In human child, sex is determined by
Size and number of sperms in semen
Size of egg to be fertilized
Sex chromosomes of father
4. Sex chromosomes of mother
Round seed trait (R) is dominant over wrinkled (r) seed trait in Pea. Heterozygous round seeded plant (Rr) is crossed with wrinkled seed plant (rr). What is the possible progeny?
302 round : 102 wrinkled
210 round : 95 wrinkled
103 round : 99 wrinkled
103 round : 315 wrinkled
A dihybrid cross produces the following progeny - AaBb = 240; Aabb =754; aaBb = 746; aabb = 260. What is the distance between the two genes on the chromosome?
12.5 map units
1 map unit
20 map units
25 map units
Male pattern baldness is a trait
sex-linked
sex-limited
sex-influenced
Y-linked
A colour blind girl is rare because she will be born only when
Her mother and maternal grand father were colour blind
Her father and maternal grand father were colour blind
Her mother is colour blind and father has normal vision
Parents have normal vision but grand parents were colour blind.
Identify the incorrect statement regarding experiments on Pisum sativum by Gregor Mendel?
He conducted hybridisation experiments on garden peas for seven years (1856-1863) and proposed the laws of inheritance in living organisms.
It was for the first time that statical analysis and mathematical logic were applied to problems in biology.
Unfortunately his experiments had a small sampling size, which gave less credibility to the data that he collected.
He investigated characters in the garden pea plant that were manifested as two opposing traits.
Which of the following is a recessive trait for a character choosen by Mendel in garden pea?
Violet flower color
Yellow pod color
Axial flower position
Tall stem height
Indentify the incorrect statement:
Tall plant produce gametes by meiosis and the dwarf plants by mitosis.
Only one allele is transmitted to a gamete.
The segregation of alleles is a random process.
Gametes will always be pure for the trait.
The ultimate source of allelic variation is:
Recombination
Natural selection
Mutation
Drift
In the case of co-dominance, the F1 generation resembles:
Dominant parent
Recessive parent
Both the parents
None of the parents
What can be the possible blood groups of progeny whose father and mother are of A and B group respectively?
A and B only
AB only
All except O
A, B, AB and O
When Morgan hybridised yellow-bodied, white-eyed females to brown-bodied, red-eyed males and intercrossed their F1 progeny, the F2 ratio deviated very significantly from the 9:3:3:1 ratio. this can be attributed to the fact that:
The genes are located on X and Y chromosomes
Fruit fly has abnormal chromosomes
The genes are located on the X chromosome
The genes exhibit incomplete dominance
What is incorrect for Hemophilia?
In this disease, a single protein that is a part of the cascade of proteins involved in the clotting of blood is affected.
In an affected indlvidual a simple cut will result in non-stop bleeding.
The heterozygous female (carrier) for haemophilia may transmit the disease to sons.
The possibility of a female becoming a haemophilic is extremely rare because mother of such a female has to be hemophilic and the father should be a carrier.
Sickle cell anaemia results from.
A chromosomal aberration
Non disjunction of autosome
A point mutation
Blood transfusion reaction
What is the mode of inheritance of phenylketonuria?
Autosomal recessive
Autosomal dominant
Sex linked recessive
Sex linked dominant
Failure of cytokinesis after telophase stage of cell divislon results in an increase in a whole set of chromosomes in an organism and, this phenomenon is known as:
Aneuploidy
Translocation
Polyploidy.
Inversion
Which of the following is not a feature of Down's Syndrome?
It is caused by a non-disjunction in an autosome
The affected individual has trisomy of chromosome 21
The aflected individual has a characteristic simian palmar crease
The mental development of affected individual is normal
Identify the incorrect statement:
In addition to recombination, mutation is another phenomeonon that leads to variation in DNA.
Chromosomal aberrations are commonly observed in cancer cells.
A classical example of a point mutation is sickle cell anaemia.
Non ionising radiations cannot be mutations.
Pedigree analysis is resorted to for genetic analysis in humans rather than conventional genetic methods because:
I. Choice matings are not possible
II. Number of progeny is limited
Of the two statements:
Only I is correct
Only II is correct
Both I and II are correct
Both I and II are incorrect
Match each item in Column I with one item in Column II and chose your answer from the codes given below:
Column I
Disorder
Column II
Feature
I. Phenylketonuria
II. Sickle Cell anemia
III. Down's Syndrome
IV. Turner's Syndrome
(i) Rudimentary ovaries
(ii) Gynecomastia
(iii) Trisomy 21
(iv) Lack of enzyme PAH
(v) Lack of tyrosinase
(vi) Mutation GAG to GUG
(vii) Mutation GUG to GAG
I - v; II - vii; III - iii; IV - i
I - iv; II - vi; III - iii; IV - i
I - v; II - vi; III - iii; IV - ii
I - v; II - vi; III - iii; IV - i
In a monohybrid cross F1 progeny resemble neither of the parents. What would be true in this case?
The parental traits would not appear in any of the F2 -progenies
The F2 phenotypic ratio will be different from the F2 genotypic ratio
It could be a case of incomplete dominance
The F2 phenotypic ratio will be similar to any Mendelian monohybrid cross
The two alleles of a gene pair are located on:
Homologous sites on homologous chromosomes
Heterologous sites on homologous chromosomes
Homologous sites on heterologous chromosomes
Heterologous sites on heretologous chromosomes
Male heterogamety is not seen in:
Humans
Melandrium album
Birds
Fruit fly
Aneuploidy results from :
Point mutations
Gross structural changes in chromosomes
Failure of cytokinesis after telophase stage of cell division
Failure of segregation of chromatids during cell division
Which of the following are correct regarding linked genes?
I. are located near each other on the same chromosome.
II. violate the law of independent assortment
III. segregate together during meiosis
Only I and II
Only I and III
Only II and III
I, II, III
Consider the cross AaBb x AaBb. If the alleles for both genes exhibit complete dominance, what genotypic ratio is expected in the resulting offspring?
1:1:1:1
9:3:3:1
3:6:3:1:2:1
1:2:1:2:4:2:1:2:1
Two phenotypically normal individuals have an affected child. What can we conclude about the parents?
they both carried the diesease allele
they are not the parents of the child
they are affected
no conclusions can be drawn
What is the basis of pleiotropy?
A spontaneous mutation during the replication of DNA.
Interrelationship between various metabolic pathways in the body.
Chromosomal aberration as chromosomes are the vehicles of genes.
the behaviour of chromosomes during meiosis or gamete formation.
A female whose father was colorblind marries and normal male whose father was also colorblind. What is the probablility that their daughter will be colorblind?
0 %
25 %
50 %
75 %
In humans, the dominance relationship between the A and B alleles of ABO blood group gene is an example of
complete dominance.
incomplete dominance.
codominance.
epistasis
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