Home
Class 12
BIOLOGY
The possibility of a female becoming hae...

The possibility of a female becoming haemophilic is extremely rare because mother of such a female has to be at least `overset("(i)") "____"` and father should be `overset("(ii)") "____"`

A

(i) haemophilic, (ii) carrier

B

(i) carrier, (ii) haemophilic

C

(i) haemophilic, (ii) normal

D

(i) haemophilic, (ii) haemophilic

Text Solution

Verified by Experts

The correct Answer is:
B
Haemophilia is genetically due to the presence of a recessive sex linked gene h, carried by X-chromosome. A female becomes haemophilic only when both its X-chromosomes carry the gene `(X^(h)X^(h))` However. Such females generally die before birth because the combination of these two recessive alleles is lethal. A female having only one allele for normal blood clotting present on the other X-chromosome is dominant. Such females are known as carriers. In case of males, a single gene for the defect is able to express it self as the Y-chromosome is devoid of any corresponding allele (X^(h)Y)`. The possibility of human female becoming haemophilic is extremely rare because she has to be homozygous recessive for the trait, i.e., her father must be haemophilic and mother must be atleast a carrier.
Promotional Banner

Similar Questions

Explore conceptually related problems

Given below are three statements (A-C) each with one or two blanks. Select the option which correctly fills up the blanks in any two statements A. Diseases or infections which are transmitted through sexual intercourse are collectively called overset("i")"____" deseases B. Gential herpes is overset("ii") "____" disease C. Sterilisation in males is overset("iii")"____" while in females is overset("iv") "____"

In honeybees, females are overset("(i)")"____" having overset("(ii)")"____" chromosomes and males are overset("(iii)")"____" having overset("(iv)")"____" chromosomes

Fill in blanks (w.r.t. experimental material used by Morgan) (i) Females are easily distinguishable from the male by the "_____" body size. (ii) It has many type of hereditaly variations that can be seen with "____" power microscope. (iii) Male individuals have hetromorphic "________" .

From the statements given below, choose the option that are true for a typical female gametophyte of a flowering plant. (i) It is 8-nucleate and 7-celled at maturity. (ii) It is free-nuclear during the development. (iii) It is situated inside the integument but outside the nucellus. (iv) It has an egg apparatus situated at the chalazal end.

Which of the following statements are correct regarding surgical methods of contraception ? (i) These are generally advised to the male/female partner as a terminal method to prevent any more pregnancies (ii) Surgical procedure in male is called tubectomy and that in the female, vasectomy (iii) Reversibility is easily possible (iv) They block gamete transport and thereby prevent conception.

Column I, Column II The number of five-digit numbers having the product of digit 20 is, p. > 70 A closest has five pairs of shoes. The number of ways in which four shoes can be drawn from it such that there will be no complete pair is, q. <60 Three ladies have each brought their one child for admission to a school. The principal wants to interview the six persons one by one subject to the condition that no mother is interviewed before her child. The number of ways in which interview can be arranged is, r. in (50 ,110) The figures 4, 5, 6, 7, 8 are written in every possible order. The number of numbers greater than 56000 is, s. in (40 ,70)

Answer the following questions . a. The earth's magnetic field varies from point is space. Does it also change with time ? It so , on what time scate does it change appreciably ? b. The earth's core is known to contain iron. Yet geologists do not regard this as a source of the earth's magnetism why ? c. The charged currents in the outer conducting regions of the earth's core are thought to be responsible for earth's magnetism . What might be the ' battery ' (i.e., the source of energy) to sustain these currents ? d. The earth may have even reversed the direction of its field several times during its history of 4 to 5 billion years. How can geologists know about the earth's field in such distant past ? e. The earth's field departs from its dipole substantially at large distances (greater than about 30,000 km) what agencies may be responsible for this distortion ? f. Interstellar space has an extremely weak magnetic field of the order of 10^(-12) T, Can such a weak field be of any significant consequence ? Explain. [Note : Exercise 2 is meant mainly to arouse your curiosity . Answers to some question above are tentative or unknown . Brief answers wherever possible are given at the end . For details , you should consult a good text on geomagnetism.]