Gene Mutation & DNA repair Flashcards

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1
Q

Mutations

A

Heritable change in genetic material

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2
Q

_________ changes the DNA sequence

A

Mutations

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3
Q

What are some advantageous of mutations?

A

Can cause allelic variation & evolution where if detrimental it can be repaired

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4
Q

____________ are molecular changes in the DNA sequence of a gene (changed a nucleotide in DNA)

A

Gene mutations

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5
Q

What are the 3 different types of gene mutations?

A
  1. Substitution (base substitution which is a type of point mutation)
  2. Deletion
  3. Insertion
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6
Q

Point mutation

A

Change in a single base pair in DNA

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7
Q

Base substitution (type of point substitution)

A

When one base is substituted for another

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8
Q

Transition

A

A change from one pyrimidine to another pyrimidine base (like C to T) or from one purine base to another purine base (like A to G)

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9
Q

Transversion

A

Purines & pyrimidines are interchanged

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10
Q

___________ can alter the coding sequences of a gene

A

Gene Mutation

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11
Q

Silent mutations

A

Are mutations that don’t change the amino acid that produce (but does change the codon but still get the same amino acid ) (Genetic material redundant)

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12
Q

Missense mutation

A

Are base substitution that does change the amino acid that is produced (can have minor or major effects)(ex. sickle cell disease)

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13
Q

Nonsense mutation

A

Involves a change from a normal codon to a stop condon

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14
Q

Frameshift mutations

A

Involves the insertion or deletion of a number of nucleotides that are not multiples of 3 or dividably by 3 (group of 3)

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15
Q

_____________ shifts the reading frame causing a new reading frame which changes protein sequence after it

A

Frameshift

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16
Q

Mutation in noncoding sequences can affect ______________

A

Gene expression

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17
Q

Up promter mutation

A

Promoters mutation that increase transcription (makes a sequence more like consence sequence)

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18
Q

Down promoter mutations

A

Decreases transcription rate & causes a promoter to become less like consensus

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19
Q

Coding regions

A

Is the protein

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20
Q

Noncoding regions contains the promoter & ______________ & the regulatory sequence is behind the promoter

A

Deals with the expression level

21
Q

Mutations can occur in __________ of somatic cells

A

Germs - Line

22
Q

Germ cell mutation

A

Occurs during meiosis & is heritable

23
Q

Somatic cell mutations

A

Occurs during mitosis & not heritable

24
Q

Mutations are ____________

A

Mostly bad

25
Q

_____________ can detect, remove, or replace mutations

A

DNA repair

26
Q

What are the types of DNA repairs?

A
  1. Direct repair
  2. Base excision & nucleotide excision repair
  3. Mismatch repair
  4. Homologous recombination repair
  5. Non-homologous end joining
27
Q

Direct repair

A

Reverse covalent bonds

28
Q

Photolyase

A

Repairs thymine dimers or splits (breaks) the dimer

29
Q

Alkytransferase

A

Repairs alkylated base (methyl or ethyl group) & transfers alkyl groups to itself

30
Q

Glycosylase (Involves in Base excision repair)(BEA)

A

Detects abnormal base & cuts it out

31
Q

Endonuclease (Involved in Base excision repair BEA)

A

Cuts the back bone

32
Q

DNA polymerase in (base excision repair (BEA) )

A

Removes abnormal segments & fills in the gap

33
Q

DNA ligase (in Base excision repair (BEA) )

A

Seals the remaining gap

34
Q

What mutation is the worst mutation?

A

Non-sense mutation (but not always bad)

35
Q

CCR5 mutation

A

Deletes CCR5 & is HIV resistant therapy

36
Q

LPA mutation

A

Decrease heart disease

37
Q

PCSK9 heterozygous mutation

A

Causes overdominance (heterozygous advantage) & blocks PCSK9 protein by 50%

38
Q

Mutation can increase

A
  1. Endurance
  2. Flexibility
  3. Strength
  4. Wakefulness
  5. Durability
39
Q

What are the step in nucleotide excision repair (NER)?

A
  1. Uvr A/B looks for mutation (thymine dimer)
  2. Uvr A/B finds the mutation
  3. Uvr A leaves & Uvr C binds
  4. UrvC cuts DNA & Uvr D removes damaged region
  5. DNA polymerase fills in the gap with new region & ligase seals the cuts
40
Q

Xerodermine Pigmentosum (XP)

A

Is an NER disease & is sun sensitive

41
Q

Mismatch repair steps

A
  1. Chargaff rule - A binds to T & G binds to C
  2. DNA polymerase proofreads in the 3’ to 5 direction & if its detects a mismatch can repair it
  3. MutS finds mismatch & MutH/L binds to it
  4. MutH cuts new strand
  5. DNA polymerase fills gap ligase seals gap
42
Q

Double stranded break

A

Can lead to translocation (have 100 break per day)

43
Q

What are the 2 types of repairs for broken chromosomes?

A
  1. Homologous recombination (HRR)

2. Non-homologous end joining (NHEJ)

44
Q

Homologous recombination repair steps

A
  1. Double strand break
  2. End processing
  3. Strand exchange
  4. DNA synthesis
  5. Ligation
45
Q

Non-homologous end joining process

A
  1. Double stranded
  2. End binding protein bind to DNA strand
  3. Repair proteins repair break
  4. Gap filling & ligation
46
Q

Which repair system for broken chromosome is used more often & safer?

A

Non-homologous because not dividing sister chromatids(used 80% of the time to fixed double strand break)

47
Q

CRISPR

A

Breaks chromosomes & causes mutation

48
Q

What are the steps in base excision repair?

A
  1. Glycosylase recognize abnormal base & break the bond between the base & sugar phosphate back bone
  2. Endonuclease recognizes the missing base & breaks (cut) the DNA backbone near the missing base region
  3. DNA polymerase removes the damaged region & replaces it with a new region & fills in the gap with the region
  4. Ligase seals the little cuts in the backbone of the new region