DOCSLIB.ORG

Plant Kingdom Dpp. No.-03

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Plant Kingdom Dpp. No.-03 BIOLOGY Daily Practice Problems MEDICAL ENTRANCE - 2020 CLASS : XI TOPIC : PLANT KINGDOM DPP. NO.-03 SECTION - A Q.1 Identify A, B, C, D & E in given diagram. Answer : A. ________ A B. ________ C. ________ D. ________ B E. ________ C D E Q.2 Identify A, B & C in given diagram. Answer : A A. ________ B. ________ C. ________ B C Q.3 Identify A, B & C in given diagram. Answer : A. ________ B. ________ C. ________ A B C Q.4 (i) Identify A & B. (ii) Which stage show by part (1) & (2) Answer : A A. ________ B B. ________ (1) (2) Q.5 (i) Identify A & B in given diagram. (ii) What is syngamy. A Answer : A. ________ B. ________ (1) B (2) Q.6 Identify A, B & C in given diagram. Answer : B A. ________ B. ________ A C. ________ SECTION - B Q.7 The sporophytes bear sporangia that are subtended by leaf-like appendages called ________. Q.8 In majority of the pteridophytes all the spores are of similar kinds; such plants are called ________. Q.9 The cones bearing megasporophylls with ovules or ________ are called macrosporangiate or ________. Q.10 The nucellus is protected by envelopes and the composite structure is called an ________. Q.11 Unlike the gymnosperms where the ovules are naked, in the angiosperms or flowering plants, the pollen grains and ovules are developed in specialised structures called ________. Q.12 Within ovules are present highly reduced female gametophytes termed ________. Q.13 The dominant, photosynthetic phase in such plants is the free-living gametophyte. This kind of life cycle is termed as ________. Q.14 The gametophytic phase is represented by the single to few-celled haploid gametophyte. This kind of lifecycle is termed as ________. SECTION - C Q.15 In most of the brown algae asexual reproduction takes place by - (1) Auxospores (2) Aplanospores (3) Pear shaped/pyriform biflagellate zoospores (have lateral, unequal flagella) (4) Multifagellate zoospore Q.16 In brown algae the gametes are - (1) Only isogametes (2) Only coenaplanogamete (3) Only multiflagellate gamete (4) Pyriform/pea shaped gametes having unequal 2 laterally attached flagella Q.17 Which one is correct about sexual reproduction in brown algae? (1) Sexual reproduction may be isogamy anisogamy or oogamy (2) In isogamy and oogamy fertilization is external (in water) (3) In oogamy fertilization occurs in oogonium (4) All are correct Q.18 Which of the following is correct? (1) In brown algae as well as red algae vegetative reproduction takes place by fragmentation (2) In red algae algal predominant pigments is r- phycoerythrin (3) Reserved food, floridean starch in red algae is very similar to amylopectin and glycogen in structure (4) All are correct Q.19 Chl a + Chl d + r-phycoerythrin are the pigments in the members of - (1) Rhodophyceae (2) Phaeophyceae (3) Chlorophyceae (4) Cyanophyceae Q.20 Which of the following statements does not characterize the red algae - (1) Floridean starch (reserve food) (2) Both spores and gametes are nonmotile (3) Post fertilization development is like other algae (4) Red algae can vary their ratio of photosynthetic pigments depending upon the light conditions Q.21 Porphyra and Polysiphonia belong to- (1) Chlorophyceae (2) Rhodophyceae (3) Xanthophyceae (4) Phaeophyceae Q.22 Bryophytes include- (1) Mosses (2) Lycopods (3) Horse tail (4) Liverworts+mosses Q.23 Bryophytes mostly grow - (1) in dry area (2) In snow (3) In moist shaded areas in hills, damp+humid+shaded localities (4) In water Q.24 Bryophytes are called “Amphibians of the plant kingdom” because- (1) They are found in only water (2) Plants live in soil but are dependent on water for sexual reproduction (3) It needs water for spores formation (4) Water is essential for its survival Q.25 Plant body of bryophyte is- (1) Less differentiated than that of algae (2) Equally differentiated to that of Algae (3) More differentiated to that of algae (4) Is not differentiated at all Q.26 The plant body of bryophytes is thallus-like and prostate or erect, and attached to substratum by - (1) Unicellular roots (2) Multicellular roots (3) Unicellular or multicellular rhizoids (4) Adhesive Q.27 The plant body of all bryophytes are gametophyte, haploid and thallus like having- (1) Root + Stem + Leaf (2) No root + no stem + no leaf (3) Xylem and phloem (4) Wood Q.28 The gametophytes in bryophytes produces biflagellate gametes (antherozoids) in__________and pro- duces ovum (female gamete) in___________. (1) Antheridium, carpogonium (2) Anther, ovary (3) Archegonium, antheridium (4) Antheridium, archegonium Q.29 Choose the correct option - (1) In bryophytes sexual reproduction is oogamous type (2) Sex organs are unicellular in algae and fungi but multicellular in bryophytes to angiosperms (3) Archegonium is flask shaped (4) All Q.30 Which is the prominent phase in the life cycle of bryophytes - (1) Gametophyte (2) Sporophyte (3) Seta (4) Sporogonium.
