DNA Repair And How Mutations Occur- Exam IV Flashcards
Cellular synthesis of new daughter strands of DNA from a parental strand during the S phase of the cell cycled needed for cell division:
DNA replication
Change in DNA sequence from a parental strand to a daughter strand :
DNA mutation
Results in altered gene expression, splicing or altered proteins, generated from the mutated DNA sequence:
Function DNA mutations
Division of the nucleus of a eukaryotic cell, involving condensation of the DNA into visible chromosome, and separation of the duplicated chromosome to form two identical sets.
Mitosis
Special type of cell division that occurs in sexual reproduction. It involves to two successive nuclear divisions with only one round of DNA replication, thereby producing haploid cells from a diploid cell
Meiosis
Changes in the nucleotide sequence of a chromosome that caused disease:
Gene mutation that is responsible for disorders
List the single base pair substitutions that may or may not result in disorders: (5)
- Deletion
- Insertions
- Substitution
- Silence
- Missense
An identifiable segment of DNA sequence with a known physical location on a chromosome and enough variation between individuals.
Genetic marker
The inheritance and co-inheritance of alleles of a given gene in genetic markers can be:
Traced
Can help link an inherited disease with the responsible genes:
Genetic markers
DNA segments close to eachother on a chromosomes tend to be:
Inherited together
Used to track the inheritance of a nearby gene that has not yet been identified but whose approximate location is known
Genetic markers
Genetic markers are used in:
Linkage analysis
Variation between individuals in a population at specific nucleotides in their DNA sequence
Single Nucleotide Polymorphisms
DNA sequence variants of a gene:
Alleles
Mechanisms by which deaminated and depurinated nucleotides are repaired:
Base excision repair
Mechanisms by which pyrimidine dimers are repaired:
Nucleotide excision repair
Formed during homologous recombination which allows DNA strands to switch partners between two DNA double helices
Holiday junction
DNA is under constant pressure to _____ in its DNA sequence
Acquire changes
Most changes in DNA are repaired before they become:
Stable part of DNA passed on to daughter cells
When mutations occur in somatic tissues:
They CANNOT be inherited
Although mutations in somatic tissues CANNOT be inherited, they CAN:
Give rise to diseases such as cancer
When mutations arise in the DNA of gametes:
They will be passed on to the offspring
List the chromosome disorders that can cause genetic disease: (5)
- Rearrangements
- Translocations
- Deletions
- Insertions
- Duplications
Single gene disorders can be: (3)
- Dominant
- Recessive
- Co-dominant
A _____ can give rise to disease:
Single base pair change
Involve large chunks of DNA getting moved around:
Chromosome disorders
Genetic diseases caused by multigenic or gene-environment interactions that can occur and contribute to the formation of a complex trait
Multi factorial or complex disorders
Disorders that involve the X and Y chomosomes
Sex-linked
Mechanisms that cause mutations in the mitochondrial DNA
Mitochondrial Disorders
Somatic mutations are _____, while germline mutations are ______.
