test 1 genetic disease Flashcards
(235 cards)
1
Q
genes for specific proteins found..
A
in exactly one chromosome
2
Q
each person should have how many copies of one gene
A
two
3
Q
what is autosomal dominant
A
when a genetic disease is caused by having just one faulty copy of an autosomal disease
4
Q
ex of autosomal recessive
A
Marfan Syndrome
5
Q
Autosomal recessive
A
when a gnetic disease is caused by having two faulty copies of an autosomal disease
6
Q
ex of autosomal recessive
A
cystic fibrosis
7
Q
sex-linked genetic condition
A
when a disease is caused by mutations on a sex chromosome
8
Q
sex-linked genetic diseases almost always
A
affecting the X chromosom
9
Q
sex-linked genetic diseases can be
A
dominant or recessive
10
Q
one specific version (DNA sequence of a gene)
A
Allele
11
Q
The genes a person has
A
Genotype
12
Q
How a person looks
A
Phenotype
13
Q
Hetrozygote
A
has two different alleles
14
Q
hemizygous
A
one copy of a gene is missing
15
Q
how would hemizygous happen
A
one copy is deleted entirely or not produced, monosomy exists or person is XY
16
Q
punnet square for recessive disorder
A
25% chance the offspring will have it
17
Q
punnet square for dominant disorde
A
75% chance the offspring will have it
18
Q
how can mutations be defined
A
by how they affect DNA sequence
19
Q
what is a point mutation
A
one base pair is changed to something else
20
Q
what is a silent mutation
A
mutation causes the same amino acid to be produced
21
Q
missence mutation
A
mutation causes a new amino acid to be produced
22
Q
nonsense mutation
A
mutation creates a premature stop codon (UGA)
23
Q
what is frameshift mutation
A
one base paur is added or removed, causing all codons to be misread
24
Q
insertion frameshift mutation
A
base pair is added
25
deletion frameshift mutation
base pair is removed
26
how can mutations also be defined
by how they affect gene products
27
ways mutations affect gene products
- loss-of-function
- gain-of-function
- change-of-fucntion
28
types of loss-of-function mutations
amorphic
| hypomorphic
29
amorphic mutation
mutation that completely eliminates gene productivity
30
hypomorhic
mutation that slows gene product activity
31
types of gain-of-function mutations
hypermorphic
32
what is hypermorphic mutation
mutation speeds up gene product activity
33
types of change-of-function mutations
neomorphic
34
neomorphic mutation
causes gene product to do something else
35
what is PKU
Phenlketonuria
36
what is Phenlketonuria
disease characterized by a complete lack of functional copies of the enzyme phenylanine hydroxylase
37
what is phenylanine hydroxylase responsible for
responsible for converting the amino acid phenylalanine into the amino acid tyrosine
38
so what would a lack of functional phenylanine hydroxylase mean
BOTH copies of the gene suffered loss-of-function mutations
39
what is the gene for phenylalanine hydroxylase is called what
the PAH gene, found on 12th chromosome
40
how many loss of function mutations have been found in humans
15
41
first reason that Phenlketonuria is BAD
With no way for the body to remove excess phenylalanine, the phenylalanine will bind to and block receptors on the brain that allow other neutral amino acids, like valine and tyrosine, to enter the brain.
42
second reason why phenlketonuria is bad
With no way to produce tyrosine, the body is limited to its dietary supply from digested proteins
43
what is tyrosine important for
for the synthesis of imporant molecules like the neurotransmitter dopamine, and the pigment melanin
44
recessive disorders like PKU are always cause by
the complete lack of a protein in the body
45
depending on ___, recessive disorders__
on where the missing protein should be found and what it does, recessive disorders can be treated by artificially producing and injecting that protein
46
haploinsufficiency
a loss-of-function mutation impedes one copy of a chromosome
47
result of haploinsufficiency
one copy of a gene cannot produce enough protein to satisfy the needs of the cell/body , leading to a sick phenotype
48
what is Marfan Syndrome caused by
a loss-of-function mutation in the FBN1 gene, which codes for a protein called fibrillin-1
49
what is the job of fibrillin-1
to block a the protein TCF-B from binding to cells
50
what happens when there are not 2 copies of FBN1
there aren't enough copies of fibrilli-1 in the body to stop TGF-B from binding to cells
51
what is TGF-B
a complicated protein that does many things
52
some of the things TGF-B does
regulation of growth in the body, controlling how elastin fibers develop
53
how does TCF-B's regulation of growth in the body manifest
Marfan Syndrome makes people tal
54
how does TCF-B controlling how elastin fibers develop manifest
it especially effects the eye aorta and heart
55
what is dominant negative gene action
many enzymes in the body are actually multimers
56
what does it mean to be a multimers
made of two or more proteins combining to form a bigger protein
57
some loss-of function mutations cause
cause "bad" protein subunits that can still combine with other functional subunits that do not work, causing problems for the body
58
p53 is referenced as the
guardian of the genome
59
what is the main function of p53
directly binds to DNA and turns on some other genes`
60
the proteins produced by the genes turned on by p53 will either ....
