Chiasmata become visible during a leptotene b zygotene c pac

Chiasmata become visible during: a) leptotene b) zygotene c) pachytene d) diplotene e) diakinesis If a typical somatic cell has 24 chromosomes, how many chromosomes are expected in each gamete of that organism? A) 24 B) 12 C)6 D)48 E) none of the above In a healthy female, how many ova would be expected to form from 5 oogonia? How many first polar bodies? A) 20; 5 B) 10; 5 C) 20; 30 D) 10; 10 E) 5; 5 If two genes assort independently (they are not linked), then the double heterozygotes (Aa Bb) produce gametes a) with genotypic ratio of 1/2 AB: 1/2 ab b) with genotypic ratio of 1/4 AB: 1/4 Ab: 1/4 aB:1/4 ab c) with genotypic ratio of 1/4 A: 1/4 a: 1/4 B: 1/4 b d) that contain 2 alleles per each gene e) none of the above Round (R) seed shape is dominant to wrinkled (r) seed shape in pea plants. If a RR plant is crossed with a rr plant, what is the frequency of phenotypes in the F_1 generation? a) 1/4 RR, 1/2 Rr, 1/4 rr b) All wrinkled seeds c) 3/4 round seeds, 1/4 wrinkled seed d) An round seeds e) 9:3:3:1 ratio

Solution

12. chiasmata become visible during diplotene stage of prophase1 of meiosis, Answer (D)

13. if somatic cell have 24 chromosome, then gametes will have half of it i.e. 12 due to process of meosis during gametogenesis each gamete gets half number of chromosome, Answer (B)

14. 1 oogonia produce 2 oocytes, 1 oocyte produce 1 secondary oocyte( which will produce 1 egg and 1 second polar body) and 1 first polar body, then 5 oogonium will produce 10 eggs(ovum)[ 5x2=10] and 10 first polar body[ 1 oogonia gives 2 oocyte which produce 1 first polar body each thus 5 x 2= 10] thus Answer (D) 10,10

15 (C) 1/4 A: 1/4 a: 1/4 B: 1/4 b, when genes assort independently the genotypic ratip produced by doubl heterozygotes are in this ratio

16 rr X RR will produce phenotype Rr hence all will be of round phenotype in F1 generation and in F2 3round, 1 wrinkled will be produced. Answer(d) all are round seeds