Genetic Change and its Consequences

Question 1

What type of mutations can cause adult onset diseases such as cancer but cannot be transmitted to offspring

Answer 1

somatic mutations

Question 2

what type of mutations can be detected and heritable in the lineage of germ cells + can be transmitted to offspring

Answer 2

germline mutations

Question 3

What is a null mutation

Answer 3

completely lacks function

Question 4

what is a hypomorphic mutation

Answer 4

partial loss of gene function

Question 5

A DNA sequence variation that is common in the population is called a

Answer 5

polymorphism

Question 6

the cut off point between a mutation and a polymorphism is __%?

Answer 6

1&

Question 7

What is a glioblastoma

Answer 7

a highly aggressive brain tumour

Question 8

what does the karyotype for a glioblastoma show

Answer 8

multiple chromosome rearrangements

Question 9

intra chromosomal deletion can involve the loss of

Answer 9

many genes

Question 10

give two examples of syndromes arising from intra-chromosomal deletion

Answer 10

Wolf-Hirschhorn syndrome and cri du chat syndrome

Question 11

when the chromosomal segment is copied twice and retained as part of the chromosome, this is called

Answer 11

intra-chromosomal duplication

Question 12

give an example of a disease arising from intra-chromosomal duplication

Answer 12

charcot-marie-tooth disease

Question 13

when a chromosomal segment is inverted and reinserted into the chromosome, what is this called

Answer 13

chromosomal inversion

Question 14

what is the most common inversion in humans

Answer 14

in chromosome 9 p12q13

Question 15

what does Wolf-Hirschhorn syndrome result in

Answer 15

severe mental retardation

Question 16

cri du chat syndrome is a rare genetic disorder due to the deletion in chromosome 5, give two symptoms of this disease

Answer 16

mental retardation and characteristic mewing sounds

Question 17

what is chromosomal translocation

Answer 17

rearrangement of parts between non-homologous chromosomes

Question 18

give three examples of chromosomal translocation diseases

Answer 18

chronic myeloid leukaemia, burkitts lymphoma and acute promyelocytic leukemia

Question 19

chronic myeloid leukaemia results from a translocation between which chromosomes

Answer 19

chromosome 9 and chromosome 22

Question 20

a chromosome translocation in chronic myeloid leukaemia results in the formation of a chromosome called the

Answer 20

Philadelphia chromosome

Question 21

where is the ABL gene found

Answer 21

on chromosome 9

Question 22

where is the BCR gene found

Answer 22

on chromosome 22

Question 23

when the ABL gene and BCR gene come together, they fuse - what is activated

Answer 23

the ABL Oncogene

Question 24

what is an oncogene

Answer 24

a gene that has the ability to cause cancer

Question 25

where is the abl-bcr fusion gene located

Answer 25

on chromosome 22/ philadelphia chromosome

Question 26

what is nondisjunction

Answer 26

when chromosomes fail to separate during meiosis

Question 27

non disjunction can take place in meiosis 1 and

Answer 27

meiosis 2

Question 28

nondisjunction produces gametes with one missing chromosome or one

Answer 28

extra chromosome

Question 29

one extra chromosome produced by non disjunction is referred to as

Answer 29

trisomy

Question 30

one missing chromosome produced by nondisjunction is referred to as

Answer 30

monosomy

Question 31

trisomy 21 is when an individual has

Answer 31

three copies of chromosome 21

Question 32

if non disjunction occurs in meiosis 1 there is a ____ chance that there is trisomy or monosomy

Answer 32

50% chance trisomy, 50% monosomy

Question 33

if nondisjunction occurs in meiosis 2 there is a 50% chance the gametes are

Answer 33

normal

Question 34

most chromosomal mutations are

Answer 34

lethal

Question 35

give an example of a disease arising from a single base pair change

Answer 35

sickle cell disease

Question 36

in sickle cell disease which nucleotide change occurs within the beta hemoglobin gene

Answer 36

adenine to thymine

Question 37

give an example of a disease arising from the deletion of 3 base pairs

Answer 37

cystic fibrosis , deletion of CTT in the human CFTR gene

Question 38

a point mutation that changes a purine nucleotide to another purine or a pyramidine to another pyramidine is called a

Answer 38

transition mutation

Question 39

what are the pyramidines

Answer 39

cytosine and thymine

Question 40

what are the purines

Answer 40

adenine and guanine

Question 41

a substitution of a two ring purine for a one ring pyramidine or a pyramidine for a purine is referred to as a

