Test: Ulothrix (Pond Wool)


45 Questions MCQ Test Biology Class 11 | Test: Ulothrix (Pond Wool)


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QUESTION: 1

A motile flagellate asexual cell is known as -

Solution:

Asexual reproduction in algae is by production of different types of spores,the most common being the Zoospores. They are flagellated (motile) and on germination gives rise to new plants.

QUESTION: 2

Ulothrix is a green algae because-

Solution:

The above mentioned pigments produce the colour of green. 

QUESTION: 3

Ulothrix produces

Solution:
QUESTION: 4

The organ by which Ulothrix is attached to its substratrum is called a-

Solution:

Ulothrix is a genus of filamentous green algae, generally found in fresh and marine water. Its cells are normally as broad as they are long, and they thrive in the low temperatures of spring and winter. They become attached to surfaces by a modified holdfast cell. Reproduction is normally vegetative.

QUESTION: 5

The number of flagella in the gametes of Ulothrix is -

Solution:

Zygospore undergoes zygotic meiosis and forms 4 haploid nuclei of which three degenerate. So one haploid nuclei take part and one new filament is formed.

QUESTION: 6

The non-motile, highly thickened asexual spores are called-

Solution:

Chlamydomonas is a motile unicellular alga and belongs to the genus of green algae. This is found in stagnant water, freshwater, seawater, damp soil and even in snow. Asexual reproduction in algae takes place through the production of spores. When zoospores lose their motility these are referred to as aplanospores and in certain green algae these aplanospores have thickened walls and are known as hypnospores. These are resting spores released in the dormant state. 

Therefore, the correct answer is option A

QUESTION: 7

The basal cell of Ulothrix is devoid of-

Solution:

The cells of the filaments are arranged end to end. They are barrel-shaped or cylindrical in shape. The apical cell is somewhat rounded at its terminal end whereas, the basal cell is elongated and does not have chlorophyll. It is also called as the basal holdfast, which attaches the filament to the substratum.

QUESTION: 8

In Ulothrix reduction division occurs-

Solution:

Reduction division is nothing but meiosis. In Ulothrix, reduction division occurs at the time of zygospore germination.

QUESTION: 9

The species of Ulothrix preferring Salty water is-

Solution:

Ulothrix is a genus of green algae in the family Ulotrichaceae. Ulothrix is a genus of filamentous green algae, generally found in fresh and marine water.

QUESTION: 10

The akinete formed during unfavourable conditions in the Ulothrix life cycle is-

Solution:

An akinete is an enveloped, thick-walled, non-motile, dormant cell formed by filamentous, heterocyst-forming cyanobacteria under the order Nostocales and Stigonematales. Once conditions become more favorable for growth, the akinete can then germinate back into a vegetative cell.

QUESTION: 11

Which cell of Ulothrix does not divide-

Solution:

Ulothrix is a genus of filamentous green algae, generally found in fresh and marine water. Its cells are normally as broad as they are long, and they thrive in the low temperatures of spring and winter. They become attached to surfaces by a modified holdfast cell. Reproduction is normally vegetative.

QUESTION: 12

In Ulothrix, colony formation occurs during-

Solution:

Asexual reproduction takes place in winter, during its active growth. It takes place by the formation of zoospores, akinetes and palmella stage. a.The protoplast either develops into single zoospore (U. fimbriata) or undergoes division and form 2, 4, 8, 16 or 32 units.

QUESTION: 13

In Ulothrix, eye spot does not occurs in-

Solution:

The eyespot or stigma is a photoreceptive organelle found in the flagellate of green algae like Chlamydomonas and some other unicellular photosynthetic organisms such as euglenoids. It allows the cells to sense light direction and intensity and respond to it by swimming either towards the light (positive phototaxis) or away from the light (negative phototaxis). A related response occurs when cells are briefly exposed to high light intensity, causing the cell to stop, briefly swim backward, then change swimming direction. Eyespot-mediated light perception helps the cells in finding an environment with optimal light conditions for photosynthesis. Eyespots are the simplest and most common "eyes" found in nature, composed of photoreceptors and areas of bright orange-red pigment granules. Signals relayed from the eyespot photoreceptors result in alteration of the beating pattern of the flagella, generating a phototactic response.

