Transcript Answer

1
The rules of the contest
•There are 6 groups,3 groups from
each sections and each group
includes 3 students ;
•There are single choose
questions, ，rushing to answer
question(true or false and fill in
the blank)， short /long answer
questions and audient answer
question.
•Short and long answer questions
will scored by the judges .
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The first round
single choose questions
The rules of the round
There are 5 choices(A,B,C,D,E),among
them only one answer is correct. each
students must be answer one question
from each group, if correct 50marks will
be added,if wrong discount any marks。
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4
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Choose below please
Table
tennis
banana
coke
math
lemon
tomato
physics
Badminton
Water
melon
Mahmud
tea
biology
Baseball
apple
juice
surgeon
Football
orange
milk
physician
Cricket
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• 1 Coding part of eukaryotic gene is
below:
•A. exon
B. intron C. promotor
•D. enhancer E. poly A
Answer：A
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2 Match the pedigree with the most likely mode
of inheritance.
A. AD
B. .AR
C. XD
D. XR
E. Y
Answer:B
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3 Which of the following is not a numerical
chromosomal abnormality?
A.polyploidy
B. robertsonian ranslocation
C. triploidy
D. trisomy
E. aneuploidy
Answer：B
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•4· A woman with an X-linked dominant
disorder（heterozygote） mates with a
phenotypically normal male. On average,
what proportion of this couple's daughters
will be affected with the disorder?
•A. 0.1
B. 0.5
C. 1
•D. 0.25
E. 0
Answer：B
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• 5·
Which of the following individuals has the
highest risk of having a child with Down
syndrome?
A.a female with a t (13q; 14q)
B. a male with a t (13q; 14q)
C. a female who is 35 years old
D. a male who is 45 years old
E. a female with a t (14q; 21q)
Answer：E
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6 Which statement about Down
syndrome is false?
A. The frequency increases dramatically
in mothers over the age of 40
B. The cause is a non-disjunction when
chromosomes do not separate during the
first meiotic division
C. Affected individuals have an extra
autosome
D. The long time lag between onset of
meiosis in ovarian tissue (during fetal
development) and its completion (at
ovulation) is most likely the reason for
increased incidence in older mothers
E. None, all statements are true
Answer：E
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• 7 A human male carrying an allele for a trait on the
X chromosome is:
•A. heterozygous
B. homozygous
•C. hemizygous
• D. monozygous
E. holozygous
Answer：C
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Answer：B
• 8 Two normal
individuals who both have
achondroplasia (autosomal
dominant disorder) mate.
What is the occurrence
risk for this disorder in
their offspring?
•A. 25%
B. 50%
C. 75%
D.100%
E. 0%
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9.Why would you predict that half of the human babies
born will be males and half will be females?
A. Because of the segregation of the X and Y
chromosomes during male meiosis
B. Because of the segregation of the X chromosomes
during female meiosis
C. Because all eggs contain an X chromosome
D. Because, on average, one-half of all eggs produce
females
E. Because of the formation of the Barr body early during
embryonic development
Answer：A
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• 10 Inheritance base of polygenic
inheritance pattern are multigenes which
are
•A. codominance, no additive affects
•B. codominance, additive affects
•C. incomplete dominance, no additive
affects
• D. incomplete dominance, additive
affects
• E. delayed dominance, additive affects
Answer：B
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11. Klinefelter's syndrome (XXY) is an
example of chromosomal aneuploidy that
can be readily diagnosed by:
A.Behavioral analysis
B.Somatic cell genetics
C.Karyotyping
D.Biochemical analysis
E.Pedigree analysis
Answer：C
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12Which is NOT a common method used in
human genetic analysis?
A.pedigree analysis
B. karyotyping
C. RFLP analysis
D. test cross
E. somatic cell genetics
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Answer：D
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13. Albinism carrier married with albinism patient
what is the most likelihood of the albinism among the
offspring?
A. 9/26
B. 1/2
C. 1 /4
D. 3/8
E. 3/4
Answer：B
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14. A gene that determines color perception is on the X
chromosome of humans. The dominant allele confers
color vision; the recessive leads to color blindness. A
heterozygous woman, with normal color vision, marries
a man with normal color vision. What is the probability
that their son will be color blind?
