DNA repair Flashcards

1
Q

DNA damage may be caused by:

A
  1. radiation
  2. environmental conditions
  3. Endogenous reactive oxygen species
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2
Q

A _____ is any heritable (permanent) change in the structure of an organism’s DNA or chromosomes.

A
  • mutation
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3
Q

______ is the result of gene product having less or no function. When the allele has a complete loss of function it is often called a ___ allele (_____ mutation).

A
  • loss of function
  • null
  • amorphic
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4
Q

_______ is a change the gene product such that it gains a new and abnormal function. Sometimes called a ______

A
  • gain of function

- neomorphic

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5
Q

_______ have an altered gene product that acts antagonistically to the normal allele.

A
  • dominant negative, antimorphic mutations
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6
Q

____ are mutations that lead to a phenotype incapable of effective reproduction (e.g., death).

A
  • lethal
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7
Q

Mutations that affect the whole chromosome or genome level include

A
  1. Fragment Deletions/Insertions (gene abberations)
  2. Inversions
  3. Ploidy changes
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8
Q

Mutations that affect the molecular or base pair level include

A
  1. deletions
  2. insertions
  3. substitutions
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9
Q

Molecular mutations are also known as ______

A
  • point mutations
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10
Q

Origins of mutations

A
  1. Erors during DNA replication.
  2. Errors in chromosome alignments & separation during mitosis & meoisis.
  3. Spontaneous chemical changes in base structure.
  4. Induced chemical changes in base structure
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11
Q

_____ cause “transition mutations” where one purine/pyrimidine base pair is replaced with the other purine/pyrimidine base pair (AT with GC)

A
  • tautomeric shifts

ex: AT with GC

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12
Q

A ______ is the replacement of a purine/pyrimidine with a pyrimidine/purine pair

A
  • Transversion

ex: AC with TG

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13
Q

______ use light energy to break the bonds linking pyrimidine rings

A
  • photolyases
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14
Q

In nucleotide excision repair _____, _____ and _____ complete the repair process

A
  • helicase, polymerase and ligase
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15
Q

In methyl-directed mismatch repair ______ and ____ complete the repair

A
  • DNA polymerase 3 and ligase
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16
Q

________ repair and ________ is through homolougous recombination

A
  • Double strand break

- holliday model

17
Q

In _________ the replicated portion of an incompletely replicated chromosome is used as a repair template

A
  • daughter-strand gap repair
18
Q

_________ establishes lysogeny in bacteriophage λ

A
  • Site-specific recombination
19
Q

_____ uses ATP to promote the pairing of homologous DNA sequences

A
  • RECA
20
Q

A _______ is a bacterial transposable element flanked by short repeated sequences

A
  • transposon
21
Q

Gene amplification may occur via unequal _______ (unequal crossover)

A
  • sister-chromatid exchange
22
Q

Single stranded break, thymine dimer, base mismatch and base alkylation can all lead to DNA _____ that can cause ____

A
  • damage

- cancer

23
Q

UV radiation, alkylating agents, bulky hydrocarbons and DNA crosslinking agents can lead to ________

A
  • DNA damage