In Rhizopus, tubular thread like structures bearing sporangia at their tips are called :
Filaments
Rhizoids
Roots
Hyphae
(4)
In fungi, hyphae are filamentous structures that branch out and spread beneath a substratum’s surface. Hyphae may rise upright above the surface during its life cycle, with its contents forming a bulge at the tip. The sporangium is formed by this bulge. Spores are generated in the sporangium.
Factors responsible for the rapid spread of bread mould on slices of bread are
(i) large number of spores.
(ii) availability of moisture and nutrients in bread.
(iii) presence of tubular branched hyphae.
(iv) formation of round shaped sporangia.
(i) and (iii)
(ii) and (iv)
(i) and (ii)
(iii) and (iv)
(3)
The sporangium of the bread mould releases huge number of spores, which germinate on a suitable substratum and form hyphae. Fungi are saprophytes so profuse growth is only possible in the presence of an appropriate substratum, such as bread, that provides a considerable amount of moisture and nutrients.
The Ratio of Number of Chromosomes in a Human Zygote and a Human Sperm is:
2 : 1
3 : 1
1 : 2
1 : 3
(1)
The number of chromosomes in a human sperm is half the number of chromosomes in a zygote i.e., their ratio is 2 : 1.
A ______ fuses with a ______ in generative fertilisation.
Secondary nucleus, polar nucleus
Polar nucleus, female gamete
Male gamete, female gamete
All of the above
(3)
In double fertilisation, triple fusion (vegetative fertilisation) and syngamy (generative fertilisation) occur. In generative fertilisation, a male gamete fuses with a female gamete and forms diploid zygote.
Which of the statements is incorrect?
The filiform apparatus blocks the entry of pollen and sperm cells.
The secondary nuclei form a polar nucleus prior to fertilisation.
Androecium is a part of the carpel.
All of the above
(4)
Filiform apparatus are the finger-like projections that direct the entry of pollen tube and aid in sperm discharge. The definitive nucleus is a secondary nucleus generated by the fusion of two polar nuclei. Stamens are the male parts of a flower; together, they make up the androecium.
The anther contains :
Sepals
Ovules
Carpel
Pollen grains
(4)
Pollen grains are microscopic structures produced by an anther. When anther opens, pollen is released, which is subsequently transferred by the wind, insects, or birds to different plants for pollination.
What is the event after zygote formation called?
Pre-fertilisation
Post-fertilisation
Fertilisation
Gametogenesis
(2)
Sexual reproduction is divided into 3 events: Pre-fertilisation, fertilisation and post-fertilisation events. Pre-fertilisation events occur before fusion of gametes (gametogenesis), fertilisation is the fusion of gametes to form zygote and post-fertilisation events occur after zygote formation.
Anthers and filaments form the _____.
gynoecium
calyx
androecium
corolla
(3)
Androecium consists of the anthers and filaments. They are the male reproductive structures. Male gametes that are in pollen grains are on the anthers. Depending on the species, the stamens (anthers and filaments) may or may not protrude out of the flower.
The correct sequence of reproductive stages occurring in flowering plants is:
Gametes, Zygote, Embryo, Seed
Zygote, Gametes, Embryo, Seed
Seed, Embryo, Zygote, Gametes
Gametes, Embryo, Zygote, Seed
(1)
Gametes of flowers fuse to form a zygote. This zygote develops into an embryo that later forms the seed.
Identify A, B and C in the given diagram and match the labelling referred in column I and correlate with the function in column II.
| Column I | Column II |
|---|---|
| A. | (i) Special reproductive female sex cell which combines with male gamete to form zygote. |
| B. | (ii) A male gamete moves down through it towards the female gamete in the ovary |
| C. | (iii) Receiving the pollen grains from the anther of stamen during pollination. |
A-(iii), B-(ii), C-(i)
A-(ii), B-(i), C-(iii)
A-(i), B-(ii), C-(iii)
A-(iii), B-(i), C-(ii)
(1)
A – Stigma. The top part of carpel is called stigma. Stigma is for receiving the pollen grains from the anther of stamen during pollination.
B – Pollen tube. When a pollen grain falls on the stigma, it bursts open and grows a pollen tube downward through the style towards the female gamete in the ovary. A male gamete moves down the pollen tube.
C – Female gamete (ovum). It is a special reproductive female sex cell which combines with male gamete to form zygote.
