Test: Algae - 2

30 Questions MCQ Test Botany for Class 11 - Notes and Tests | Test: Algae - 2

Attempt Test: Algae - 2 | 30 questions in 30 minutes | Mock test for NEET preparation | Free important questions MCQ to study Botany for Class 11 - Notes and Tests for NEET Exam | Download free PDF with solutions

"Agar-agar" is obtained from :-

Solution: The gelling agent in agar is an unbranched polysaccharide obtained from the cell walls of some species of red algae, primarily from tengusa (Gelidiaceae) and ogonori (Gracilaria). ... In chemical terms, agar is a polymer made up of subunits of the sugar galactose.

Motile stages are not found in life cycle of :-

Solution: Blue green algae reproduce by simple division/fragmentation or nonmotile spores and do not exhibit any motile phase during the life cycle. Red algae (Rhodophyceae) are characterized by the absence of any motile phase. Brown algae (Pheophyceae) are characterized by the presence of motile reproductive phase with two lateral flagella. Green algae are characterized by unicellular flagellated cells or microscopic colonies of flagellated or non-flagellated cells and reproduce by zoospores. Thus, the correct answer is option C.

Embryo is not formed in thallophyta due to :-


Thallophyta (algae) reproduce sexually when male gametes and female gametes fuse to form zygote. Zygote immediately undergoes meiosis and it gives haploid gametes. Thus, embryo is not formed.
So, the correct option is 'Zygotic meiosis'.


Oogonia of Thallophyta differs with archegonia of bryophyta :-

In thallophytes, the female sex organ is a single-celled oogonium. It is not covered by any sterile jacket layer. In Bryophytes, the female sex organ is flask-shaped, multicellular archegonium which remains covered by a sterile jacket layer. Neck canal cells, ventral canal cell and egg are found within archegonium.
Thus, the correct answer is option D.

Which of the following best explains the evolution of sexual reproduction :-


Chlamydomonas is best example for the evolution of sexual reproduction as the evolution of sex in algae has not taken place in any one phylogenetic line. This has taken place along several independent lines. For example, in Volvocales, where Gonium is isogamous, Pandorina slightly anisogalnous, Eudorina and Pleodorina marked by anisogamy and Volvox oogamous. It is correlated with the evolution from isogamy to oogamy through anisogamy. Whereas on the other hand, in another genus of Volvocales, i.e., Chlamydomonas, where species within the genus show all gradations from isogamy to oogamy, e.g., Chlamydomonas snowiae is isogamous, C. braunii is anisogamous and C. coccifera is oogamous.  
Thus, the correct answer is option A.


Cephaleuros, which causes "Red rust of tea" is a :-

Solution: Cephaleuros virescens (= Cephaleuros parasiticus) is a parasitic green alga which causes the disease 'red rust of tea' in tea plants and 'leaf spot disease of guava' in gauava plant. It also causes leaf spot diseases in other plants like mango, magnolia and coffee.

Heterotrichous habit is common among :-

Solution: Heterotrichous habit first discovered in Fristchiella that is Green alga that mean terrestrial alga.

Gametes are non-motile in :-

Solution: Bga typically has a thick, gelatinous cell wall. They lack flagella, but hormogonia of some species can move about by gliding along surfaces. ... So correct option is B.

Due to which pigment red algae are capable of surviving in deep sea :-

Solution: Red algae (Rhodophyceae) contain Chl a and d and main pigment is Phycoerythrin . Red algae are red due to Phycoerythrin.it helps in photosynthesis in great depth in ocean and also on surface of water.

Blue - green Agae resembles more closely to:-

Solution: Cyanobacteria resemble the eukaryotic algae in many ways, including morphological characteristics and ecological niches, and were at one time treated as algae, hence the common name of blue-green algae. Cyanobacteria may be unicellular or filamentous. Many have sheaths to bind other cells or filaments into colonies.

Which of the following statement is true for algae :-

Solution: The term thallus is a botanical term that refers to the body of a plant that does not have leaves, stems and roots. In botany, historically, this term has been applied to algae, fungi and the various divisions of bryophytes.