Load more

Recommended publications
  • Evolutionary Trajectories Explain the Diversified Evolution of Isogamy And
    Evolutionary trajectories explain the diversified evolution of isogamy and anisogamy in marine green algae Tatsuya Togashia,b,c,1, John L. Barteltc,d, Jin Yoshimuraa,e,f, Kei-ichi Tainakae, and Paul Alan Coxc aMarine Biosystems Research Center, Chiba University, Kamogawa 299-5502, Japan; bPrecursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan; cInstitute for Ethnomedicine, Jackson Hole, WY 83001; dEvolutionary Programming, San Clemente, CA 92673; eDepartment of Systems Engineering, Shizuoka University, Hamamatsu 432-8561, Japan; and fDepartment of Environmental and Forest Biology, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210 Edited by Geoff A. Parker, University of Liverpool, Liverpool, United Kingdom, and accepted by the Editorial Board July 12, 2012 (received for review March 1, 2012) The evolution of anisogamy (the production of gametes of dif- (11) suggested that the “gamete size model” (Parker, Baker, and ferent size) is the first step in the establishment of sexual dimorphism, Smith’s model) is the most applicable to fungi (11). However, and it is a fundamental phenomenon underlying sexual selection. none of these models successfully account for the evolution of It is believed that anisogamy originated from isogamy (production all known forms of isogamy and anisogamy in extant marine of gametes of equal size), which is considered by most theorists to green algae (12). be the ancestral condition. Although nearly all plant and animal Marine green algae are characterized by a variety of mating species are anisogamous, extant species of marine green algae systems linked to their habitats (Fig.
    [Show full text]
  • Uniparental Inheritance of Mitochondrial Genes in Yeast: Dependence on Input Bias of Mitochondrial Dna and Preliminary Investigations of the Mechanism
    UNIPARENTAL INHERITANCE OF MITOCHONDRIAL GENES IN YEAST: DEPENDENCE ON INPUT BIAS OF MITOCHONDRIAL DNA AND PRELIMINARY INVESTIGATIONS OF THE MECHANISM C. WILLIAM BIRICY, JR.*t, CATHERINE A. DEMKO*, PHILIP S. PERLMAN*t, AND ROBERT STRAUSBERwt The Ohio Stale University, Columbus, Ohio 43210 Manuscript received September 26, 1977 Revised copy received March 17, 1978 ABSTRACT In Saccharomyces cerevisiae, previous studies on the inheritance of mito- chondrial genes controlling antibiotic resistance have shown that some crosses produce a substantial number of uniparental zygotes, which transmit to their diploid progeny mitochondrial alleles from only one parent. In this paper, we show that uniparental zygotes are formed especially when one parent (major- ity parent) contributes substantially more mitochondrial DNA molecules to the zygote than does the other (minority) parent. Cellular contents of mito- chondrial DNA (mtDNA) are increased in these experiments by treatment with cycloheximide, alpha-factor, or the uvsp5 nuclear mutation. In such a biased cross, some zygotes are uniparental for mitochondrial alleles from the majority parent, and the frequency of such zygotes increases with increasing bias. In two- and three-factor crosses, the cupl, ery1, and oli1 loci behave coordinately, rather than independently; minority markers tend to be trans- mitted or lost as a unit, suggesting that the uniparental mechanism acts on entire mtDNA molecules rather than on individual loci. This rules out the possibility that uniparental inheritance can be explained by the conversion of minority markers to the majority alleles during recombination. Exceptions to the coordinate behavior of different loci can be explained by marker rescue via recombination. Uniparental inheritance is largely independent of the posi- tion of buds on the zygote.
