In Class 12 Boards there will be Case studies and Passage Based Questions will be asked, So practice these types of questions. Study Rate is always there to help you. Free PDF Downloads of CBSE Class 12 Biology Chapter 5 Principles of Inheritance and Variation Case Study and Passage Based Questions with Answers were Prepared Based on the Latest Exam Pattern. Students can solve Class 12 Biology Case Study Questions Principles of Inheritance and Variation to know their preparation level.
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In CBSE Class 12 Biology Paper, There will be a few questions based on case studies and passage-based as well. In that, a paragraph will be given, and then the MCQ questions based on it will be asked.
Principles of Inheritance and Variation Case Study Questions With Answers
Here, we have provided case-based/passage-based questions for Class 12 Biology Chapter 5 Principles of Inheritance and Variation
Case Study/Passage-Based Questions
Case Study 1: During a study on the inheritance of two genes, the teacher asked students to perform an experiment. The students crossed white-eyed, yellow-bodied female Drosophila with a red-eyed, brown-bodied male Drosophila (i.e., wild). They observed that progenies in the F2 generation had 1.3 percent recombinants and 98.7 percent parental type combinations. The experimental cross with results is shown in the given figure.[Note: Dominant wild-type alleles are represented with a (+) sign in superscript.]
(i) By conducting the given experiment, the teacher can conclude that
A. Genes for eye color and body color are linked
B. Genes for eye color and body color show complete linkage
C. Linked genes remain together and are inherited
| (a) A and B only | (b) B only | (c) A and C only | (d) A, Band C |
Answer: (c) A and C only
(ii) Teacher asked to conduct an experiment on Drosophila because
| (a) the male and female flies are easily distinguishable | (b) it completes its life cycle in about two weeks |
| (c) a single mating could produce a large number of progeny flies | (d) all of these. |
Answer: (d) all of these.
(iii) Genes white-eyed and yellow-bodied located very close to one another on the same chromosome tend to be transmitted together and are called
| (a) allelomorphs | (b) identical genes | (c) linked genes | (d) recessive genes |
Answer: (c) linked genes
(iv) Select the correct statement regarding the given experiment.
| (a) The physical distance between two genes determines the strength of linkage |
| (b) The physical distance between two genes determines the frequency of crossing over |
| (c) The two linked genes always segregate independently of each other |
| (d) Both (a) and (b) |
Answer: (a) The physical distance between two genes determines the strength of linkage
(v) Assertion: When yellow-bodied, white-eyed Drosophila females were hybridized with brown-bodied, red-eyed males; and FI progeny was intercrossed, the F2 ratio deviated from 9: 3: 3: 1.
Reason: When two genes in a dihybrid are on the same chromosome, the proportion of parental gene combinations is much higher than in the non-parental type.
(a) Both assertion and reason are true and the reason is the correct explanation of assertion.
(b) Both assertion and reason are true but the reason is not the correct explanation of the assertion
(c) Assertion is true but the reason is false
(d) Both assertion and reason are false
Answer: (a) Both assertion and reason are true and the reason is the correct explanation of assertion.
Case Study 2: Turner’s syndrome is an example of mono somy. It is formed by the union of an allosome free egg and a normal ‘X’ containing sperm or a normal egg and an allosome free sperm. The individual has 2n = 45 chromosomes (44 + X0) instead of 46. Such individuals are sterile females who have rudimentary ovaries, under developed breasts, small uterus, short stature, webbed neck and abnormal intelligence. They may not menstruate or ovulate. This disorder can be treated by giving female sex hormone to the women from the age of puberty to make them develop breasts and have menstruation. This makes them feel more normal.
What is Turner’s syndrome an example of?
A) Trisomy
B) Monosomy
C) Polysomy
D) Karyotype alteration
Answer: B
How many chromosomes are typically present in an individual with Turner’s syndrome?
A) 44
B) 46
C) 45
D) 47
Answer: C
What is the chromosomal configuration in Turner’s syndrome?
A) 44 + XX
B) 44 + XY
C) 44 + X0
D) 44 + XXY
Answer: C
Which of the following is a characteristic of Turner’s syndrome?
A) Overdeveloped Breasts
B) Tall Stature
C) Normal Ovaries
D) Webbed Neck
Answer: D
What is the primary treatment approach for women with Turner’s syndrome from the age of puberty?
A) Giving Male Sex Hormone
B) Administering Insulin
C) Providing Female Sex Hormone
D) Performing Surgery
Answer: C
Individuals with Turner’s syndrome often experience which of the following reproductive issues?
A) Overactive Ovaries
B) Frequent Ovulation
C) Sterility and Rudimentary Ovaries
D) Multiple Pregnancies
Answer: C
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