Non-inheritable; inheritable
A mutation caused by cigarette smoking resulting in lung cancer would be categorized as:
Somatic mutation
A mutation in the p53 gene typically causing a form of cancer would be categorized as:
Somatic mutation
A mutation that affects the sperm or egg:
Germline mutation
Mutations that can be passed on to your children dependent upon the degree of mutation:
Germline mutation
Mutations that arise naturally during DNA replication (mitosis) or during meiosis:
Spontaneous mutations
mutations caused by exposure of environmental insults:
Induced mutations
Environmental insults that can cause induced mutations include:
Radiation & chemicals
Mutation in which the DNA sequence is altered but results in NO CHANGE in amino acid
Silent mutation
A mutation that results in a SINGLE AMINO ACID CHANGE:
Missense mutation
Mutation resulting in a codon being produced that stops translation and producing a truncated protein:
Nonsense
Nonsense mutations ultimately result in:
Truncated proteins
Mutations that disrupts the reading frame from insertion or deletion of a base:
Framshift
A mutation that results in a glycine being substituted for a valine would be:
Missense mutation
The LRP5 mutation resulting in osteoporosis pseudoglioma syndrome producing truncated proteins is an example of:
Nonsense
A purine getting exchanged for another purine, or a pyramidine being replaced by another pyramidine:
Transition
A purine being substituted for a pyramidine (and pretty sure vice versa):
Transversion
A type of mutation resulting in extra amino acids:
Insertion
A type of mutation resulting in missing amino acids:
Insertion
Maybe you have a single nucleotide deletion or insertion, and since the messenger RNA reads eery 3 nucleotides instead of it reading 1,2,3, its now reading 2, 3, 4 resulting in an altered protein:
Frameshift
A frameshift mutation typically results in:
The wrong amino acid being placed
Cystic fibrosis is due to a:
3 base deletion of Delta F 509 (phenylalanine)
List the types of mutations that don’t necessarily effect the protein being made but may affect the amount of protein or when the protein is being expressed: (4)
- Promotor/Enhancers (nuclear receptors)
- Splice site
- Expanded repeat
- Transposons
Promotors and enhancers are:
Nuclear receptors
Important for regulating the binding of a nuclear receptor to the DNA to tell that gene to be expressed or not expressed:
Promotor
Mutating and important enhancer will:
Change the level of gene expression (amount of protein being made)
A class of sequencing elements found in DNA that are associated with the level or transcription and can be great distances from the start site of transcription:
Enhancers
If you effect the way the RNA gets spliced, you can get a protein with the incorrect information in it: what mutation is this:
Splice site mutation
Where you would typically have a small repeat element of amino acids in DNA that gets exacerbated into an huge repeat element:
Expanded repeat mutation
Hunnington’s disease is caused by:
Expanded repeat mutation
Mobile genetic elements that jump around in the genome and dependent upon where they get inserted can cause changes in gene expression:
Transposons
This is an example of:
Silent mutation
This is an example of:
Missense mutation
Mutations can be designated by: (nomenclature) (5)
- Amino acid change
- Position in genomic DNA
- Position in messenger RNA
- Position in cDNA
- Changes in the protein
What type of system is used in regards to nomenclature of mutations:
Coordinate system
The mutation A1215T would mean alanine at the position ______ is changed to a ______
1215; threonine
Single base bare differences at a specific position in the genome:
SNPs
SNPs occurring within a gene can give rise to:
An allele
How many SNPs are there in the genome?
Millions
We use SNPs to help us identify where _____ might be located.
Allele or trait causing mutations
Why do cells in our body need DNA repair?
To have a mechanism to maintain genetic stability
Maintains the genetic stability that an organism needs for survival requires not only an extremely accurate mechanisms for ______ but also mechanisms for repairing ________.
DNA replication ; accidental lesions
Most spontaneous changes in DNA are ______:
Temporary
Most spontaneous changes in DNA are temporary because:
They are immediately corrected through DNA repair mechansism
The importance of DNA repair is evident from the large investment that cells make in:
DNA enzymes
Following the inactivation of a DNA repair gene there is an:
Increased rate of mutation
DNA of each human cells losers about ______ bases everyday.
5000 purine bases
Purine bases are lost daily due to the the process of:
Deoxyribose hydrolyzation of N-glycosyl linkages
The spontaneous reaction of deoxyribose hydrolyzation of N-glycosyl linkages:
Dupurination
A spontaneous Deamination of cytosine to uracil in DNA occurs at a rate of:
About 100 bases per cell per day
DNA bases are also occasionally damage by an encounter with:
Reactive metabolites
Ultraviolet radiation from the sun can produce a covalent linkage between two adjacent pyrimidine bases in DNA to form:
Thymine dimers
What type of linkage is produced and what bases are affected in DNA when thymine dimers are formed due to UV?
Covalent linkage; Pyrimidines
Hydrolytic attach includes:
Deamination & Depurination
What is the most frequent spontaneous chemical reactions?
