectly
inserted across from the template and inserts the correct base
DNA repair mechanisms
- mismatch repair – mechanism that scans DNA after it has been replicated and corrects
any base-pairing mismatches
- excision repair – DNA repair mechanism that removes damaged DNA and replaces it
with the appropriate nucleotides
polymerase chain reaction (PCR) – enzymatic technique for the rapid production of millions of
copies of a particular stretch of DNA where only a small amount of the parent molecule is
available
Circumstantial evidence indicates that genetic material is DNA
- new dye that could bind specifically to DNA
- confirmed to be an important component of nucleus and chromosomes
- present in the right amounts; twice that in reproductive cells
- DNA varied among species
DNA from one type of bacterium genetically transforms another type