QUESTION: 14

In Ulothrix, gametes are released in-

Solution:

Sexual reproduction of Ulothrix begins after the growth period/ Vegetative season. Sporophytic generation is represented only by the zygote. In the life cycle of Ulothrix, Zygote is very short in duration. Gametes are formed in semi drying condition and released in the morning.

QUESTION: 15

Which type of spores fix to substratum by anterior end at the time of germination-

Solution:

When zoospores settle on any substratum, the cysts almost invariably germinate towards the host. This raises the possibility that zoospores might pre- align during encystment.
Calcium has an important role in zoospores motility. It is also required for cyst adhesion and subsequent cyst germination.

QUESTION: 16

If Ulothrix is removed from water and placed in dry soil then it will produce-

Solution:

An akinete is formed under an unfavourable condition. It is an enveloped, thick- walled, non- motile, dormant cell formed by filamentous, heterocyst- forming cyanobacteria, ulothrix under the order Nostocales and Stigonematales. Akinetes are resistant to cold and desiccation.

QUESTION: 17

When single thick walled aplanospore is produced in a cell of Ulothrix it is called-

Solution:

Hypnospores: Under certain conditions the aplanospores secrete thick walls around them and store abundant food reserves. These thick walled aplanospores are called the hypnospores. Because of the thick wall, hypnospore may undergo a long resting period and may survive even in some unfavourable conditions (Ulothrix).

QUESTION: 18

Which type of gametes are produced in Ulothrix-

Solution:

In most species, all the cells can form reproductive bodies. Ulothrix reproduces vegetatively by fragmentation, asexually by nonmotile resting spores (aplanospores) and motile quadriflagellate spores (zoospores), and sexually by biflagellate gametes.

QUESTION: 19

Ulothrix is-

Solution:

Ulothrix is heterothallic. It means fusing isogametes have different strains genetically. Sexual reproduction of Ulothrix begins after the growth period/ Vegetative season.

QUESTION: 20

Ulothrix inhabits-

Solution:

Ulothrix is a genus of filamentous green algae, generally found in fresh and marine water. Its cells are normally as broad as they are long, and they thrive in the low temperatures of spring and winter. They become attached to surfaces by a modified holdfast cell. Reproduction is normally vegetative.

QUESTION: 21

Cells of Ulothrix are-

Solution:

Filaments unbranched, attached by a single basal rhizoidal cell, or rhizoids arising from other cells. Cells cylindrical, longer or shorter; chloroplast parietal, girdle-shaped, usually lobed, encircling normally over three quarters of the cell, with one or more pyrenoids.

QUESTION: 22

Pyrenoids are composed of-

Solution:

Unlike carboxysomes, pyrenoids are not delineated by a protein shell (or membrane). A starch sheath is often formed or deposited at the periphery of pyrenoids, even when that starch is synthesised in the cytosol rather than in the chloroplast.

QUESTION: 23

Why Ulothrix is not considered a linear colony of cells-
Hint : In a colony cells mechanically held together generally in a gelatinous envelope. The cells in the colony have little or no dependence upon one another

Solution:

Linear means no connections.
But Ulothrix is having plasmodesmatal connections. They are the connections of cytoplasms of neighbouring cells established through the plasmodesmata. The plant cells exchange small molecules with their neighboring cells through these plasmodesmatal connections.

QUESTION: 24

Apical cell of thallus in Ulothrix is-

Solution:

The thallus of Ulothrix is multicellular, filamentous, unbranched and bright green in colour. All the cells of the filament are similar but basal cell and apical cell are different. The upper most or apical cell is somewhat dome-shaped and basal cell is elongated and narrow at the base.

