Free PDF download of Important Questions for CBSE Class 12 Biology Chapter 3 - Human Reproduction prepared by expert Biology teachers from the latest edition of CBSE (NCERT) books. These are named so because the sequence of base pairs reads same on the two strands when orientation of reading is kept the same. Tapetal nuclei are. All rights reserved. Draw a neat labelled diagram of a pollen sac. Male and female gametophytes are the two gametophytic stages of heterosporous plants. Justify with the help of an example where a deliberate attempt by humans has led to the extinction of a particular species. Free PDF download of Important Questions for CBSE Class 12 Biology Chapter 2 - Sexual Reproduction in Flowering Plants prepared by expert Biology teachers from the latest edition of CBSE (NCERT) books. When these gametes meet, they fuse together, get fertilized and form the zygote, which is diploid (2n). The naked seeds are noted. Each microspore mother cell undergoes meiosis to produce 4 microspores (male spores) 2. Identify A, D, E and F in the diagram of an antibody molecule given below. The term gametophyte may refer to the gametophyte phase of the plant life cycle or to the particular plant body or organ that produces gametes. Consider the following statements and choose the ones that … (i) Give the base sequence of its complementary strand. The adult gametophyte is differentiated into rhizoids, axis or ‘stem’ and ‘leaves’. 232, Block C-3, Janakpuri, New Delhi,
The gametophyte refers to all organs and tissues that are a part of the haploid generation. No enzyme that degrades sporopollenin is … This megaspore undergoes three successive mitotic divisions to form eight nucleate embryo sacs. Inside is a tiny, tiny plant. Ltd. The sporophyte stalk, called the seta, bears the spore capsule on its tip. ... Q22.Draw a f low chart to show hormonal control of human male reproductive system,highlighting the The central cell divides to produce a second primary prothallial cell and an antheridial initial. It has a haploid nucleus. Testis: The most important male reproductive organ is the testis, which produces sperms. (a) Identify (A) and (B) illustrations in the following:i. ii. View solution. View solution. gametophyte and sporop… Get the answers you need, now! The adult gametophyte is differentiated into rhizoids, axis or ‘stem’ and ‘leaves’. Q.9. Explain. Mosses are bryophytes and have no proper stem or roots. View solution.
(c) Alternation of generation in angiosperm female and male thallus of liverworts and b). There are two hydrogen bonds between adenine and thymine and three hydrogen bonds between guanine and cytosine. (c) Rhizoid: The hairy filaments growing in a cluster from the underground part of the stem are known as rhizoids. (a) Sickle celled anaemia in humans is a result of point mutation. This cycle is named alternation of generations and organisms alternate between a sexual phase, or gametophyte generation and an asexual phase, or sporophyte generation. Gametophyte contains balls of unspecialized cells called gammae. It then divides into two cells – one larger cell called a vegetative cell and a smaller cell called a generative cell. The nucleus of microspore divides mitotically to form a large vegetative cell and a small generative cell.The vegetative nucleus remains in the centre while the generative nucleus is attached to the wall of the pollen grain in the … 13. Practising given Class 12 Biology Chapterwise Important Questions with solutions will help in scoring more marks in your Board Examinations. It is eight nucleated, seven celled structure. Write any two advantages of inbreeding. Thus, a fully developed male- gametophyte consists of a disorganized prothallial cell, stalk cell, tube nucleus and 2 male gametes (Fig 9.13 ) Each male gamete appears top-shaped with 5-6 spiral bands of cilia. The female gametophyte (embryo sac) develops from a single functional megaspore. Gametophore: The part of the protonema developed erectly and enriched with leaves is known as gametophore protonema dies after the gametophore becomes fully developed. Microspore mother cells. Marchantia Archegonial Head Marchantia Archegonia with Eggs Eggs are produced within archegonia on the female gametophyte’s archegonial head. 4, 12 2. Best answer. Male gametophyte development in higher plants is a complex process that requires the coordinated participation of various cell and tissue types and their associated specific gene expression patterns. A male gamete of main part which involved in sexual reproduction in flowering plants. [Delhi 2011] Ans. Delhi - 110058. It is extensively used in the process of gene manipulation. It is in the haploid gametophyte structure that gametes are formed. View solution. Easy drawing of this item is shown in this video. https://www.zigya.com/previous-year-papers/CBSE/12/Biology/2011/CBSE2011004. male and female gametophyte; class-12; Share It On Facebook Twitter Email. The first division produces two nucleated embryo sac. Development of Female Gametophyte. The whole process of female gametophyte development occurs in two different phases. Both the alleles of a gene are equally dominant. Describe the development of female gametophyte in angiosperm . Their stickiness of the ends facilitates the action of the enzyme DNA ligase. The individual cells of the tetrad are released The male reproductive organs include the testes, seminal vesicles, penis and some associated glands such as the prostate gland. A . Draw a diagram of a male gametophyte of an angiosperm. 