    [Show full text]
  • The Rate of Facultative Sex Governs the Number of Expected Mating Types in Isogamous Species
    ARTICLES https://doi.org/10.1038/s41559-018-0580-9 The rate of facultative sex governs the number of expected mating types in isogamous species George W. A. Constable 1* and Hanna Kokko2 It is unclear why sexually reproducing isogamous species frequently contain just two self-incompatible mating types. Deterministic theory suggests that since rare novel mating types experience a selective advantage (by virtue of their many potential partners), the number of mating types should consistently grow. However, in nature, species with thousands of mat- ing types are exceedingly rare. Several competing theories for the predominance of species with two mating types exist, yet they lack an explanation for how many are possible and in which species to expect high numbers. Here, we present a theoretical null model that explains the distribution of mating type numbers using just three biological parameters: mutation rate, popu- lation size and the rate of sex. If the number of mating types results from a mutation–extinction balance, the rate of sexual reproduction plays a crucial role. If sex is facultative and rare (a very common combination in isogamous species), mating type diversity will remain low. In this rare sex regime, small fitness differences between the mating types lead to more frequent extinctions, further lowering mating type diversity. We also show that the empirical literature supports the role of drift and facultativeness of sex as a determinant of mating type dynamics. n most sexually reproducing species, gametes do not fuse indis- Our aim is to explain the preponderance of species with very criminately: syngamy only occurs between gametes of complemen- few mating types, as well as the existence of species with many tary mating types.
    [Show full text]
  • Evidence for Equal Size Cell Divisions During Gametogenesis in a Marine Green Alga Monostroma Angicava
    www.nature.com/scientificreports OPEN Evidence for equal size cell divisions during gametogenesis in a marine green alga Monostroma Received: 18 March 2015 Accepted: 03 August 2015 angicava Published: 03 September 2015 Tatsuya Togashi1, Yusuke Horinouchi1, Hironobu Sasaki2 & Jin Yoshimura1,3,4 In cell divisions, relative size of daughter cells should play fundamental roles in gametogenesis and embryogenesis. Differences in gamete size between the two mating types underlie sexual selection. Size of daughter cells is a key factor to regulate cell divisions during cleavage. In cleavage, the form of cell divisions (equal/unequal in size) determines the developmental fate of each blastomere. However, strict validation of the form of cell divisions is rarely demonstrated. We cannot distinguish between equal and unequal cell divisions by analysing only the mean size of daughter cells, because their means can be the same. In contrast, the dispersion of daughter cell size depends on the forms of cell divisions. Based on this, we show that gametogenesis in the marine green alga, Monostroma angicava, exhibits equal size cell divisions. The variance and the mean of gamete size (volume) of each mating type measured agree closely with the prediction from synchronized equal size cell divisions. Gamete size actually takes only discrete values here. This is a key theoretical assumption made to explain the diversified evolution of isogamy and anisogamy in marine green algae. Our results suggest that germ cells adopt equal size cell divisions during gametogenesis. Differences in sperm and egg size are evident in many animals and land plants1. However, variable mat- ing systems are also found in green algal taxa: 1) isogamy, where gamete sizes are identical between the two mating types, 2) slight anisogamy, where the sizes of male and female gametes are slightly different, and 3) marked anisogamy, where their sizes are markedly different2,3.