Hydrolytic attack
Oxidative damage to the DNA occurs due to the generation of:
Reactive oxygen species
Hydrolytic attacks cleave off a base so you have the deoxyribose base in the chain but:
No base associated with it
About 3% of the C nucleotides in vertebrate DNAs are _____ to help in controlling gene expression
methylated
When teh 5-methyl C nucleotides are accidentally deaminated, they form the natural:
Nucleotide T
When the 5 methyl C nucleotides are accidentally deaminated, they form natural nucleotide T, however this T will be paired with _____ on the opposite strand forming a ____.
G; mismatched base
About 1/3 o f the inherited human disorders are:
Single base mutations
The spontaneous deamination products of A and G are recognizes as unnatural when they occur in DNA and this are:
Readily recognized and repaired
Unnatural bases are recognized and removed by a specific:
DNA glycosylase
The process of unnatural bases being recognized and removed by a specific DNA glycosylase:
Base excision repair
If we have a hydrolytic attack of:
Adenine —->
Guanine —->
Cytosine —->
Thymine—->
Hypoxanthine
Xanthine
Uracil
Thymine means no deamination because there no amino group to remove
Cytosine to uracil in DNA that is estimated to occur at a rate of 100 baes per genome per day:
Deamination
The loss of 5000 A or G bases per day in each daughter cell due to thermal disruption of the N-glycosyl linkages to deoxyribose
Depurination
Thymine dimers are premutagenic lesions that alter the structure of DNA and consequently inhibit ____ & arrest _____.
Polymerase & arrest replication
Dimers may be repaired by _____ or _____.
Photoreactivation or nucleotide excision repair
Unrepaired dimers are:
Mutagenic
How do chemical modifications of nucleotides produces mutation in the case of deamination:
DNA substitution (point mutation)
How do chemical modification of nucleotides produce mutation in the case of depurinations?
DNA deletions
in both Deamination and depurinations, one strand:
Remains unchanged
Process that involves a specific nuclear that carves out a region of the strand that has the thymine dimer, and then removes the damaged DNA and then polymerase and ligase come in to heal it by synthesizing the short stretch that has been removed:
Nucleotide excision repair
Single base pair changes often get repaired by ____ that involves a set of enzymes that are involved in removing the kick and replacing it using the other strand as a template to put back the nucleotide that was removed
Base excision repair
A location in DNA that has neither a purine nor a pyrimidine base:
AP site (apurinic/apyridinic site)
Double stranded breaks can efficiently be repaired by:
- Non-homologous end joining
- Homologous recombination
Non-homologous end joining is considered:
Quick and dirty
In the non-homologous end joining process, you have a Knick in one strand and a Knick and the other strand what happens the nucleotides will be removed to create ____ so there is not there is not extra material there and they can get rejoined
Blunt ends
When a few nucleotides get removed from the sequence through the the quick and dirty process:
Scars
Homologous recombination only occurs in what phases?
S and G2
When the damage of the double stranded break is being repaired using information from the sister pair of the chromosomes for that gene
Homologous recombination
Both non-homologous end jointing and homologous recombination result in the delay of progression from:
G1 to S phase & S to M phases
If each member of a chromosome pair contains the same allele:
Homozygous
If each member of a chromosome pair carries a different allele:
Heterozygous
Generally speaking ____ expresses the most severe phenotype:
Homozygous dominant
in ____ genes you only observe the phenotype in the homozygous state:
Recessive
The phenotype of a _____ gene will be observed in the homozygous or heterozygous state:
Dominant gene
Fancy way of saying you one copy of your gene from mom and one copy of the gene from dad:
Principle of segregation
Sexually reproducing organisms possess genes that occur in pairs and that only one number this pair is transmitted from the offspring:
Principle of segregation
Genes at different loci are transmitted independently:
Principle of independent assortment
Just because you inherit a copy of gene A does mean you’re always going to inherit copy A of another gene
Principle of independent assortment
Mechanisms to:
- Accurately repair doubled strand DNA breaks
- Exchange bits of genetic information
- Assures accurate chromosome segregation during meiosis
Homologous recombination
Homologous recombination has many common features that are found in all cells and its guided by:
DNA base pairing
In homologous recombination, inadvertent jointing of two segments from different chromosomes that results in chromosomal translocations often result is in:
Disease
