12th Grade > Biology
PRINCIPLES OF INHERITANCE AND VARIATION MCQs
Total Questions : 45
| Page 3 of 5 pages
Answer: Option C. -> Factors
:
C
Gene is aunit which takes part in inheritance and expression of hereditary characters. Mendel called it 'element' or 'factor'.
:
C
Gene is aunit which takes part in inheritance and expression of hereditary characters. Mendel called it 'element' or 'factor'.
Answer: Option C. -> 300
:
C
This is a typical dihybrid cross. Both parents are homozygous, so two different types of gametes will be formed- (TV) and (tv) respectively. The F1 plant will be heterozygous with the genotype (TtVv). Four different gametes are formed by the F1 plants- (TV), (Tv), (tV), (tv).
As you can see from the Punnett tool, the phenotypes in the F2 progeny are observedin a 9:3:3:1 ratio. Among these, tall plants with white flowers are one (TTvv) and two(Ttvv), thus a total of 3- recombinants which are produced3 times in every 16progenies. Hence out of 1600 plants, 316∗1600=300 are tall plants with white flowers.
:
C
This is a typical dihybrid cross. Both parents are homozygous, so two different types of gametes will be formed- (TV) and (tv) respectively. The F1 plant will be heterozygous with the genotype (TtVv). Four different gametes are formed by the F1 plants- (TV), (Tv), (tV), (tv).
As you can see from the Punnett tool, the phenotypes in the F2 progeny are observedin a 9:3:3:1 ratio. Among these, tall plants with white flowers are one (TTvv) and two(Ttvv), thus a total of 3- recombinants which are produced3 times in every 16progenies. Hence out of 1600 plants, 316∗1600=300 are tall plants with white flowers.
Answer: Option A. -> 47
:
A
Klinefelter's syndrome is caused due to the presence of an additional X chromosome, resulting in a chromosome composition 44 autosomes + XXY (totally, 47 chromosomes). Such an individual exhibits an overall masculine development. However, such individuals could develop breasts upto an extent. The male secondary sexual characters would also be poorly developed, and the individuals would generally be sterile.
:
A
Klinefelter's syndrome is caused due to the presence of an additional X chromosome, resulting in a chromosome composition 44 autosomes + XXY (totally, 47 chromosomes). Such an individual exhibits an overall masculine development. However, such individuals could develop breasts upto an extent. The male secondary sexual characters would also be poorly developed, and the individuals would generally be sterile.
Answer: Option B. -> In birds, males have the same type of sex chromosome, while females have a distinctive pair.
:
B
Sex determination based on the chromosomes need not always be the same as we see in humans, where males have XY chromosome and females have XX chromosome. In fruit flies, males have only one X chromosome, while females have two X chromosomes. However, birds have a completely different set of chromosomes. The males possess ZZ sex chromosome and the females have ZW chromosome, which is a stark contrast to what we see in humans.
:
B
Sex determination based on the chromosomes need not always be the same as we see in humans, where males have XY chromosome and females have XX chromosome. In fruit flies, males have only one X chromosome, while females have two X chromosomes. However, birds have a completely different set of chromosomes. The males possess ZZ sex chromosome and the females have ZW chromosome, which is a stark contrast to what we see in humans.
Answer: Option B. -> A - 3, B - 1, C - 4, D - 2
:
B
Mendel selected seven pairs of contrasting characters in pea plants for his experiments. They were stem height, flower position and colour, seed shape and colour, and pod shape and colour. Stem height was considered to be either tall or dwarf, flower position was either axial or terminal, pod shape either inflated or constricted and seed shape either round or wrinkled.
:
B
Mendel selected seven pairs of contrasting characters in pea plants for his experiments. They were stem height, flower position and colour, seed shape and colour, and pod shape and colour. Stem height was considered to be either tall or dwarf, flower position was either axial or terminal, pod shape either inflated or constricted and seed shape either round or wrinkled.
Answer: Option A. -> Eye color
:
A
The gene that controls eye coloris present on the X chromosome in Drosophila. Hence, it expresses differently in males and females. Sinceit is present on the X chromosome, thistrait is said to be sex-linked.
:
A
The gene that controls eye coloris present on the X chromosome in Drosophila. Hence, it expresses differently in males and females. Sinceit is present on the X chromosome, thistrait is said to be sex-linked.
Answer: Option B. -> the physical expression of a trait
:
B
Phenotype refers to the observable characteristics of an organism. Hair colour andeye colourare all phenotypic characters of organisms. The genetic makeup of an organism is called genotype.
:
B
Phenotype refers to the observable characteristics of an organism. Hair colour andeye colourare all phenotypic characters of organisms. The genetic makeup of an organism is called genotype.
Question 28. Which among the following statements is/are correct with respect to the law of dominance?
A. Each character is controlled by pair of discrete units called factors.
B. In a dissimilar pair of factors one is dominant and the other is recessive.
C. It explains the expression of one trait in F1 and both traits in F2 generation.
D. Explains the proportion of phenotypes, 3:1 obtained in F2 generation.
A. Each character is controlled by pair of discrete units called factors.
B. In a dissimilar pair of factors one is dominant and the other is recessive.
C. It explains the expression of one trait in F1 and both traits in F2 generation.
D. Explains the proportion of phenotypes, 3:1 obtained in F2 generation.
Answer: Option D. -> A, B, C & D
:
D
Law of dominance explains that out of the two factors determining a character, one is dominant- this is the one that gets expressed inheterozygous condition. Thus the dominant character appears in F1 generation when the progenies are heterozygous. The law of dominance also explains the reappearance of the recessive factor in theF2 generation, when the recessive factors re-unite in a homozygous condition. Thus, it also explains the proportion of 3:1 obtainedin the F2 generation.
:
D
Law of dominance explains that out of the two factors determining a character, one is dominant- this is the one that gets expressed inheterozygous condition. Thus the dominant character appears in F1 generation when the progenies are heterozygous. The law of dominance also explains the reappearance of the recessive factor in theF2 generation, when the recessive factors re-unite in a homozygous condition. Thus, it also explains the proportion of 3:1 obtainedin the F2 generation.
Answer: Option B. -> Test cross
:
B
The cross between a suspected heterozygote with the recessive parent is called test cross. This cross basically helps to confirm if the organism in question is homozygous or heterozygous for the dominant allele.
An intercross is an organism that is the offspring of genetically dissimilar parents or stock; especially offspring produced by breeding plants or animals of different varieties, breeds, or species.
Top cross is a cross between a superior or purebred male and inferior female stock to improve the average quality of the progeny.
:
B
The cross between a suspected heterozygote with the recessive parent is called test cross. This cross basically helps to confirm if the organism in question is homozygous or heterozygous for the dominant allele.
An intercross is an organism that is the offspring of genetically dissimilar parents or stock; especially offspring produced by breeding plants or animals of different varieties, breeds, or species.
Top cross is a cross between a superior or purebred male and inferior female stock to improve the average quality of the progeny.
Latest Videos
Latest Test Papers
Login With Google
Old way of Login
Login With Email