A. 0
B. 1\4
C. 1\3 D. 1\2
E. 2\3
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Answer：D
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15. A Barr body (X chromatin) is:
A. the cause of Down's syndrome
B. an amplified gene
C. a polytene chromosome
D. a ribonucleoprotein particle
E. an inactivated X chromosome
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• Answer：E
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16.A man with a Mendelian
syndrome marries a normal
woman. Of their 9 children, all
4 boys are normal, whereas all
5 daughters are affected by the
same syndrome. What is the
most likely inheritance pattern
for this syndrome?
A.autosomal dominant
B.autosomal dominant with
female preponderance
C. X-linked dominant
D. Y-linked
E. autosomal recessive 返回
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Answer：C
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17. A Down syndrome patient is a
A.Euploid
B. Triploid
C. Hypodiploid
D. Hyperdiploid
E. Monosomy
.
D
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18. Which of the following cell types would have
the greatest number of chromosomes?
A. a human egg cell
B. a human sperm cell
C. a human zygote
D. a human gamete
E. all have the same number of chromosomes
C
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The Second Round
The rules of contest：
Each group must be answer one
question，group members can discuss
in I minute，one of the contestant
answer question，each
question100marked.
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1
4
6
5
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1 Describe the pedigree
characteristics of AD.
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Answer：
1. Each affected individual has one
affected parent.
2. 50% of sibs are affected.
3. Males and females are affected
with equal probability.
4. Passed in vertical fashion.
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2 Blood type A male (heterozygote) mate with
blood type AB female, what are the
probabilities of the blood types of their child?
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Answer:
A bloodtype: 50%
B bloodtype: 25%
AB bloodtype: 25%
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3 The diagram below is a pedigree of a
common trait.
(1).Give the most likely pattern of inheritance
and carefully explain your reasoning.
(2). Write the genotype of Ⅰ2, Ⅱ2, Ⅲ4, Ⅳ4. Use
"A" to indicate a dominant gene and "a" to
indicate a recessive gene.
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Answer:
(1) Autosomal recessive. Reasons:
(a)Generation Ⅱ and generation Ⅲ have not any
affected individual. These indicates that the
pedigree inherit by recessive mode.
(b)The number of affected male and affected
females is equal approximately. And, we did not
find the phenomenon of criss-cross inheritance.
(2). Ⅰ2: aa Ⅱ2:Aa Ⅲ4:Aa Ⅳ4:aa
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4
What is single gene
disorder? Please write the
main types of it.
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Answer:
Single gene disorder: the disorders
that are due to single mutant genes
(major gene) with a large effect on
the patient's health and inherited in
Mendelian fashion
Main types:
Autosomal dominant diseases (AD)
Autosomal recessive diseases (AR)
X-linked dominant diseases (XD)
X-linked recessive diseases (XR)
Y-linked diseases
Mitochondrial disorder
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5Please describe the approaches of
genetic diseases.
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Answer:
1. History of disease, Symptoms and body Signs
2. Pedigree analysis
3. Cytogenetics checking
4. Biochemical checking
5. DNA molecular diagnosis or Gene diagnosis
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6Describe the standard classification of
chromosome (Denver Classification).
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Answer:
46
Describe the mechanism and
pathogenesis of sickle cell anemia
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Answer:
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Fill in the blank
1 A genetic trait which is
measurable characteristics
called
.
quantitative trait
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True or false
•2.Familiar diseases are same
with genetic diseases.
F
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True or False
3.If sons inherit fathers phenotype
is called Y-linked inheritance.
T
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•True or False
•4.If the threshold of the persons
is high, the less probability of the
person have affected in
polygenetic diseases.
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True or False
Individuals who carry a balanced chromosome
rearrangement cannot have normal children.
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Fill in the blank
6.Ⅱ2 in the genetic pedigrees
stand for (
)
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second person of second generation
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Fill in the blank
The reasons of euploid are
diandry , digny ---------- and
endoduplication..
endomitosis
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Fill in the blank
8, Types of deletion are -------and
INTERSTITIAL .
Terminal
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Fill in the blank
9. The reasons of aneuploid are
chromosome loss and --------.
