Biology NEET - XII: Chapter 5- Principles of Inheritance and Variations Part 1
Gregor Mendel conducted his famous experiments on pea plants between 1856 and 1863, spanning 7 years. During this time, he studied the inheritance of traits across generations, laying the foundation for modern genetics through his formulation of the laws of inheritance.
When did Mendel conduct his experiment on peas?
1856 to 1863 ( 7 years)
Key Terms
When did Mendel conduct his experiment on peas?
1856 to 1863 ( 7 years)
How many true breeding pea plant varieties did Mendel select?
14
What are the units of inheritance?
Genes
What does the I gene in ABO blood groups control?
The kind of sugar on the surface of RBC
Morgan crossed yellow bodied, white eyed male fruit flies with brown bodied, red eyed female fruit flies to get F1 generation. True/false?
False.
Morgan crossed yellow bodied, white eyed female fruit flies with brown bodied, red eyed male fruit flies to get F1 generation.
What percent of the offspring obtained in F2 generation were recombinants when yellow bodied, white eyed female fruit flies with brown bodied, red eyed male fruit flies were crossed?
1.3%
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| Term | Definition |
|---|---|
When did Mendel conduct his experiment on peas? | 1856 to 1863 ( 7 years) |
How many true breeding pea plant varieties did Mendel select? | 14 |
What are the units of inheritance? | Genes |
What does the I gene in ABO blood groups control? | The kind of sugar on the surface of RBC |
Morgan crossed yellow bodied, white eyed male fruit flies with brown bodied, red eyed female fruit flies to get F1 generation. True/false? | False. Morgan crossed yellow bodied, white eyed female fruit flies with brown bodied, red eyed male fruit flies to get F1 generation. |
What percent of the offspring obtained in F2 generation were recombinants when yellow bodied, white eyed female fruit flies with brown bodied, red eyed male fruit flies were crossed? | 1.3% |
What percent of the offsprings obtained in F2 generation were recombinants when white and miniature wings were taken as characters in fruit flies? | 37.2% |
Phenylketonuria is caused by the mutation of which gene? | It is caused by mutation in gene that codes for enzyme phenyl alanine hydroxylase. |
Who discovered X chromosome? | Henking |
How many chromosomes does a female honeybee have? | 32 |
What type of disorder is cystic fibrosis-Mendelian disorder or chromosomal disorder? | Mendelian disorder |
Is myotonic dystrophy dominant or recessive? Is it sex linked? | Autosomal dominant |
In colour blindness, defect is caused in | red or green cones of the eye |
Why is sickle cell anaemia caused? | Substitution of glutamic acid by valine at the six position of the bets globulin chain of haemoglobin |
Is phenylketonuria sex linked? | No |
What happens due to the absence of phenyl alanine hydroxylase in phenyl ketonuria patient? | Phenylalanine is not converted into tyrosine, so phenylalanine is accumulated and converted to phenylpyruvic acid. |
What causes thalassemia? | Mutation or deletion in gene which causes reduced rate of formation of α or β globin chains of haemoglobin. |
α- Thalassemia is controlled by which genes? | Two closely linked genes HBA1 and HBA2 on chromosome 16 of each parent |
α- Thalassemia can occur only because of mutation in one gene. True/false? | α- Thalassemia can occur because of mutation or deletion in one or more of the four genes (the genes being two closely linked genes HBA1 and HBA2 on chromosome 16 of each parent). |
β- Thalassemia is controlled by which genes? | Single gene HBB on chromosome 11 of each parent |
Down’s syndrome is caused due to | Trisomy of chromosome 21 |
Who coined the term genetics? | Bateson |
What is the chemical basis of heredity? | DNA |
What is the physical basis of heredity? | Gene |
Who is called the father of modern genetics? | Bateson |
Who is called the father of experimental genetics? | Morgan |
In the experiment conducted by August Weisman, the tails of mice were cut for how many generations? | 21 generations |
The gene for flower colour in pea is located on which chromosome? | 1 |
The gene for seed colour in pea is located on which chromosome? | 1 |
The gene for plant height in pea is located on which chromosome? | 4 |
The gene for flower position in pea is located on which chromosome? | 4 |
The gene for pod shape in pea is located on which chromosome? | 4 |
The gene for pod colour in pea is located on which chromosome? | 5 |
The gene for seed shape in pea is located on which chromosome? | 7 |
Which law would have Mendel discovered he had known that the 7 chosen characters in pea were present on 4 chromosomes? | Linkage |
Who formulated Mendel's generalisations into laws of inheritance? | Carl Correns |
How many postulates were given by Mendel? | 4 |
What is hemizygous condition? | Haploid condition |
If there are n heterozygous allelic pair, then what will be the number of gametes? | 2^n |
Which of the Mendel's laws has no exceptions? | Law of segregation |
1:2:1:2:4:2:1:2:1 is the ratio of which property of a dihybrid cross? | Genotypic ratio |
Mendel's first law is | Law of segregation |
