The hormone responsible for the ripening of fruits is:
A. Gibberellin
B. Ethylene
C. Cytokinin
D. Auxin
Answer: Option B
Solution (By JKExamLibrary)
Ethylene is a gaseous plant hormone that promotes fruit ripening (climacteric fruits like banana, apple), leaf abscission, and senescence. Auxin, gibberellin, and cytokinin primarily promote growth. Ethylene is used commercially to ripen fruits uniformly. It also stimulates the formation of abscission layers and inhibits stem elongation.
Explanation:
A mature embryo sac (female gametophyte) in angiosperms is 7-celled but 8-nucleate: 3 antipodal cells (3 nuclei), 2 synergids (2 nuclei), 1 egg cell (1 nucleus), and 1 central cell with 2 polar nuclei. Thus total 8 haploid nuclei. The central cell is homodiploid (2 polar nuclei). Double fertilization involves these nuclei. This is typical of Polygonum type of development.
Explanation:
Phenylketonuria (PKU) is an autosomal recessive disorder due to deficiency of phenylalanine hydroxylase, leading to accumulation of phenylalanine, causing mental retardation if untreated. Albinism is tyrosinase deficiency, sickle cell HbS mutation, cystic fibrosis CFTR defect.
Consider the following statements about the blood:
1. Plasma is about 55% of blood volume.
2. Albumin is the most abundant plasma protein.
3. Red blood cells have nuclei in humans.
Which of the above is/are correct?
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