stop the cell cycle if DNA damage is detected
| -cause the cell to enter apoptosis is DNA damage is not fixed quickly
61
what is apoptosis
programmed cell death
62
what is found in virtually all cancer cells
mutant or inactivated p53
63
cells must do what to become cancerous
inactivate or circumvent p53 `
64
how many subunits come together to build p53
4
65
what happens if any of the gene for any one of the subunits of p53 suffers a loss-of-function mutation
the broken piece will latch on to 3 working subunits and create a "broken" p53 protein
66
while ____ of p53s will be broken,, ______
half of p53s will be broken, half of the p53 tetramers in a cell will still work
67
with half of p53s broken
only one p53 will bind to DNA when there is a mutation
68
what happens if the wrong p53 binds to DNA
p53 won't properly turn on those genes and the cell will keep dividing and passing down mutant genes.
69
two ways to "get" a genetic disease
inherited mutations
| de novo mutations
70
inherited mutations
come when your parents or parent have a faulty copy of a chromosome that they pass to you
71
de novo mutations
happen independently
72
de novo mutations happen independently where
- a sperm or egg that fertilizes you
| - one cell very early in development mutates
73
if there is a De novo mutation in a sperm or egg
all of your cells will carry this mutation
74
if there is a De novo mutation in a cell of early development
mosaicism
75
mosaicism
only some of your cells carry the mutations
76
every offspring acquires how many de novo mutations
100
77
as a father ages...
he'll pass more de novo mutations to his offspring
78
Mendelian traits also called
monogenic traits
79
what are mendelian traits
traits affected by exactly one gene
80
patterns where the mutation can spread depend on
where the gene is located and how the protein functions
81
5 patterns in which mendelian traits can spread
```
autosomal dominant
autosomal recessive
x-linked dominant
x-linked recessive
y-linked
```
82
opposite of mendelian trait
polygenic trait, like height
83
what are pedigree charts
"family trees" that track a certain phenotype
84
Males n females on pedigree
males are squares, females circles
85
ppl with phenotype in question on pedigree
shaded
86
autosomal dominant
when a genetic disease is caused by having just one faulty copy of an autosomal gene
87
pedigree for autosomal dominant will reveal
- men n women affected equally
- affected person has affected parent, like mother or father
- if there is no affected person in a generation, transmission stops
- new (de novo) mutations sometimes possible
88
autosomal recessive
when a genetic disease is caused by having two faulty copies of an autosomal gene
89
autosomal recessive pedigree will reveal
- affected individuals often have unaffected marriage
- traits typically show up more in consanguineous marriages
- tends to skip generation
- if an affected child is born but neither parent has the disease, future children have a 25 chance of being affected
90
consanguineous
marriages between ppl w same ancestors
91
x-linked recessive
occur when all copies of the x chromosome carry the mutation
92
pedigree for x-linked recessive reveals
- disease more common in men
- sons of affected man will never inherit the trait from him
- daughters of an affected man are carriers
93
why are x-linked recessive disorders more common in men
men are hemizygous (only one copy of a gene)
94
x-linked dominant disorderss
occur when any copy of an X chromosome carries the mutation
95
pedigree for x-linked dominant disorders will reveal
trait is more common in females than males
- affected males pass trait to all daughters and no sons
- affected females have a 50% chance to pass disease to all children regardless of sex
96
why are x-linked dominant disorders more common in women
females has 2 chances instead of 1, male lethality
97
y-linked disorders come from
come from mutated genes on the y chromosome
98
the y chromosome is so small that
the genes are unimportant, except for determining "maleness"
99
are there disease that follow y-linked patterns
no, almost all mutations are de novo, not inherited
100
why are there no diseases that follow y-linked patterns
almost all y mutations result in male sterility... cannot propagate
101
the average person carries how many fatal mutations
1 or two, but they are fine because they only carry one copy
102
with over 20,000 genes, what is very unlikely
its extremely unlikely that the fatal mutation a person carrier will be on the same gene that their parter's fatal mutation is on
103
what happens in inbreeding
the chance of two people having the same very rare de novo mutation INCREASES a lot
104
what are the alterations to normal mendelian patterns
- common recessive traits
- male lethality
- variable penetrance
105
are many recessive traits are very rare in a population
yes
106
what happens if a trait is recessive but very common in a population
it will appear to be transmitted in a dominant fashion
107
examples of common recessive traits
straight hairline, blood type O
108
(male lethality)for many X-linked dominant diseases, affected males often result in what
in miscarriage
109
for many X-linked dominant diseases, affected males often result in miscarriages. why?????