Mendel's second law is | Law of independent assortment |
What is the phenotypic ratio of a trihybrid cross? | 27:9:9:9:3:3:3:1 |
What is the cross in which sexes of parents are reversed as compared to other cross called? | Reciprocal cross |
What is the cross in which a hybrid is crossed with its parent called? | Back cross |
Crossing a hybrid with its dominant parent is called | Out cross |
What is the relation between genotypic and phenotypic ratios in a test cross? | Genotypic and phenotypic ratios are the same |
Who discovered incomplete dominance? | Carl Correns |
What deviation from Mendelian crosses is observed in the flower colour in Mirabilis jalapa? | Incomplete dominance |
What deviation from Mendelian crosses is observed in the plumage colour of Andulasian fowl? | Incomplete dominance |
What deviation from Mendelian crosses is observed in the coat colour of short horned cattle? | Co-dominance |
What is the phenotypic and genotypic ratio in coat colour of short horned cattle? | 1:2:1 in both (polygenic inheritance) |
What is the relation between genotypic and phenotypic ratios in codominance? | Genotypic and phenotypic ratios are the same |
What is lethality as observed in coat colour of german mice? | Homozygous dominant mice (golden coat colour)die |
What is the relation between genotypic and phenotypic ratios in lethality? | Genotypic and phenotypic ratios are the same |
Which medication is provided to mother to prevent erythroblastalis foetalis? | Rhogam |
When is the first dose of rhogam provided to mother? | 6th month |
When is the second dose of rhogam (first booster) provided to mother? | 7th month |
When is the third dose of rhogam (second booster) provided to mother? | 8th month |
When is the fourth dose of rhogam (third booster) provided to mother? | 72 hours after pregnancy |
What is qualitative inheritance? | Monogenic inheritance- single dominant allel determines complete character |
What is quantitative inheritance? | Polygenic inheritance |
What deviation from Mendelian crosses do height and intelligence show in humans? | Polygenic inheritance |
What deviation from Mendelian crosses does flower colour in sweet pea show? | Complimentary genes |
What is the phenotypic ratio in F2 generation under the effect of complementary genes in sweet pea? | 9:7 (purple is C and P allele are present in genotype or else white) |
What is the phenotypic ratio in F2 generation under the effect of supplementary genes? | 9:3:4 |
What is the phenomenon of masking the expression of a gene by another non-allelic gene called? | Epistasis |
What is the gene which suppresses the other gene in epistasis called? | Epistatic gene |
What is the gene which is suppressed by the other gene in epistasis called? | Hypostatic gene |
What is dominant epistasis? | Dominant gene at one locus suppresses dominant gene at other locus. |
What is recessive epitstasis? | Recessive gene suppresses the dominant gene at other locus |
Fruit colour in summer squash is the example of which type of deviation from mendelian laws? What is its phenotypic ratio? | Dominant epistasis | 12:3:1 |
Coat colour in mice can be the example of which type of epistasis? What is its phenotypic ratio? | Recessive epistasis | 9:3:4 |
Secondary constriction 1 is found in which chromosomes? | Chromosome number 1, 13, 14, 21, 22, Y |
Secondary constriction 2 is found in which chromosomes? | Chromosome number 1, 10, 13, 16 and Y |
Allosomes are also known as | Sex chromosomes |
Idiochromosomes are also known as | Sex chromosomes |
What is the representation of chromosomes of a cell arranged in decreasing order of size called? | Idiogram |
What does honey contain? | Nectar + secretions of sub-maxillary glands of honey bee |
What is value of X/A in meta female fruit flies? | 1 |
What is value of X/A in female fruit flies? | 1 |
What is value of X/A in intersex fruit flies? | 1/2 < X/A <1 |
What is value of X/A in male fruit flies? | 1/2 |
What is value of X/A in meta male fruit flies? | <1/2 |
Who gave the term mutation? | Hugo deVries |
What kind of genetic mutation is albinism? | Autosomal recessive |
What kind of genetic mutation is tay-sachs disease? | Autosomal recessive |
What kind of genetic mutation is Alkaptonuria? | Autosomal recessive |
What kind of genetic mutation is polydactyly? | Autosomal dominant |
What kind of genetic mutation is brachydactyly? | Autosomal dominant |
What kind of genetic mutation is Huntington's chorea? | Autosomal dominant |
What kind of genetic mutation is responsible for being able to tast PCT? | Autosomal dominant |
Is congenital night blindness autosomal or sex linked? | Sex linked |
What is meant by chromosomal abberration? | Change in number or arrangement of genes of chromosome |
What is the ploidy of wheat? | 6n |
What is hypoploidy? | The number of chromosomes decreases in an organism |
What is the chromosomal number in nullisomy? | 2n-2 |
What is the difference between double monosomy and nullisomy? | Nullisomy- two chromosomes of same type are deleted | Double monosomy- two chromosomes of different types are deleted (2n-a-b) |
What is mixed aneuploidy? | 2n-a+b (one chromosome deleted, one chromosome added) |