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chromosome dysjunction
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Fill in the blank
.
10.Phenylketonuria
is caused by an
absence or deficiency of
.
phenylalanine hydroxylase
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Fill in the blank
11.Albinism
is caused by an
.
absence or deficiency of-----------------..
Tyrosinase
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• 12.( ) is the kind of chromosome in
which centromere near one end, with
arms of very different lengths
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submetacentric chromosome
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•Audients answer questions
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True or False
1 Recurrence risk increases with
the number of affected in a family
in polygenic disease.
T
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•2 A female with blood group A and
a male with blood group B have a
son whose blood group is O. The
chance that their next child will have
blood group O is
•A.1\2 B.1\4 C.1\3
•D.3\4 E.2\3
B
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•3 ‘B’ represents the gene for a dominant trait and ‘b’
its recessive allele. If Bb mates with bb:
•A. All offspring will be of the recessive phenotype.
•B. All offspring will be of the dominant phenotype.
•C. 50% of the offspring will be of the recessive
phenotype.
•D. 25% of the offspring will be of the dominant
phenotype.
•E. 75% of the offspring will be of the dominant
phenotype.
C
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4.Which of the following would Not help to
distinguish autosomal dominant from
autosomal recessive inheritance?
A. presence of consanguinity
B. sex ratio of affected individuals
C.appearance of the disease phenotype in
multiple generations of the family
D. proportion of affected offspring in each
mating
E. all of the above
B
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Chromosome abnormalities
account for 50 percent of
miscarriages.
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NTD diagnosis technology including
A.amnionic AFP
B. acetylcholinesterase
C. target ultrasonography
D.A+B+C
E. not all of them
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All of the below are the normal
chromosomal structure Except
below
A.centromere B. telomere
C. fragile site
D. satellite E. primary constriction
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Encountered one of the following circumstances,
which should Not be recommended for
chromosome checks:
A.Family chromosome abnormality has been found
in the individual or congenital malformations.
B. Multiple abortions of women and her husband.
C.Pregnant women under the age of 35.
D. Primary amenorrhea and the men and women
who Infertility. E. There are internal and external
genital malformations, gender
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The rules of the game：
Each participating team optional choose
different valued one question and after
discussions for one minute in team, choose
one participant to answer the question.
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Choose me！
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3
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1. What are the
differences between the
qualitative trait and
quantitative trait?
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1ANSWER:
Qualitative trait: genetic traits which are present
or absent. One has the trait or not. The
distribution in a population is discontinuous.
Quantitative trait: genetic traits which are
measurable characteristics. The distribution in a
population is continuous.
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2. Please write the
pedigree characteristics
of X-linked dominant
inheritance.
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2Ans:
(1) the ratio of affected females to the males
is approximately 2 to 1.
(2) each affected individual has one affected
parent.
(3) all daughters of affected males are
affected, all sons of affected males are
normal; 50% offspring of affected female have
chance of being affected.
(4) padded in a vertical fashion.
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3.Please write the different
types of autosomal dominant
inheritance.
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3 Ans:
(1) complete dominance
(2) incomplete dominance or
semidominance
(3) codominance
(4) irregular dominance
(5)delayed dominance
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4. Please write the pedigree
characteristics of autosomal
recessive inheritance.
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4 Ans:
(1)Both parents are carriers.
(2)25% of sibs are affected. Males and
females are affected with equal probability.
(3)2/3 of unaffected sibs are carriers.
(4)The diseases are sporadic.
(5)The risk of offspring is higher in
consanguineous marriage.
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5Describe the levels of diagnosis
of genetic diseases
？
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Symptomatic diagnosis
Presymptomatic diagnosis
Prenatal diagnosis.
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6 Describe chromosomal
nondisjunction
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Nondisjunction occurs when the normal separation of
the chromosome pairs during mitosis or meiosis is
disrupted.
If nondisjunction occurs in mitosis, it would be couse
mosaics; If nondisjunction occurs in first phase of
meiosis , all the gametes will be abnormal. If
nondisjunction occurs in second phase of meiosis ,
50% gametes will be abnormal.