    [Show full text]
  • Evolution of the Two Sexes Under Internal Fertilization and Alternative Evolutionary Pathways
    vol. 193, no. 5 the american naturalist may 2019 Evolution of the Two Sexes under Internal Fertilization and Alternative Evolutionary Pathways Jussi Lehtonen1,* and Geoff A. Parker2 1. School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, 2006 New South Wales, Australia; and Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, 2052 New South Wales, Australia; 2. Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom Submitted September 8, 2018; Accepted November 30, 2018; Electronically published March 18, 2019 Online enhancements: supplemental material. abstract: ogy. It generates the two sexes, males and females, and sexual Transition from isogamy to anisogamy, hence males and fl females, leads to sexual selection, sexual conflict, sexual dimorphism, selection and sexual con ict develop from it (Darwin 1871; and sex roles. Gamete dynamics theory links biophysics of gamete Bateman 1948; Parker et al. 1972; Togashi and Cox 2011; limitation, gamete competition, and resource requirements for zygote Parker 2014; Lehtonen et al. 2016; Hanschen et al. 2018). survival and assumes broadcast spawning. It makes testable predic- The volvocine green algae are classically the group used to tions, but most comparative tests use volvocine algae, which feature study both the evolution of multicellularity (e.g., Kirk 2005; internal fertilization. We broaden this theory by comparing broadcast- Herron and Michod 2008) and transitions from isogamy to spawning predictions with two plausible internal-fertilization scenarios: gamete casting/brooding (one mating type retains gametes internally, anisogamy and oogamy (e.g., Knowlton 1974; Bell 1982; No- the other broadcasts them) and packet casting/brooding (one type re- zaki 1996; da Silva 2018; da Silva and Drysdale 2018; Han- tains gametes internally, the other broadcasts packets containing gametes, schen et al.
    [Show full text]
  • The Physics of Broadcast Spawning in Benthic Invertebrates
    MA06CH07-Crimaldi ARI 5 November 2013 12:41 The Physics of Broadcast Spawning in Benthic Invertebrates John P. Crimaldi1 and Richard K. Zimmer2 1Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, Colorado 80309-0428; email: [email protected] 2Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California 90095-1606; email: [email protected] Annu. Rev. Mar. Sci. 2014. 6:141–65 Keywords First published online as a Review in Advance on fertilization, turbulence, sperm, egg, flow, chemoattractant August 14, 2013 by John Crimaldi on 01/08/14. For personal use only. The Annual Review of Marine Science is online at Abstract marine.annualreviews.org Most benthic invertebrates broadcast their gametes into the sea, whereupon This article’s doi: successful fertilization relies on the complex interaction between the physics 10.1146/annurev-marine-010213-135119 of the surrounding fluid flow and the biological properties and behavior of Annu. Rev. Marine. Sci. 2014.6:141-165. Downloaded from www.annualreviews.org Copyright c 2014 by Annual Reviews. eggs and sperm. We present a holistic overview of the impact of instanta- All rights reserved neous flow processes on fertilization across a range of scales. At large scales, transport and stirring by the flow control the distribution of gametes. Al- though mean dilution of gametes by turbulence is deleterious to fertilization, a variety of instantaneous flow phenomena can aggregate gametes before di- lution occurs. We argue that these instantaneous flow processes are key to fertilization efficiency. At small scales, sperm motility and taxis enhance con- tact rates between sperm and chemoattractant-releasing eggs.
    [Show full text]
  • UNIT 4 REPRODUCTION in ALGAE Structure 4.1 Introduction Ol?Jeclives
    UNIT 4 REPRODUCTION IN ALGAE Structure 4.1 Introduction Ol?jeclives 4.2 Types of Reproduction ' Veghtivc l<cproduction Asexual Reproduction Sexual Reproduction 4.3 Reproductio~iand Life Cycle C'lilar~~ydo~~~onus ~l/o/liri.~ ~I/\~u Lai~iinorrcr , P rrcrrJ 4.4 Origin and Evolution of Sex Origin of Sex E:volution of Scx 4.5 Summary 4.6 Terminal Questions 4.7 Answers. 4.1 INTRODUCTION In unit 3 you have learnt that algae vary in size from small microscopic unicellular forms like Chlanzydonionas to large macroscopic multicellular forms like Lanzinaria. The multicellular forms show great diversity in their organisation and include filamentous. heterotrichous, thalloid and polysiphonoid forms. In this unit we will discuss the types ofreproduction and life cycle in algae taking suitable representative examples from various groups. Algae show all the three types of reproduction vegetative, asexual and sexual. Vegetative method solely depend on the capacity of bits of algae accidentally broken to produce a new one by simple cell division. Asexual methods on the other hand involve production of new type of cells, zoospores. In sexual reproduction gametes are formed. They fuse in pairs to form zygote. Zygote may divide and produce a new thallus or it may secrete a thick wall to form a zygospore. What controls sexi~aldifferentiation, attraction of gametes towards each other and determination of maleness or femaleness of ga~netes?We will discuss this aspect also. Yog will see that sexual reproduction in algae has many interesting features which also throw light on the origin and evolution of sex in plants.