In which plant group reproductive organs are not enclosed in a layer of sterile cells:-

Solution: Solution Bryophytes and algae are both autotrophic, plant body is thallus-like and devoid of vascular tissues. Instead of roots, rhizoids are present for attachment and absorption purpose. Both algae and bryophytes have motile sperms and need water for fertilization. But bryophytes can be separated from algae (Thallophyta) because archegonium originated for the first time in bryophytes in the plant kingdom. It is a flask-shaped structure with swollen base called venter and upper elongated neck. The venter contains a venter canal cell and an egg cell. It is surrounded by one-celled thick sterile jacket layer. In algae, sex organs are non-jacketed and unicellular.

Classification of algae is mainly based up on :-


Classification of algae is mainly based upon the nature of their pigments.
Red Algae (Rhodophyceae) are characterized by the pigments - Phycoerythrin and Phycocyanin.
Brown Algae (Phaeophyceae) are brown due to the pigment Fucoxanthin.
Green Algae (Chlorophyceae) are characterized by pigments Chlorophyll-a, b, Carotenes, Xanthophyll. Hence option C is correct.


A prokaryotic autotrophic nitrogen fixing symbiont found in

Solution: It Is cycas besides paddy fields it also found in vegetative part of cycas ..And being a cyanobacteria it acts as a symbiont and readily perform activity of nitrogen fixation so cycad is more correct answer.

Female sex organ of algae is called :-


A species of yellow-green alga called Vaucheria sessilis is an example of a sexually reproducing alga. The reproductive structures consist of an antheridium, which contains male gametes, and two oogonia, which contain female gametes.


Change in colour of algae according to depth in sea is called :-

Solution:  Colour of red algae changes according to depth in sea this is called as Gaudikov's effect. When red algae are present on the surface of the sea then their colour is blue and when they are at the bottom, their colour is red.

Bioluminescence is a phenomenon associated with

Solution: Pyrrophyta refers to dinoflagellates. And gonyaulax and noctiluca are the dinoflagellates which show bioluminiscense.

Origin and evolution of sex in algae is best seen in


The green algae are a large, informal grouping of algae consisting of the Chlorophyta and Charophyta/Streptophyta, which are now placed in separate divisions, as well as the potentially more basal Mesostigmatophyceae, Chlorokybophyceae and Spirotaenia.


Cilia & flagella are absent in life cycle of :–

Solution: There is no motile stage found in life cycle of red algae and BGA i.e. cilia & flagella are absent. But in some algae, calcium carbonate is also present in the cell wall, due to which their thallus become stony.

Which algae best explains the evolution of sexual reproduction :–


Clamydomonas and Ulothrix in green algae best explains the evolution of sexual reproduction. 
The first sexuality was seen in the Clamydomonas and Ulothrix in the from of isogamy that the gamates formed were of plus and minus strains. Next evolution is seen is the ansiogamy that the gametes are of different size. Hence, the correct option is Option A. 
The further more advanced evolution in the sex repdroduction is seen in the red algae and brown algae. so the Options B and C are not correct.


Spermatia are male gametes of :–

Solution: The red algae, or Rhodophyta from Ancient Greek ῥόδον (rhodon), meaning 'rose', and φυτόν (phyton), meaning 'plant'), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing.The majority of species (6,793) are found in the Florideophyceae (class), and mostly consist of multicellular, marine algae, including many notable seaweeds The nonmotile male gametes (spermatia) are produced singly in male sex organs, the spermatangia. Fertilization occurs when a male spermatium, carried by water currents, collides with the extended portion of a female carpogonium and the two gametes fuse.

 Cap cells occur in :-

Solution: Oedogonium filaments are typically unbranched and only one cell thick.  Asexual reproduction is by motile and nonmotile spores, formed only in cells with an apical cap. The motile reproductive bodies are characterized by a ring of cilia at the anterior end.

