DNA Repair and How do mutations occur

Question 1

Loss or alterations (mutations) of accessary proteins often leads to _____.

Answer 1

cancer

Question 2

_____ are involved in the nomenclature of mutations that tells where it takes palce

Answer 2

coordinates

Question 3

Changes in the nucleotide sequence of a chromosome that caused disease. DNA deletion, insertion, substitution, silent, missense mutations

Answer 3

Gene mutation that is responsible for disorders

Question 4

Unnatural bases are recognized and removed by a specific _______

Answer 4

DNA glycosylase

Question 5

A ___ mutation results in no change where the mutation produces the same amino acid

Answer 5

silent

Question 6

Deamination involves DNA _____ (chemical modification)

Answer 6

substitution

Question 7

Way that a mutation deamination and depurination, most frequent spontaneous chemical reactions.

Answer 7

hydrolytic attack

Question 8

Genes at differ loci are transmitted independently

Answer 8

Principle of Independent Assortment

Question 9

A ____ mutation does not occur in gametes and in not heritable

Answer 9

somatic mutation

Question 10

_______ guides homologous recombination

Answer 10

DNA base pairing

Question 11

Rearrangements/Translocations, Deletions, Insertions, Duplications are _____ disorders

Answer 11

Chromosome Disorders

Question 12

DNA breaks also arise from _____ that become stalled or broken

Answer 12

DNA replication forks

Question 13

_______ facilitate transcription regulation

Answer 13

nuclear receptors

Question 14

______ enhance transcription can be further away

Answer 14

Enhancer

Question 15

About _____ of inherited human disorders are single base mutations

Answer 15

1/3

Question 16

DNA sequence variants of a gene.

Answer 16

Alleles

Question 17

A ___ results in an altered protein

Answer 17

frameshift

Question 18

Sexually reproducing organisms possess genes that occur in pairs and that only one member of this pair is transmitted to the offspring

Answer 18

Principle of segregation

Question 19

Multiple genes, gene-environment are _____ disorders

Answer 19

Multifactorial or Complex

Question 20

DNA of each human cell loses about_____ bases (adenine/guanine) everyday due to their deoxyribose hydrolyzation of N-glycosyl linkages, a spontaneous reaction called depurination

Answer 20

5000 purine

Question 21

____ mutations include radiation and chemicals

Answer 21

Induced mutations

Question 22

DNA breaks often occur from _____ or ______

Answer 22

radiation damage; reactive chemicals

Question 23

each member of a chromosome pair carries the same allele, then the individual is called ______ for that gene

Answer 23

homozygous

Question 24

______ can be repaired by Non-homologous end joining without a template which creates a mutation at the site where the DNA duplexes are joined; Inadvertent joining of two segments from different chromosomes that results in chromosomal translocations, which often give rise to disease; Homologous recombination repairs DNA double strand breaks accurately without loss or alteration of the DNA sequence

Answer 24

Double strand DNA breaks

Question 25

Holiday junctions are commonly found in what process?

Answer 25

Homologous recombination

Question 26

Of the thousands of random changes created every day in the DNA of a human cell by heat, metabolic accidents, radiation of various sorts, and exposure to substances in the environment,______ accumulate as mutations in the DNA sequence

Answer 26

only a few

Question 27

Way that a mutation occurs by the methyl group donor S-adenosyl-methionine

Answer 27

Uncontrolled methylation

Question 28

DNA repair pathway that is how thymine dimers are repaired; large portion of DNA excisied

Answer 28

nucleotide excision repair

Question 29

Cells carefully regulate the use of _____ in DNA repair

Answer 29

homologous recombination

Question 30

each member of a chromosome pair carries a different allele, then the individual is called ______ for that gene

Answer 30

heterozygous

Question 31

Genetic exchange between a pair of homologous DNA sequences

Answer 31

Homologous recombination

Question 32

Spontaneous reaction involving the deoxyribose hydrolyzation of N-glycosyl linkages

Answer 32

depurination

Question 33

The importance of DNA repair is also demonstrated by the ______ that follows the inactivation of a DNA repair gene.

Answer 33

increased rate of mutation

Question 34

____ and _____ hydrolytic reactions, are the two most frequent spontaneous chemical reactions known to create serious DNA damage in cells.

Answer 34

Deamination and depurination

Question 35

cytosine to uracil in DNA is estimated to occur at a rate of 100 bases per genome per day.

Answer 35

Deamination

Question 36

we now know that fewer than one in _____ accidental base changes in DNA results in a permanent mutation; the rest are eliminated with remarkable efficiency by DNA repair.

Answer 36

1000

Question 37

Depurination involves DNA ____ (chemical modification)

Answer 37

deletion

Question 38

Disorders that deal with the X and Y chromosome or mitochondrial genome

Answer 38

Sex Linked and Mitochondrial

Question 39

Is DNA stable or unstable?

Answer 39

Stable

Question 40

____ mutations arise naturally during DNA replication (mitosis) or during meiosis

Answer 40

spontaneous mutations

Question 41

Special type of cell division that occurs in sexual reproduction. It involves two successive nuclear divisions with only one round of DNA replication, thereby, producing haploid cells from a diploid cell.