    [Show full text]
  • Biology Day 3 Sexual Reproduction
    BIOLOGY DAY 3 SEXUAL REPRODUCTION FEATURES- 1. involves formation of the male and female gametes, either by the same individual or by different individuals of the opposite sex. 2 These gametes fuse to form the zygote which develops to form the new organism. 3 It is an elaborate, complex and slow process as compared to asexual reproduction. 4 Because of the fusion of male and female gametes, sexual reproduction results in offspring that are not identical to the parents or amongst themselves. 5 Phases- a)All organisms have to reach a certain stage of growth and maturity in their life, before they can reproduce sexually. That period of growth is the juvenile phase , known as vegetative phase in plants . b)The end of juvenile/vegetative phase which marks the beginning of the reproductive phase can be seen easily in the higher plants when they come to flower. Types of plants based on phases – a)the annual and biennial , show clear cut vegetative, reproductive and senescent phases, but in the b) perennial species it is very difficult to clearly define these phases. Unique features - 1) A few plants exhibit unusual flowering phenomenon - such as bamboo species flower only once in their life time, generally after 50-100 years, produce large number of fruits and die . 2) Strobilanthus kunthiana (neelakuranji), flowers once in 12 years Phases in animals-the juvenile phase is followed by morphological and physiological changes prior to active reproductive behaviour . birds living in nature lay eggs only seasonally. birds in captivity (as in poultry farms) can be made to lay eggs throughout the year .
    [Show full text]
  • The Evolution of Ogres: Cannibalistic Growth in Giant Phagotrophs
    bioRxiv preprint doi: https://doi.org/10.1101/262378; this version posted February 12, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Bloomfield, 2018-02-08 – preprint copy - bioRχiv The evolution of ogres: cannibalistic growth in giant phagotrophs Gareth Bloomfell MRC Laboratory of Molecular Biology, Cambrilge, UK [email protected] twitter.com/iliomorph Abstract Eukaryotes span a very large size range, with macroscopic species most often formel in multicellular lifecycle stages, but sometimes as very large single cells containing many nuclei. The Mycetozoa are a group of amoebae that form macroscopic fruiting structures. However the structures formel by the two major mycetozoan groups are not homologous to each other. Here, it is proposel that the large size of mycetozoans frst arose after selection for cannibalistic feeling by zygotes. In one group, Myxogastria, these zygotes became omnivorous plasmolia; in Dictyostelia the evolution of aggregative multicellularity enablel zygotes to attract anl consume surrounling conspecifc cells. The cannibalism occurring in these protists strongly resembles the transfer of nutrients into metazoan oocytes. If oogamy evolvel early in holozoans, it is possible that aggregative multicellularity centrel on oocytes coull have precelel anl given rise to the clonal multicellularity of crown metazoa. Keyworls: Mycetozoa; amoebae; sex; cannibalism; oogamy Introduction – the evolution of Mycetozoa independently in several diverse lineages, presumably reflecting strong selection for effective dispersal [9]. The dictyostelids (social amoebae or cellular slime moulds) and myxogastrids (also known as myxomycetes and true or The close relationship between dictyostelia and myxogastria acellular slime moulds) are protists that form macroscopic suggests that they shared a common ancestor that formed fruiting bodies (Fig.
    [Show full text]
  • Online Dictionary of Invertebrate Zoology: O
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Armand R. Maggenti Online Dictionary of Invertebrate Zoology Parasitology, Harold W. Manter Laboratory of September 2005 Online Dictionary of Invertebrate Zoology: O Mary Ann Basinger Maggenti University of California-Davis Armand R. Maggenti University of California, Davis Scott Gardner [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/onlinedictinvertzoology Part of the Zoology Commons Maggenti, Mary Ann Basinger; Maggenti, Armand R.; and Gardner, Scott, "Online Dictionary of Invertebrate Zoology: O" (2005). Armand R. Maggenti Online Dictionary of Invertebrate Zoology. 10. https://digitalcommons.unl.edu/onlinedictinvertzoology/10 This Article is brought to you for free and open access by the Parasitology, Harold W. Manter Laboratory of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Armand R. Maggenti Online Dictionary of Invertebrate Zoology by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Online Dictionary of Invertebrate Zoology 621 obliterate a. [L. obliteratus, erased] Indistinct. O oblong a. [L. oblongus, rather long] Elliptical; elongated; longer than broad. oblong plates (ARTHRO: Insecta) In aculeate Hymenoptera, the innermost or posterior pair of plates immovably fixed obconical a. [L. ob, inverse; conic, cone] Inversely conical; in on each side of the bulb and stylet of the sting. the form of a reversed cone. oblongum n. [L. oblongus, rather long] (ARTHRO: Insecta) In obcordate a. [L. ob, inverse; cor, heart] Inversely heart- Coleoptera wings, a special oblong cell formed when M 1 is shaped. connected with M 2 by means of one or two cross veins. obese a.
