Home
Class 12
BIOLOGY
Select the correct statements (s) regard...

Select the correct statements (s) regarding the structure of a mature embryo sac.
(i) Egg apparatus is situated towards chalzal end.
(ii) Antipodal cells are situated towards micropylar end.
(iii) A typical angiospermic embryo sac is 7-celled, 8-nucleate at maturity

A

(i) only

B

(ii) only

C

(iii) only

D

(i),(ii) and (iii)

Text Solution

Verified by Experts

The correct Answer is:
C
In angiosperms, the female gametophyte (or embryo sac) is an oval multicellular haploid structures which is embedded in the nucellus towards micropylar half of the ovule. A typical and most common type of embryo sac, found in `80%` flowering plants is called Polygonum type of embryo sac. it contains 8 nuclei but 7 cells -3 micropylar, 3- chalazal and one central. it is formed by one meiosis and three mitosis. The three micropylar cells are collectively known as egg apparatus. The three chalazal cells of the embryo sac are called antipodal cells.
Promotional Banner

Similar Questions

Explore conceptually related problems

Select the correct statements regarding the characteristics of acquired immunity. (i) Cell-mediated immunity is responsible for acquired immunity. (ii) It produces a primary response of low intensity. (iii) Active and passive immunity are types of acquired immunity, (iv) Polymorphonuclear leucocytes and natural killer cells are involved in acquired immunity.

Which of the following statements regarding the structure of microsporagium are correct ? (i) Microsporangium is generally surrounded by four wall layers-epidermis, endothecium, middle layers and tapetum (ii) outer three layers perform functions of protection and dehiscence of anthers. (iii) Cells of tapetum undergo meiosis and produce micropore tetrads.

Read the following statements regarding arithmetic growth and select the correct answer. (i) Rate of growth is constant. (ii) One daughter cell remains meristematic while the other one differentiates and matures. (iii) Mathematical expression is L_(t) = L_(0) +rt .

Read the following statement regarding bryophytes and select the correct answer. (i). Bryophytes lack true roots, stem and leaves. (ii). The main plant body is haploid (iii). Sex-organs are unicellular and non-jacketed (iv). Fertilisation produces an embryo inside the water.

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.

Read the following statements and select the correct ones. (i) Same kind of sticky ends are produced when a DNA has been cut by different restriction enzymes. (ii) Exonucleases make cuts at specific positions within the DNA. (iii) Hind ll was the first restriction endonuclease to be isolated. (iv) A bacteriophage has the ability to replicate within bacterial cells by integrating its DNA with bacterial DNA. (v) Presence of more than one recognition sites for a enzyme within the vector facilitates the gene cloning.

Consider the following statements. (i) Polyspermy may bring about fertilisation of egg by more than one male nucleus or the supernumerary sperms may fertilise other components of embryo sac much as synergids or antipodals. (ii) In angiosperms, pollen tube is normally an unbranched structure which ususally persists after fertilisation. (iii) Intine is the inner, pectocellulosic layer of pollen grain wall which is destroyed during acetolysis. (iv) Exine layer of pollen grain comprises of an outer non-sculptured layer sexine and an inner sculptured layer tectum. Which of the following combinations of above given statements is correct ?

Study carefully the following stages of life cycle of malarial parasite i.e., Plasmodium. Arrange these stages in the correct sequence and select the correct answer. 1. Sporozoites leave the blood stream and enter the liver cells of man. 2. Sporozoites present in the salivary glands of female Anopheles mosquito are injected into the blood stream of man. 3. The parasite reproduces asexually in RBCs, resulting in bursting of RBCs and causing the cycles of fever, relased parasites infect new RBCs. 4. The parasite reproduces asexually in liver cells, ultimately causing the rupturing of cells. 5. Two types of gametocytes i.e., microgametocytes and macrogametocytes develop in the RBCs. 6. Female Anopheleles mosquito takes up the gametocytes with blood meal of an infected person. 7. Mature infective stage of the parasite i.e., sporozoites escape from intestine and migrate to the mosquito's salivary glands. 8. Fertilisation and developmental stages of the parasite take place in mosquito's stomach.

Read the given statements. (i) Flat membranous sacs in stroma of chloroplasts (ii) Infoldings in mitochondria (iii) Disc shaped sacs in Golgi apparatus Select the correct option as per the codes given above.