Answer 41

transversion mutation

Question 42

are transitions or transversions more common

Answer 42

transitions are more common

Question 43

when a point mutation results in no change to the code it is called a

Answer 43

silent mutation

Question 44

when a point mutation results in a code that codes for a different amino acid it is called a

Answer 44

missense mutation

Question 45

when a point mutation changes an amino acid to a stop codon it is called a

Answer 45

nonsense mutation

Question 46

a frameshift mutation disrupts the

Answer 46

triplet code

Question 47

an insertion or deletion of a number of nucleotides in splice sites of an intron is called a

Answer 47

splice site mutation

Question 48

if there is a loss of the splicing site, it can result in the production of

Answer 48

aberrant proteins

Question 49

what is an indel mutation

Answer 49

insertion or deletion mutation - nucleotides added or removed

Question 50

a complete loss of function mutation is called an

Answer 50

amorphic mutation / null mutation

Question 51

with a loss of function mutation the protein structure is altered and no longer

Answer 51

works properly

Question 52

loss of function mutations are frequently

Answer 52

recessive

Question 53

a gain of function mutation results in a change to the gene product that means it gains a

Answer 53

new and abnormal function

Question 54

what is another name for a gain of function mutation

Answer 54

a neomorphic mutation

Question 55

gain of function mutations are frequently

Answer 55

dominant

Question 56

what are conditional mutations

Answer 56

mutations only expressed under certain conditions

Question 57

lethal mutations cause the

Answer 57

death of the organism

Question 58

supressor mutations

Answer 58

suppress the effect of another mutation

Question 59

an intragenic suppression mutation occurs in the

Answer 59

same gene as the original mutation

Question 60

an intergenic (extragenic) suppression mutation occurs

Answer 60

elsewhere in the genome - not on the same gene as the original mutation

Question 61

an organism with a suppressor mutation is referred to as a

Answer 61

double mutant

Question 62

supressor mutations have second mutations with alleviate the effects of the already existing mutation restoring the ____ phenotype

Answer 62

original

Question 63

loss of function mutations usually result in recessive phenotypes but there are two situations in which they can display dominance. they are

Answer 63

haploinsufficiency and the dominant-negative effect

Question 64

describe haploinsufficiency

Answer 64

single functional copy of gene present, functional copy doesn’t produce enough product, abnormal/diseased state in autosomal dominant disorders

Question 65

in haploinsufficiency is 50% of the residual gene function causes no effect it is

Answer 65

simple recessive

Question 66

in haploinsufficiency if loss of 50% of the gene function causes a disease it is

Answer 66

dominant

Question 67

haploinsufficiency is common in disorders where

Answer 67

gene dosage is crucial

Question 68

give two examples of phenotypes probably caused by haploinsufficiency

Answer 68

• alagille syndrome, multiple exostoses, tomaculous neuropathy, supravalvular aortic stenosis, trichorhinophalangeal syndrome

Question 69

what is another name for dominant negative mutations

Answer 69

antimorphic mutations

Question 70

dominant negative mutations produce an altered gene product

Answer 70

antagonistic to the wild type allele

Question 71

where are dominant negative mutations found

Answer 71

in cancer - p53, atm, ppargamma

Question 72

In marfan syndrome the defective glycoprotein product of the fibrillin gene anatgonises the product of the

Answer 72

normal allele

Question 73

marfan’s also could be as a result of

Answer 73

haploinsufficiency

Question 74

explain how marfans could be as a result of haploinsufficiency and not domiant negative

Answer 74

absence of one normal allele that causes the disease, not the presence of an abnormal allele

Question 75

what is marfans

Answer 75

an autosomal dominant disorder that affects connective tissue

Question 76

what is osteogenesis imperfecta

Answer 76

a group of genetic disorders that mainly affects the bones

Question 77

in osteogenesis mutations replace glycine with other amino acids, this would show

Answer 77

dominant negative effect

Question 78

the dominant negative effect in osteogenesis imperfecta would result in a severe/mild phenotype (circle one)

Answer 78

severe

Question 79

in osteogenesis imperfecta null mutations in either gene result in

Answer 79

haploinsufficiency

Question 80

null mutations in the genes in osteogenesis would result in a severe/mild phenotype (circle one)

Answer 80

mild