    [Show full text]
  • Mating Type Specific Roles During the Sexual Cycle of Phycomyces
    MATING TYPE SPECIFIC ROLES DURING THE SEXUAL CYCLE OF PHYCOMYCES BLAKESLEEANUS A DISSERTATION IN Cell Biology and Biophysics And Molecular Biology and Biochemistry Presented to the Faculty of the University of Missouri-Kansas City in partial fulfillment of the requirements for the degree DOCTOR OF PHILOSOPHY by Viplendra Pratap Singh Shakya Kansas City, Missouri 2014 © 2014 VIPLENDRA PRATAP SINGH SHAKYA ALL RIGHTS RESERVED MATING TYPE SPECIFIC ROLES DURING THE SEXUAL CYCLE OF PHYCOMYCES BLAKESLEEANUS Viplendra Pratap Singh Shakya, Candidate for the Doctor of Philosophy Degree University of Missouri - Kansas City, 2014 ABSTRACT Phycomyces blakesleeanus is a filamentous fungus that belongs in the order Mucorales. It can propagate through both sexual and asexual reproduction. The asexual structures of Phycomyces called sporangiophores have served as a model for phototropism and many other sensory aspects. The MadA-MadB protein complex (homologs of WC proteins) is essential for phototropism. Light also inhibits sexual reproduction in P. blakesleeanus but the mechanism by which inhibition occurs has remained uncharacterized. In this study the role of the MadA-MadB complex was tested. Three genes that are required for pheromone biosynthesis or cell type determination in the sex locus are regulated by light, and require MadA and MadB. However, this regulation acts through only one of the two mating types, plus (+), by inhibiting the expression of the sexP gene that encodes an HMG-domain transcription factor that confers the (+) mating type properties. This suggests that the inhibitory effect of light on mating can be executed through the plus partner. These results provide an example of convergence in the mechanisms underlying signal transduction for mating in fungi.
    [Show full text]
  • Introduction to Algae
    Algae are autotrophic, diverse group of eukaryotic organisms, ranging from unicellular to multicellular forms. Marine Algae Aquatic (fresh water and marine) and terrestrial environment. They also occur in moist stones, soils, wood, on snow and on ice. Algae on wood Microscopic Colonial forms unicellular eg. Chlamydomonas eg. Volvox Filamentous forms Marine forms eg.Ulothrix, Spirogyra eg. Kelps Reproduction in Algae Vegetative Asexual Sexual 1. Vegetative reproduction is by fragmentation. 2. Asexual reproduction is by the production of different types of spores, the most common being the zoospores. 3. Sexual reproduction takes place through fusion of two gametes. Gametes may be isogamy or anisogamy or oogamy. I. Isogamy - Fusion of two morphologically identical gametes. e.g. Spirogyra II. Anisogamy - Fusion of two dissimilar gametes, i.e., one gamete is smaller than the other. e.g. some species of Chlamydomonas III. Oogamy - Fusion between one large, non-motile female gamete and a smaller, motile male gamete. e.g. Volvox, Fucus Source of food Used as biofertilizer Sewage treatment Alternative to chemical dyes and colouring agents Commercial uses Agar 1. At least a half of the total carbon dioxide fixation on earth is carried out by algae through photosynthesis. 2. Major component in aquatic food chain as primary producers. 3. Porphyra, Laminaria and Sargassum are used as food. 4. Algin (brown algae) and carrageen (red algae) are used as hydrocolloids, which is a fibrous structure holds water and used to transport seedling. 5. Agar is used as commercial products. 6. Gelidium, Graularia are used to grow microbes, make ice creams and jellies. 7.
    [Show full text]