of a single x hm USE 1-50 Grede Form for this section proponed that dosage compe
ID: 270446 • Letter: O
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of a single x hm USE 1-50 Grede Form for this section proponed that dosage compensation in placental mammals occurs via who proposed the theory of chromosomal mondisjunction, was a student of Hunt Morgan, Calvin Bridges Thomas Hunt Morgan Walter Suttion Reginald Punnett Thomas mant Morgan Calvin Bridges: Walter Suton Dridges: Thomas Munt Morgan in which haplo d- L The system for ses determination for bees, wasps, and ants is referred to as generabe gametes via itosis A)O, females B) haplodiploidy; females C, xxxo, males Di haplodiploidy, males E) none of the above 4. The "Tather ef fruit ly genetics" is A) Calvin Bridges Walter Sutton Reginald Punnett Gregor Mendel homas Hunt Morgan 5?The SRY gene on the Y chromosome encodes the male hormone testosterone, which leads to male sexual development. A)TRUE FALSE A) in Anaphase of Meiosis 8) in Anaphase of Meiosis B C) in Anaphase of Micos DI A and 8 only @w8,and ? 7. In genetic epistasis, the gene that does the masking is referred to as thegene, and the gene that is masked is referred to as the .gene. A) epistatic; allostatic B) hypostatic; epistatic C) hypostatic; allostatic D) allostatic; epistatic epistatic; hypostatic 8 If a single locus has & distinct alleles, the number of possible unique genotyees to describe this locus is: A) 6 1 C115 D)3 E)42 20 (Us)/2Explanation / Answer
Q1) susumu ohno proposed that dosage compensation in placental mammal , occurs via interaction of a single X chromosome.
Answer- C- Susumu ohno.
Explanation- 1959 Susumu Ohno proved that the satellite-like structures found in placental mammals specially in female cells were derived from the female X chromosomes.
Q2) ________ who proposed the theory of chromosomal nondisjunction, was a student of _________.
Answer- E- calvin bridge, T.H.Morgan.
Explanation- According to Bridges during nondisjunction in the females, their two X chromosomes do not separate to form normal eggs with a single X chromosome each, rather nondisjunction creates eggs either having two X chromosomes or with nil X chromosomes.T.H. Morgan was the mentor of Calvin Bridge , he was doing his PHD work under him on drosophila.
Q3) The system for sex determination for bees , wasps and ants is referred to as __________ in which haploid _____ generates gametes via mitosis.
Answer- D- Haplodiploidy , males.
Explanation- In Bees , wasps and ants the system of sexdetermination is haplodiploidy, in it males develop from unfertilized eggs and are haploid, and females develop from fertilized eggs and are diploid. In this system, sex is determined by the number of sets of chromosomes a particular organism receives.
An offspring developed from the union of a sperm and an egg becomes a female, and an unfertilized egg develops as a male. Here males have half the number of chromosomes compared to a female , and are haploid.
Q4)The father of fruit fly genetics is ______.
Answer- E- T.H. Morgan.
Explanation-American embryologist Thomas Hunt Morgan is considered as the father of Drosophila or fruit fly genetics.
Q5) The SRY gene on the Y chromosome encodes the male hormone testosterone, which leads to male sexual development.
Answer- B- False.
Explanation- SRY is a gene found on the short branch of Y chromosomes , it helps in the development of primary male characters like testis . It initiates male embryonic development in XY sex determination system. In the Leydig cells, Sf1 activates the genes encoding the enzymes which makes testosterone.
Q6) Chromosomal nondisjunction can occur __________.
Answer-
Explanation- E- A,B,C.
Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division. There are three forms of nondisjunction1) Failure of a pair of homologous chromosomes to separate In anaphase of meiosis I, when nondisjunction occurs one cell has two copies of a chromosome,and the other cell has no copies. When each of these cells divide into two cells during meiosis II, the four cells produced will be having chromosomal abnormalities.
II) Failure of sister chromatids to separate during anaphase of meiosis II, after division ,one daughter cell will have an extra chromosome and one daughter cell will be missing a chromosome.
III) Failure of sister chromatids to separate during anaphase of mitosis.(when nondisjunction occurs, the chromatids do not separate. as a result one cell receives both chromatids,but the other cell do not receive any).
Q7) In genetic epistasis, the gene that does the masking is referred as the __________ gene, and the gene that is masked is referred as the _________gene.
Answer- E- epistatic, hypostatic.
Explanation - In epistasis the gene which masks is called the epistatic gene , and which is masked is hypostatic gene.
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