Algae which have food conducting tubes similar to phloem in vascular plants are :-

The division phaeophyta includes the brown algae. The division consists of about 2000 species, most of which are marine. The large sized brown algae are known as kelps. The largest brown algae attain a length of 40-60 meters. Brown algae are always multicellular. The brown algae contain the brown pigment fucoxanthim in addition to chlorophyll a and chlorophyll c. Their food reserves are lipid and laminarin. The large sized brown algae or kelps have food conducting tube, similar to phloem of vascular plants. They are termed trumpet hyphae. Brown algal cell walls are made of cellulose. Outside the cellulosic wall there is a colloidal covering consisting of a mixture of polysaccharides, called phycocolloids. It prevents drying or freezing of the alga. While some brown algae multiply by fragmentation, others reproduce by sexual means. Ectocarpus has isomorphic alternation of generation. Fucus is diploid and has diplontic type of life cycle. 


Chlorophyll 'c' , 'd' and 'e' are characteristic pigments of respectively :-


The brown algae contains xanthophyll pigment fucoxanthin, chlorophyll 'a' and 'c' (no chlorophyll b), beta-carotene. 
Red algae contain chlorophyll  'a'  and 'd' as well as phycobilins, red and blue pigments involved in photosynthesis. 
Yellow green algae contains chlorophyll 'a' but lack chlorophyll 'b'. They possess chlorophylls 'e' or 'c'. Besides these they also possess xanthophylls and beta carotene.
Therefore, the correct answer is option B.


Which of the following algae produces synzoospores :-

Solution: Vaucheria exhibits apical growth from the tip of filaments forming mats in either terrestrial or freshwater environments. Its filaments form coenocytes with a large central vacuole pushing against the surrounding cytoplasm; the vacuole extends along the entire filament except for the growing tip.The chloroplasts are located on the periphery of the cytoplasm with the nuclei aggregating toward the center near the vacuole.

Reserve food of algae and fungi are :-

Solution: Starch is stored in plants as food reserve. Starch is present in two forms- Amylose- which is linear chain of glucose and Amylopectin is a branched chain polymer of glucose Algae are chlorophyll-bearing, simple, thalloid, autotrophic and largely aquatic (both. fresh water and marine) organisms. They occur in a variety of other habitats: moist stones, soils and wood. Some of them also occur in association with fungi (lichen) and animals.

About 90 percent of total photosynthesis in the world is caused by :-


The fact that the land surface is covered in plants, not algae, indicates that plants are the most effective photoautotroph in most terrestrial habitats. In the open ocean, however, you will find mostly microalgae and some cyanobacteria, such as Prochlorococcusare particularly numerous. If you are wondering why these algae, which have a higher photosynthetic efficiency (measured as carbon fixed per quantity of photons), lose out to plants on land, then the short answer is that efficiency very rarely confers a reproductive or competitive advantage in biology.
As for why cyanobacteria and microalgae are more efficient at photosynthesis, it is mostly because they are small, (usually) single-celled, and have a enzymes to actively pump carbon dioxide into their cells (plants rely on passive diffusion). Being small gives them a very high surface-to-volume ratio. Being single-celled means that all cells are doing photosynthesis as opposed to a plant which needs to feed non-photosynthetic tissues. The carbon dioxide pumping enzymes lets cyanobacteria and microalgae avoid some of the harmful byproducts of photosynthesis that accumulate when there isn’t enough carbon dioxide in the cell to match the supply of energy from the light reactions.


Which type of algae are helpful in nitrogen economy :-

Solution: Option B because Blue green algae can fix nitrogen in their specialised cell known as heterocyst .

Sea weeds belong to :-

Solution: A seaweed may belong to one of several groups of multicellular algae: the red algae, green algae, and brown algae.

Plants of thallophyta are :-

Solution: Kingdom Plantae includes green, brown and red algae, liverworts, mosses, ferns and seed plants with or without flowers. ... Algae lack embryo stage. Life cycle consists of alternating haploid gametophyte and diploid sporophyte generation. This phenomenon is called alternation of generation.
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