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•The chromosome analysis
is indicated in many clinical
conditions for proper
diagnosis of genetic
diseases:
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Congenital malformations
Mental retardation
Repeated abortion
Sex determination
Prenatal diagnosis
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2
3
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1 Describe the inheritance
characteristics of polygenic disease.
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1ANSWER:
1. First degree relatives have the high risk of affected.
Risk of affected relatives’ falls off very quickly with the
degree of relationship.
2. Consanguinity also increases the probability of an
affected child for a multifactorial trait. But only slightly
when compared to rare AR diseases.
3. Recurrence risk increases with the number of affected
in a family
4. Recurrence risk increases with severity of the defect
5. Carter-effect: If the sex distribution of a trait is not
uniform, relatives of an affected individual of the less
frequently manifesting sex are more likely to have
problems
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2 A woman with blood type A has a child
with blood type O. She claims that a friend
of hers is the child’s father.(a) His blood
type is B. Can he be excluded as the child’s
father on this evidence alone? Give
reasons.(b) Does the additional information
that both his parents actually are blood type
AB permit him to be excluded? Why or why
not?
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2Answer
(a) No, he can not be excluded as the child’s father.
Reason: the woman is blood group B and she has a
child with blood group O, we can conclude that this
woman is heterzygote. If the man is also heterzygote
with blood group B, then they will have the chance
to produce a child with blood group O.
(b) Yes, he can be exclude as the child’s father.
Reason: his parent are all blood group AB, so, he
have not chance to inherited a recessive gene (i).
Then, he have not chance to have a child with blood
group O.
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The father of a certain family belongs to blood
group AB, and the mother to blood group O.
They have four children, one belonging to AB,
one to A, one B and one O. One of these children
is adopted and another is a child from an earlier
marriage of the mother.
State which is the adopted child and which is the
child from an earlier marriage and why? .
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3 Ans:
The child belonging to blood group AB is adopted.
Blood group O is the child from an earlier
marriage. Because parents are blood group AB
and O respectively, they will have child with blood
group A or B. Mother belong to blood group O,
she have not any chance to have a child with blood
group AB, but she have the opportunity having a
child with blood group O.
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4
What are the different names, clinical
features and karyotypes of Down’s
syndrome?
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Different names: Down syndrome or trisomy 21
syndrome
Clinical futures:
Growth retardation
Varying degrees of mental retardation
Flattened face
Upward slanting of the eyes with epicanthal folds
Simian crease
open the mouth
diminished muscle tone
congenital heart disease
big toe wildly spaced
big tongue
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•
•
•
•
•
•
•
•
Karyotypes:
Trisomy ——47, XX(XY), ＋21
Mosaic ——46 , XX(XY)/47 , XX(XY), ＋21
Unbalance translocation
Karyotype of affected：
46, XX(XY), －14, ＋t(14q21q)
Karyotype of balance carrier：
45, XX(XY), －14, －21, ＋t (14q21q)
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5
Describe the mechanism, clinical
futures, and treatment of PKU.
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Mechanism :is caused by an absence or
deficiency of phenylalanine hydroxylase.
The result is a 20-fold increase in the levels of
pheylalanine in the blood.
Clinical futures: Untreated leads to mental
Retardation, Associated complications: behavior
disorders, cataracts, skin disorders, and
movement disorders
Treatment: phenylalaine restricted diet
(specialized formulas available)
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6.What are the Sickle cell anemia
(describe pathogenesis,
mechanism, treatment)
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• Treatment
• Blood transfusion is used to
– Control severe anemia
– Reduce the risk of complications of sickle hemoglobinopathies
(cerebrovascular accident, hypersplenism, etc.)
– Excess iron can cause the appearance of sideroblastic
conditions
– Transfusion interferes with the typical laboratory findings for the
disorder.
• Alternative treatment:
– Activation of fetal hemoglobin genes
– Bone marrow transplantation
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7 What is the difference between a
chromosome abnormality and a genetic
disorder?
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• A chromosome abnormality is caused
by the presence of extra or missing chromosome
material. The genes in a person with a
chromosome abnormality are normal.
• It is the number of genes (increased or
decreased) that is abnormal.
• A genetic disorder is caused by a change in a
single gene, or genetic message, coding for a
particular protein.
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