Tag: structure of male and female reproductive structures

•Anatropous ovule is the most common type of ovules, which occurs in more than 80% of angiospermic families. The body of ovule is rotated by 180° and micropyle comes near to the funiculus. Chalaza and micropyle lie in the straight line but hilum is at 90° to the micropyle.

•Orthotropous ovule is the simplest and primitive type of ovule. In this type of ovule, micropyle, chalaza and funiculus lie in one vertical plane i.e. in a straight line.

•Hemianatropous ovule- The body of ovule is turned through 90° and micropyle and chalaza lie in a straight line but funiculus is at a right angle or 90° with both these two.

•Amphitropous ovule- Here, the body of ovule gets curved along with the embryo sac and it becomes horseshoe-shaped.

So, the correct answer is B.

In Circinotropous ovule, the length of the funiculus becomes increased and so it covers the whole ovule. Circinotropous ovule is found in the family Cactaceae. Example, Opuntia.

Ranunculus has Hemianatropous ovule in which body of ovule is turned through 90° and micropyle and chalaza lie in straight line but funiculus is at 90° to both of these.

Polygonum has Orthotropous ovule in which micropyle, chalaza and funiculus lie in a straight line.

Cicer has Anatropous ovule in which body of ovule is rotated by 180° and micropyle comes near to funiculus. Chalaza and Micropyle are in straight line but hilum is at 90° to the micropyle.

So, the correct answer is A.

•Hemianatropous ovule- The body of ovule is turned through 90° and micropyle and chalaza lie in a straight line but funiculus is at right angle or 90° with both these two.

•Amphitropous ovule- The body of ovule gets curved along with the embryo sac in such a way that it becomes horseshoe-shaped.

Thus, in Hemianatropous ovule, the body of ovule is straight as it doesn't get curved and is turned to 90° such that it is at right angle to the funiculus.

So, the correct answer is C

•Pollen grains develop from microspores. Microspores are formed from the microspore mother cell. Microspore mother cell is diploid and undergoes meiosis to produce four haploid microspores which develop to form pollen grains. Hence, pollen grains are haploid.

•Egg is the female gamete present in the embryo sac. Egg cell is haploid and on fusion with male gamete produces a diploid zygote. Hence, egg is haploid.

•Megaspore is formed from the megaspore mother cell. Megaspore mother cell is diploid and undergoes meiosis to produce four haploid megaspores. Hence, megaspore is haploid.

•MMC or Megaspore Mother Cell is a diploid cell which develops in the Nucellus of the ovule. MMC undergoes meiotic division to produce four haploid megaspores out of which, only one remains functional and the other three degenerate.

Hence, only MMC is diploid and rest are haploid structures.

So, the correct answer is D.

So the correct option is 'Megasporangium'.

• After fertilisation has occurred in the ovule, the ovule gets transformed into seed.

• Aril is a fleshy seed appendage which arise from the funiculus. It surrounds the ovule in the post fertilisation stages.

• After fertilization, the nucellus persists in the seed in the form of perisperm.

• Polar nuclei on fusion with the male gamete form a triploid primary endosperm mother cell which develops into endosperm.

Hence, the correct match is a- 3, b- 2, c- 4, d- 1

So, the correct answer is B.

• Amphitropous ovule- The body of ovule gets curved along with the embryo sac in such a way that it becomes horseshoe-shaped. This type of ovule is found in families like Butamaceae, Loganiaceae.

• Campylotropous ovule- This type of ovule is similar to Anatropous ovule but curvature is less than that of anatropous ovule. Campylotropous ovule is found in families like Chenopodiaceae. 

• Circinotropous ovule- In this type of ovule, the length of funiculus becomes increased and it covers the whole ovule. It is found in families like Cactaceae (Opuntia).

• Orthotropous ovule is the simplest and primitive type of ovule. In this type of ovule, micropyle, chalaza and funiculus lie in one vertical plane. Examples , all gymnosperms, Polygonum.

Hence, Opuntia has circinotropous ovule. So, the correct answer is C.

The cuticle is a waxy substance which fills the space between the Nucellus and inner integument and between the outer and inner integuments of the ovule. Both the integuments are covered with a layer of cuticle.

Hence, the cuticle is present over the outer part of integument.

So, the correct answer is A.

The process of formation of microspores from spore mother cells (SMC) or Microspore mother cell is called microsporogenesis. Very important changes occur in the Tapetum and locule of the anther during microsporogenesis. In the beginning, when the locule is preparing for microsporogenesis, there are plasmodesmatal connections between Tapetal and Tapetal cells, tapetal and SMC and between SMC and SMC. Very small molecules can pass through these connections. Towards the end of zygotene-pachytene stage of prophase I of meiosis, callose layer starts to get depositing around each SMC and the plasmodesmatal connections are cut off. This callose is contributed by the dictyosomes present in the peripheral cytoplasm of the microspore mother cell.

Hence, Microspore mother cells produces callose for breaking the plasmodesmatal connections among microspore mother cells.

So, the correct answer is A.

•Funicle is the stalk of ovule by which it adheres to the placenta.

•Integuments are the protective coverings of the ovule.

•Chalaza is the basal part of the ovule which is opposite to the micropyle.

•Hilum is a structure that attaches the body of the ovule to the funiculus i.e. stalk of the ovule.

•Micropyle is a small opening in the ovule through which pollen tube enters the ovule during fertilisation.

Hence, the correct match is:

1-b, 2-c, 3-e, 4-d, 5-a

So, the correct answer is A.