QUESTION: 25

Chloroplast of Ulothrix is-

Solution:

Ulothrix is a genus of filamentous green algae which are found in marine and fresh waters habitats.
They have a single girdle-shaped or band-shaped chloroplast near the peripheral region of the cytoplasm (near the cell wall).
So, the correct answer is 'Girdle-shaped'.

QUESTION: 26

Hold-fast of Ulothrix is-

Solution:

The plant body consists of unbranched, uniseriate filaments. The cells of the filaments are arranged end to end. They are barrel-shaped or cylindrical in shape. The apical cell is somewhat rounded at its terminal end whereas, the basal cell is elongated and does not have chloroplast. It is also called as the basal holdfast, which attaches the filament to the substratum.
 

QUESTION: 27

Red eye spot of zoospores of Ulothrix is made up of-

Solution:

A red colour eyespot is found in zoospores for reception of light, which is made up of carotenoids (Hematochrome).

QUESTION: 28

The name "Palmella Stage" is after the name of a-

Solution:

The stage of Palmella occurs in the Chlamydomonas and Euglena. They are the green algae, and have 325 species all of which are the unicellular flagellates.

QUESTION: 29

How many mating types occur in Ulothrix-

Solution:

The gametangia then fuse into a zygosporangium. In other fungi, cells from two hyphae with opposing mating types fuse, but only the cytoplasm is fused (plasmogamy). The two nuclei do not fuse, leading to the formation of a dikaryon cell that gives rise to a mycelium consisting of dikaryons.

QUESTION: 30

Vegetative reproduction in Ulothrix takes place by-

Solution:

In most species, all the cells can form reproductive bodies. Ulothrix reproduces vegetatively by fragmentation, asexually by nonmotile resting spores (aplanospores) and motile quadriflagellate spores (zoospores), and sexually by biflagellate gametes.

QUESTION: 31

Lithophytic species of Ulothrix is-

Solution:

The genus Ulothrix includes about 30 species. Most of them are found in fresh water of tanks, ponds, lakes etc. The common fresh water species are U. aequalis, U. zonata etc. Some grow in saline water (marine) such as U. pseudoflacca and U. flacca. Species like U. flaaca grows in the intertidal region.
Another member U. implexa grows as lithophytes. They prefer to grow in cold water and are available from rainy season to spring. They disappear during summer months.

QUESTION: 32

In Ulothrix food is stored in the form of-

Solution:

The major carbohydrate storage product of red algae is a type of starch molecule (Floridean starch) that is more highly branched than amylopectin. Floridean starch is stored as grains outside the chloroplast.These polysaccharide compounds are always stored outside the chloroplast.

QUESTION: 33

Which type of sexual reproduction occurs in Ulothrix-

Solution:

In Ulothrix, sexual reproduction takes place by the fusion of biflagellate gametes from different filaments. Ulothrix like Chlamydomonas shows the simplest and primitive type of sexual reproduction or Isogamy where two morphologically identical flagellated gametes take part in fusion resulting in zygospores.
Therefore, the correct answer is option A.

QUESTION: 34

In Ulothrix, Zygote is initially-

Solution:

 Species of Ulothrix with narrow cells produce quadri flagellate zoospores of one kind. Some species with broader cells have 3 types of zoospores.
The zoospores are morphologically almost alike but differ in size, number of flagella and position of the eye spot.

QUESTION: 35

One celled sporophyte are found in-

Solution:

Ulothrix is a genus of filamentous green algae, generally found in fresh and marine water. Its cells are normally as broad as they are long, and they thrive in the low temperatures of spring and winter. They become attached to surfaces by a modified holdfast cell. Reproduction is normally vegetative.