Answer 41

Meiosis

Question 42

A ___ results in extra or missing amino acids

Answer 42

deletion or insertion

Question 43

DNA repair pathway where a single base changes

Answer 43

base excision repair

Question 44

Dominant, Recessive,Codominant are _____ disorders

Answer 44

Single Gene Disorders

Question 45

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. From Greek mitos, a thread, referring to the threadlike appearance of the condensed chromosomes.

Answer 45

Mitosis

Question 46

Process where Unnatural bases are recognized and removed by a specific DNA glycosylase

Answer 46

base excision repair

Question 47

Nomenclature of mutations involve what elements?

Answer 47

amino acid, genomic/mRNA/protein, coordinates, and substitutions

Question 48

T/F: A number of accessory proteins are involved in control of DNA repair

Answer 48

True

Question 49

A ____ mutation is inherited

Answer 49

germline

Question 50

_______ is a mechanism to: Accurately repair double strand DNA breaks; Exchange bits of genetic information; Assures accurate chromosome segregation during meiosis

Answer 50

Homologous recombination

Question 51

Maintaining the genetic stability that an organism needs for its survival requires _______ and ______ the many accidental lesions that occur continually in DNA

Answer 51

an extremely accurate mechanism for replicating DNA and mechanisms for repairing

Question 52

A ___ mutation results in a stop codon being produced and the protein is truncated

Answer 52

Nonsense

Question 53

A spontaneous _______ in DNA occurs at a rate of about 100 bases per cell per day

Answer 53

deamination of cytosine to uracil

Question 54

an encounter with reactive metabolites produced in the cell (including reactive forms of oxygen, H2O2, -OH, and -O2); exposure to chemicals in the environment; ultraviolet radiation from sun can produce a covalent linkage between two adjacent pyrimidine bases in DNA to form thymine dimers (presented later in this lecture) cause _____

Answer 54

DNA damage

Question 55

T/F: Loss of essential proteins needed for repair generally cause cancer

Answer 55

False; they are lethal

Question 56

The enzymes catalyzing repair are present at high concentrations in the _____

Answer 56

nucleus

Question 57

What are the 2 major DNA repair pathways?

Answer 57

base excision repair and nucleotide excision repair

Question 58

These premutagenic lesions (dimers) alter the structure of DNA and consequently inhibit polymerases and _______

Answer 58

arrest replication

Question 59

_____ mutations mobile genetic elements that jump around to DNA; can result in protein w altered amino acid sequence or issues with regulation

Answer 59

Transposons

Question 60

phenotype of a ______ gene will be observed only in the homozygous state

Answer 60

recessive

Question 61

A ___ mutation results in a base pairing mutation where 2 purines bind or 2 pyrimidines bind

Answer 61

Transition

Question 62

A ___ mutation results in a single amino acid change

Answer 62

Missense

Question 63

Two DNA strands switch partners between two double helices

Answer 63

Holliday junction (cross-strand exchange)

Question 64

covalent linkage of two adjacent pyrimidines by UV light from the sun

Answer 64

Pyrimidine (C or T) dimer formation

Question 65

Genetic exchange that takes place between a pair of homologous DNA sequences

Answer 65

Homologous recombination

Question 66

Most such spontaneous changes in DNA are temporary because they are immediately corrected by a set of process that are collectively called _______

Answer 66

DNA repair

Question 67

______ are sequence variants of a gene. You inherit one _____ of each autosomal gene from your mother and one from your father.

Answer 67

Alleles

Question 68

An identifiable segment of DNA sequence with a known physical location on a chromosome and enough variation between individuals. Its inheritance and co-inheritance with alleles of a given gene can be traced. Markers can help link an inherited disease with the responsible genes. DNA segments close to each other on a chromosome tend to be inherited together. Markers are used to track the inheritance of a nearby gene that has not yet been identified but whose approximate location is known. The marker itself may be a part of a gene or may have no known function; used in linkage analysis

Answer 68

Genetic Markers

Question 69

The importance of DNA repair is evident from the large investment that cells make in ______

Answer 69

DNA enzymes

Question 70

Variation between individuals in a population at specific nucleotides in their DNA sequence.

Answer 70

Single nucleotide polymorphisms (SNPs)

Question 71

Dimers may be repaired by _____ or _______ but unrepaired dimers are mutagenic

Answer 71

photoreactivation or nucleotide excision repair

Question 72

lose 5000 purine bases (A or G) per day in each cell due to thermal disruption of their N-glycosyl linkages to deoxyribose.

Answer 72

Depurination

Question 73

A ___ mutation results in a base pairing mutation of the incorrect pyr/pur

Answer 73

Transversion

Question 74

_______ are single base differences at a specific position in the genome; occurring within a gene (can) give rise to an allele. There are hundreds of thousands (millions) in the genome

Answer 74

Single nucleotide polymorphisms (SNPs)

Question 75

phenotype of a ____ gene will be observed in the homozygous or heterozygous state

Answer 75

dominant

Question 76

Way that a mutation occurs by reactive oxygen species

Answer 76

oxidative damage