because they have NO functioning copies to do damage control
110
Male lethality causes females
to disproportionately have X-linked dominant diseases, and always pass these to daughters and never sons (they will die)
111
examples of Male Lethality affecting x-linked dominant disorders
Rett syndrome, incontinentia pigmenti
112
in variable penetrance, a person with a dominant mutant genotype..
does not always express a sick phenotype
113
if 100% of people with a "sick genetype are sick ,70%
penetrence is 100%, 70%
114
variable penetrence makes some dominantdisordes
appear to skip a generation
115
ex of variable penetrance
BRCA1 mutation
116
BRCA1 mutation
leads people to increased risk of breast cancer. 80 % of women w mutation will develop breast cancer
117
chimera
When two different zygotes (twins) grow in the same womb and “fuse” in some way
118
Chimera results in
one fetus that has two unique sets of DNA.\
119
does chimera happen in humans
no aside from test tubes
120
mosaicism
When a developing embryo suffers a mutation early in development
121
in mosaicism the mutation
propagates to all descendants of that early cell, creating a human with two distinct genotyppes
122
mosaicism is...
VERY COMMON
123
how much of DNA has instructions for making proteins
1%
124
part of DNA w instruction for proteins
genes
125
how many genes in the body
20 thousand
126
how many unique proteins can be made
80-100 thousand
127
all 20,000 genes are found on what
chromosomes
128
what is a chromosome
a tightly wound chunk of DNA
129
almost every human has how many chromosomes
46
130
23 chromosomes are inherited from where
mother's egg
131
the other 23 chromosomes come from where
the father's sperm
132
what is the n number of chromosomes for humans
23
133
are the numbers 23 and 46 the same for all organisms
no
134
n t
the number of chromosomes inherited from one parent
135
in most animal species the organisms have how many n
2n `
136
karyotype
the map of all chromosomes sorted by size
137
how are chromosomes numbered
#1-22, X or Y
138
what are chromosomes 1-22 called
autosomes
139
the x and y chromosomes are called what
allosomes
140
biggest autosomes
#1
141
smallest autosomes
#22
142
male
XY
143
female
XX
144
aneuploidy
when an organism does not have 2n chromosomes
145
a triplet of one chromosome
trisomy
146
only one copy of one chromosome
monosomy
147
zero copies of one chromosome
Nulisomy
148
four copies of one chromosome
Tetrasomy
149
Multiple copies of all chromosomes
polyploidy
150
examples for polyploidy
3n,4n,10n etc
151
Robertsonian Translocation
look at assignment 1
152
does the body need to have a certain number of each protein inside
yes
153
what happens when one extra copy of a chromosome exists (trisomy)
the genes on the chromosome are transcribed and translated 1.5 times faster than they should be (because they have 3 chances instead of 2 )
154
what happens w too much protein
processes can go awry
155
what will happen with monosomy
proteins are only made at 50% of the rate they should be
156
are most aneuploidies survivable
NO
157
what will happen to all nullisomies in early development
miscarry
158
are monosomies UNsurvivable
yes, w two exceptions
159
exceptions to surviving monosomies
turner syndrome, cri du chat syndrome
160
what is considered the only true monosomy that is survivable
turner syndrome
161
what happens in turner syndrome
there is one X chromosome, and no Y chromosome
162
result of turner syndrome
short stature, typically infertility, webbed neck, normal intelligence
163
another name for cri du chat syndrome
5p minus syndrome
5th chromosome minus 1 p arm
164
is cri du chat syndrome a true monosomy
no
165
what i smissing in cri du chat syndrome
a portion of the p arm of the 5th chromosome
166
result of cri du chat syndrome
delayed development, mental retardation, heart defects, cat-like cry
167
exceptions to trisomies
patau syndrome
edwards syndrome
down syndrome
168
patau syndrome is a
trisomy 13
169
result of patau syndrome
live birth achievable, death within 6 months
170
edwards syndrome is a
trisomy 18
171
result of edwards syndrome
live birth achievable, death within 6 months
172
down syndrome is a
trisomy 21
173
result of down syndrome
mental impairment, flattened nose and slanted eyes, heart defects
174
