Gene Mutation & DNA repair

Question 1

Mutations

Answer 1

Heritable change in genetic material

Question 2

_________ changes the DNA sequence

Answer 2

Mutations

Question 3

What are some advantageous of mutations?

Answer 3

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

Question 4

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

Answer 4

Gene mutations

Question 5

What are the 3 different types of gene mutations?

Answer 5

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

Question 6

Point mutation

Answer 6

Change in a single base pair in DNA

Question 7

Base substitution (type of point substitution)

Answer 7

When one base is substituted for another

Question 8

Transition

Answer 8

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)

Question 9

Transversion

Answer 9

Purines & pyrimidines are interchanged

Question 10

___________ can alter the coding sequences of a gene

Answer 10

Gene Mutation

Question 11

Silent mutations

Answer 11

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)

Question 12

Missense mutation

Answer 12

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

Question 13

Nonsense mutation

Answer 13

Involves a change from a normal codon to a stop condon

Question 14

Frameshift mutations

Answer 14

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

Question 15

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

Answer 15

Frameshift

Question 16

Mutation in noncoding sequences can affect ______________

Answer 16

Gene expression

Question 17

Up promter mutation

Answer 17

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

Question 18

Down promoter mutations

Answer 18

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

Question 19

Coding regions

Answer 19

Is the protein

Question 20

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

Answer 20

Deals with the expression level

Question 21

Mutations can occur in __________ of somatic cells

Answer 21

Germs - Line

Question 22

Germ cell mutation

Answer 22

Occurs during meiosis & is heritable

Question 23

Somatic cell mutations

Answer 23

Occurs during mitosis & not heritable

Question 24

Mutations are ____________

Answer 24

Mostly bad

Question 25

_____________ can detect, remove, or replace mutations

Answer 25

DNA repair

Question 26

What are the types of DNA repairs?

Answer 26

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

Question 27

Direct repair

Answer 27

Reverse covalent bonds

Question 28

Photolyase

Answer 28

Repairs thymine dimers or splits (breaks) the dimer

Question 29

Alkytransferase

Answer 29

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

Question 30

Glycosylase (Involves in Base excision repair)(BEA)

Answer 30

Detects abnormal base & cuts it out

Question 31

Endonuclease (Involved in Base excision repair BEA)

Answer 31

Cuts the back bone

Question 32

DNA polymerase in (base excision repair (BEA) )

Answer 32

Removes abnormal segments & fills in the gap

Question 33

DNA ligase (in Base excision repair (BEA) )

Answer 33

Seals the remaining gap

Question 34

What mutation is the worst mutation?

Answer 34

Non-sense mutation (but not always bad)

Question 35

CCR5 mutation

Answer 35

Deletes CCR5 & is HIV resistant therapy

Question 36

LPA mutation

Answer 36

Decrease heart disease

Question 37

PCSK9 heterozygous mutation

Answer 37

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

Question 38

Mutation can increase

Answer 38

1. Endurance 2. Flexibility 3. Strength 4. Wakefulness 5. Durability

Question 39

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

Answer 39

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

Question 40

Xerodermine Pigmentosum (XP)

Answer 40

Is an NER disease & is sun sensitive

Question 41

Mismatch repair steps

Answer 41

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

Question 42

Double stranded break

Answer 42

Can lead to translocation (have 100 break per day)

Question 43

What are the 2 types of repairs for broken chromosomes?

Answer 43

1. Homologous recombination (HRR) | 2. Non-homologous end joining (NHEJ)

Question 44

Homologous recombination repair steps

Answer 44

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

Question 45

Non-homologous end joining process

Answer 45

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

Question 46

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

Answer 46

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

Question 47

CRISPR

Answer 47

Breaks chromosomes & causes mutation

Question 48

What are the steps in base excision repair?

Answer 48

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