QUESTION: 36

The zoospores of Ulothrix exhibit a closer resemblance to the thallus of -

Solution:
QUESTION: 37

Micro zoospores in Ulothrix are-

Solution:

Ulothrix, genus of filamentous green algae (family Ulotrichaceae) found in marine and fresh waters. Ulothrix reproduces vegetatively by fragmentation, asexually by nonmotile resting spores (aplanospores) and motile quadriflagellate spores (zoospores), and sexually by biflagellate gametes.

QUESTION: 38

How many zoospores are produced in a single cell of Ulothrix-

Solution:

Zoospores are formed during favourable condition with proper growth of the plant. Any cell except holdfast is capable of producing zoospores. During zoospore formation the protoplast becomes slightly contracted from the cell wall.The protoplast either develops into single zoospore (U. fimbriata) or undergoes division and form 2, 4, 8, 16 or 32 units. Each unit contains single nucleus and cytoplasm. These small units form zoospores.

QUESTION: 39

The type of zoospores not formed in Ulothrix are-

Solution:

In most species, all the cells can form reproductive bodies. Ulothrix reproduces vegetatively by fragmentation, asexually by nonmotile resting spores (aplanospores) and motile quadriflagellate spores (zoospores), and sexually by biflagellate gametes.

QUESTION: 40

How many chloroplast occur in Ulothrix cell-

Solution:

Ulothrix is a genus of filamentous green algae which are found in marine and fresh waters habitats. They have a single girdle-shaped or band-shaped chloroplast near the peripheral region of the cytoplasm (near the cell wall).

QUESTION: 41

The zoo gametangia and zoo sporangia of Ulothrix are-

Solution:

The spores are heterothallic. Morphologically they are similar to the microzoospores. They are produced in the sporangium in zoosporangium. Depending on species the number of gametes may be 8, 16, 32 or 64. Like, microzoospores are uninucleate, biflagellate and smaller in size.
The zygote takes rest for about 5- 9 months. After rest the nucleus of zygote (2n) undergoes meiosis and forms 4 haploid nuclei of different strains. The mitosis may follow the meiosis and forms 8 to 16 haploid nuclei.

QUESTION: 42

Parthenogenesis in Ulothrix forms a resting structure called-

Solution:

In Ulothrix, sometimes, the gametes fail to fuse, lose their flagella, and secrete a thick wall around them and are called parthenospores or azygospores. After rest, each parthenospore germinates directly into a new plant.

QUESTION: 43

The cause of polarity in Ulothrix is due to-

Solution:

Cell polarity refers to spatial differences in shape, structure, and function within a cell. Almost all cell types exhibit some form of polarity, which enables them to carry out specialized functions. The plant body consists of unbranched, uniseriate filaments. The cells of the filaments are arranged end to end. They are cylindrical or barrel-shaped. The apical cell is somewhat rounded at its terminal end whereas the basal cell is elongated. It is also called the basal holdfast, which attaches the filament to the substratum. Epithelial cells become polarized along the apical-basal axis. These include regulating the vectorial transport of ions across cell sheets during their barrier function as well as ensuring directionality during their secretory and absorptive functions.

QUESTION: 44

Which of the following reproductive structure is equivalent to a complete cells-

Solution:

An akinete is an enveloped, thick-walled, non-motile, dormant cell formed by filamentous, heterocyst-forming cyanobacteria under the order Nostocales and Stigonematales.Akinetes are resistant to cold and desiccation. They also accumulate and store various essential material, both of which allows the akinete to serve as a survival structure for up to many years. However, akinetes are not resistant to heat. Akinetes usually develop in strings with each cell differentiating after another and this occurs next to heterocysts if they are present.

QUESTION: 45

Ulothrix is-

Solution:

Ulothrix is a genus of filamentous green algae, generally found in fresh and marine water. Its cells are normally as broad as they are long, and they thrive in the low temperatures of spring and winter. They become attached to surfaces by a modified holdfast cell. Reproduction is normally vegetative.

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