which chromosomes are least sensitive to abnormalities
sex chromosomes
175
examples of abnormalities from XX/XY that are seen in humans
```
XXX
XXY
XYY
XXXX
XXXY
XXXXY
```
176
XXX
Triple X syndrome
177
XXY
Klinefelter syndrome
178
XYY
Jacob's syndrome
179
the XX/XY abnormalities are usually
the XX/XY abnormalities are usually
180
what does DNA stand for
deoxyribonucleic acid
181
what is the dna
genetic material and instructions for making proteins
182
what is the central dogma of biology
transcription and translation
183
what is transcription
dna can be used to make rna
184
what is translation
rna can be used to make proteins
185
how does dna unwind
with dna helicase
186
what happens when DNA unwinds
RNA polymerase attaches to one side and makes a complementary strand of mRNA
187
what is mRNA
messanger RNA
188
is the entire strand of DNA turned into mRNA
NO
189
what is transcribed in transcription
small regions (genes)
190
genes account for how much of chromosomal DNA
1 to 2 percent
191
where is DNA found in eukaryotes
in the nucleus
192
where are ribosomes found
in rough ER r cytosol
193
what does mRNA do after being made in the nucleus
exit to cytoplasm to find ribosome to be translated
194
translation is which process
where ribosomes turn mRNA into proteins
195
when are codons turned into amino acids
translation
196
average lifespan of mRNA before it degrades
3 to 8 minutes
197
DNA expected lifespan
521 years
198
4 nitrogenous bases of DNA
Adenine
Guanine
Thymine
Cytosine
199
the order of bases in DNA determine what
the protein will be formed
200
how many base pairs are in the genome
3 billion
201
what is a codon
each 3 letter chunk in the genetic code
202
each codon codes for what
a specific amino acid
203
the order of codons determines what
the order of amino acids
204
sometimes on a chart
T turns into U
205
what are amino acids
20 similar-looking molecules with an N side and C side
206
what is an R chain
what makes each amino acid unique
207
what is a protein
longstrings of amino acids
208
median length of proteins in humans
350
209
mean length of protein in humans
476
210
how do proteins make their shape
fold according to predictable patterns
211
how do proteins attach
C side of the previous amino acid combines with the N side of the next amino acid
212
the chemical bond between the C side and N side of amino acids
holds them together, called peptide bonds
213
another name for proteins
polypeptides
214
amino acid R chains can be
polar or nonpolar
215
water is
POLAR
216
water and amino acids
polar amino acids attracted, nonpolar repelled
217
nonpolar other name
hydrophobic
218
polar other name
hydrophyllic
219
______ attract each other and form ___
cysteine residues attract each other and form disulfide bridges
220
amino acid R chains can also be
postively or negatively charged
221
positive amino acids
are basic and attract negative (acidic) amino acids
222
some cases where mutation will have no change on a protein
when the codon is different but codes for the same amino acid.. so it is the same protein
223
case where a mutation has a small change on a protein
the codon is different and codes for a different amino acid, but it is still polar/nonpolar (like the original)
224
case where a mutation has a large change on a protein
the codon is different, codes for different amino acid, the charge (polar/nonpolar) is different
225
types of chromosomal mutations
translocation, inversion, deletion, duplication
226
translocation
When genetic information of one chromosome becomes attached to another chromosome
227
inversion
A portion of a chromosome is inverted
228
deletion (chromosomal)
A portion of a chromosome is deleted
229
duplication
Some genes are duplicated because a segment from one chromosome attaches to its homogenous chromosome
230
B-thalassemia protein and gene
B globin, B gene
231
B-globin is used in
hemoglobin
232
β0-thalassemia
the mutation causes the β gene to be completely inactivated, leading to no β globin being produced
233
B+-thalassemia
sometimes the amount of b-globin produced is decreased, but not completely gone
234
what is an acrocentric chromosome
chromosome with the centromere located near the end of the chromosome, making one arm dramatically long than the other.
235
the acrocentric chromosmes
13,14,15,21, and 22
