QQuestion
With the help of a checkerboard show the phenotypic ratio of offspring produced in F2 generation as a result of a cross between a pure black coloured and rough-haired guinea pig and a pure white and smooth-haired guinea pig. “Father plays the main role in the determination of sex of the offspring” – justify the statement with the help of a checkerboard. [3+2=5]
OR
Write three reasons behind Mendel’s success. Establish a relationship between phenotype and genotype with the help of proper examples. [3+2=5]
✓Answer
Pure Black and Rough: BBRR
Pure White and smooth: bbrr
F1 generation: BbRr (Hybrid Black and Rough)
Phenotypic ratio = 9 : 3 : 3 : 1
The father contributes an X chromosome to all of his offspring, while the mother contributes either an X or a Y chromosome. This means that the father’s X chromosome will always be present in his offspring, while the mother’s X chromosome may or may not be present.
Therefore, the father has a greater influence on the sex of the offspring than the mother.
Or
Three reasons behind Mendel’s success:
- Mendel used purebred pea plants which had consistent traits, allowing him to clearly observe inheritance patterns.
- He conducted large-scale hybridization experiments, which provided statistically significant data.
- Mendel applied mathematical and statistical methods to analyze the inheritance patterns, making his conclusions reliable.
Relationship between phenotype and genotype:
Phenotype is the observable physical appearance of an organism, while genotype is the genetic makeup that determines the phenotype. For example, a pea plant with the genotype “YY” will have yellow seeds, indicating that yellow color is the phenotype, whereas the presence of “Y” and “y” alleles (genotype Yy) results in the same yellow phenotype due to dominance. Conversely, “yy” results in green seeds, showing how genotype influences phenotype.
Related Questions
More WBBSE Moderate level questions
Match the words in column-A with the most appropriate words in column B and re-write the correct pair mentioning the serial no. of both columns COLUMN - A COLUMN - B 1. Meninges (a) Decrease in the number of digits in the legs 2. Sexual reproduction (b) Submergence of islands 3. Roller tongue (c) Centromere 4. Evolution of the horse (d) Telomere 5. Environmental problem of Sundarban (e) Protects brain and spinal cord from mechanical injury 6. Attaches chromosome with spindle fibre (f) Controlled by autosome (g) Occurs through the production of gametes and their union
An inherent trait of organisms is the prodigality of reproduction; as a result, the number of organisms increases in a geometric proportion - justify the validity of the statement with two proper examples.
Write two reasons behind the selection of pea plants by Mendel for his experiments on heredity.
In spite of being pure in respect of one trait, what else could an organism be in respect of another trait?
Which would be the genotypic and phenotypic ratio in the F2 generation of a hybrid cross in case of incomplete dominance? (a) 2 : 1 : 1 (b) 1 : 1 : 1 (c) 1 : 2 : 1 (d) 1 : 2 : 2
Which two of the following genotypes represent the genotype of a pea plant with yellow coloured and wrinkled seed? (a) YYr, Yy (b) YYRr, YRR (c) yRR, yyRr (d) YYRR, yyrr
Match the words in Column A with the most appropriate words in Column B and rewrite the correct pair mentioning the serial no. of both columns (any five): [1×5=5] Column A Column B 2.13 Adrenaline (a) Air Pollutant 2.14 Self pollination (b)According to Haldane the hot marine water containing different organic compounds 2.15 The position of flower is axial (c)The adoloscent phase of human development 2.16 Hot Dilute Soup (d)No need of agent 2.17 SPM (e)The senescence phase of human development. 2.18 Britleness of bone and pain at bone joints (f) Increases heart beat, cardiac output and blood pressure. (g) Dominant trait
Predict what would be the hereditary results in the following cases: One of the parents is thalassaemic and the other is a carrier of the thalassaemic gene. Both of the parents are carriers of the thalassaemic gene What are the symptoms of Thalassaemia? OR Tabulate three pairs of opposite traits regarding the seed of the pea plant as selected by Mendel. Show the process of sex determination in men with the help of a checkerboard.
Match the words in column-A with the most appropriate words in column B and re-write the correct pair mentioning the serial no. of both columns Column-A Column-B 1. Diabetes insipidus (a) Law of Independent Assortment 2. Schwann cell (b) Brittleness of bone 3. Meiosis (c) Exists between neurolemma and myelin sheath of axon 4. Senescence phase (d) Hyposecretion of ADH 5. Genetic disease (e) Spore mother cell and germ mother cell 6. The second law of Mendel (f) Colour blindness
What is the role of genetic counselling in the eradication of geneticdisease from the society? Black-smooth hair is produced in F₂ generation resulting from a cross between pure black-rough haired guinea pig (BBRR) and pure white-smooth haired guinea pig (bbrr). Show their possible genotypes and genotypic ratios with the help of a table. [3 + 2]
Mention the dominant and recessive traits of two characters related with seed and one character related with flower of pea plant. Very often it is experienced that a colour-blind son is born to apparently normal parents. Show with the help of a cross how it happens.
In which of the following crosses, will the F1 generation seed's tall and dwarf traits appear in a 1:1 ratio? (a) Tt x Tt (b) TT x Tt (c) TT x tt (d) Tt x tt