1.3k VIEWS. Male gametogenesis begins with the division of a diploid sporophytic cell, giving rise to the tapetal initial and the sporogenous initial (pollen mother cell). It is not only sustained by gene functions but by cellular functions as well that are encoded by accessory cells which can turn active genetically if there is a failure in the gametes. c. Alternation of generation in Angiosperm. In fully developed male gametophyte the number of nuclei is. It has two parts sporophyte and gametophyte. These two nuclei divide twice forming four nucleate and then eight nucleate structure. They are the most conspicuous part of the moss. Mention its importance in biotechnology. The female gametophyte in gymnosperms differs from the male gametophyte as it spends its whole life cycle in one organ, the ovule located inside the megastrobilus or female cone. 1.3k SHARES. Development of male gametophyte . In fully developed male gametophyte the number of nuclei is. A gametophyte represents the sexual phase of plant life. (b) The term used for A is Sticky ends, it is called so because they form hydrogen bonds with their complementary cut counterparts. Draw a well-labeled diagram of Polygonum type of embryo sac. (i) The base sequence of the complementary strand will be - ATCGTACTA. Although many genera are still completely unknown, it appears correct to state that on the whole the development of the male gametophyte within a family is quite uniform. For example, the allele for tall trait T is dominant over the trait for dwarfness t. Co-dominance: Co-dominance is the phenomenon in which both the alleles of a contrasting character are expressed in heterozygous condition. (b) Genotypes of parents who have produced a sickle celled anaemic offspring can be either. As the spore cracks, the spore cell divides asymmetrically , producing one lar ger basal cell and one 3:40 000+ LIKES. The sporophytes … Draw a labelled diagram of a Graafian follicle. (b) Write the genotypes of both the parents who have produced a sickle celled anaemic offspring. 1, 3 What is inbreeding depression and how is it caused in organisms? First, the microspore divides to produce a large central cell and a small first primary prothallial cell. The haploid microspore (pollen) is the pioneer structure of the male gametophyte. ) Draw well labeled diagram of mature female gametophyte of an angiosperm b) Make a list of post fertilization changes that occurs in the angiosperms c) How is apomixis different from parthenocarpy - Biology - Sexual Reproduction in Flowering Plants Similar to the male gametophyte, the female gametophyte normally is fully dependent on the surrounding sporophytic tissue for nutrients and the two organisms cannot be separated. Fertilization: Download the PDF Sample Papers Free for off line practice and view the Solutions online. 1. Female and male thallus of a liverwort. Examine (and draw and label) a prepared slide of the female archegonial head (Carolina #B325). Development of Male Gametophyte: Microspore represents the beginning of the male gametophyte. Following is the labelled diagram of a male gametophyte of an angiosperm.Sporopollenin is considered to be the most resistant organic material because it is chemically very stable and it can withstand high temperatures, acidic and alkaline conditions, and enzymes. C are called the palindromic nucleotide sequence. Sol: The pouch-like structures present in seed plants where pollen is produced. The term gametophyte might refer to the gametophyte phase of the plant life cycle or to the exacting plant body or organ that produces gametes. 2. In this disease, the gene coding for enzyme ADA gets deleted leading to deficiency of ADA and problems in immune system. Each leaf has a single midrib. Gene therapy for ADA deficiency includes isolation of lymphocytes from patient’s blood, culturing them in-vitro, introduction of functional ADA cDNA and returning the cells to the patient’s body. b. Gametophyte and sporophyte of Funaria. 2020 Apr;182(4):2006-2024. doi: 10.1104/pp.19.01254. Male gametophyte development. (b) Write the term given to (A) and (C) and why? View solution. Zhao H, Guo M, Yan M, Cheng H, Liu Y, She Z, Lai L, Shi C, Zhang M, Li Y, Lin D, Qin Y.Zhao H, et al.Plant Physiol. The term gametophyte may refer to the gametophyte phase of the plant life cycle or to the particular plant body or organ that produces gametes. Draw and label a simple diagram of alternating generations . Any vegetative cell of the sporophyte may form green protonemal filaments which bear lateral buds. Certain pollen chamber cells. The female gametophyte develops inside the ovule. Figure 1 illustrates the subsequent events leading to the formation of a pollen grain. The microspore starts germinating while it is still within the microsporangium or pollen sac. Spores are actually the first cells of the gametophyte generation. Draw the diagram of longitudinal section of datura flower and label its parts. Explain how oxygen concentration is affected in the river when sewage is discharged into it. No enzyme that degrades sporopollenin is so far known. This is caused due to an increase in the biological oxygen demand (BOD). (iii) Base Complementarity Rule: A purine always pairs with a pyrimidine in a DNA molecule i.e. Explain Archegonium or Female Reproductive Organ of Moss, Identifying Characteristics of Sub-family Papilionoideae, Perseverance Spotted From Space As Tiny Speck On Martian Surface, UN Climate Report Reveals World Is “Nowhere Close” To Curbing The Climate Emergency, This Is How Slime Mold Makes Memories, Despite Having No Brain, Leucism Or Albinism? The gametophyte refers to all organs and tissues that are a part of the haploid generation. development of male gametophyte is important step for plant reproduction. All … Development of gametophyte from sporophyte without the formation of spores is known as apospory. (i)The structure of a male gametophyte of an angiosperm is: (ii)Sporopollenin is one of the hardest or resistant organic material known. ... which contain the male gametophyte. (ii) The base pairs in the DNA molecules are held together by hydrogen bonds. The first mitotic division in the megaspore forms two nuclei.
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