Plasmogamy is the fusion of
two haploid cells including their nuclei.
two haploid cells without nuclear fusion.
sperm and egg.
sperm and two polar nuclei.
Correct Answer :
B. two haploid cells without nuclear fusion.
Plasmogamy is the first stage of sexual reproduction in which the cytoplasm of two sex cells fuse with each other. The nuclei of sex cells come close to each other but do not fuse. Thus, the resulting cell becomes binucleate or dikaryon.
Related Questions
Protozons are not included in kingdom animalia because they are
mostly asymmetrical.
unicellular eukaryotes.
heterotrophic in nature.
multicellular prokaryotes.
The given characters are seen in which of the following group?
(i) Unicellular, colonial, filamentous, marine or terrestrial forms.
(ii) The colonies are surrounded by a gelatinous sheath.
(iii) Some can fix atmospheric nitrogen in specialized cells called heterocysts.
(iv) They often form blooms in water bodies.
Archaebacteria
Cyanobacteria
Chrysophytes
Dinoflagellates
Which of the following is a parasitic fungi on the mustard plant ?
Albugo
Puccinia
Yeast
Ustilago
Which of the following is an example of amoeboid protozoans ?
Trypanosoma
Paramecium
Gonyaulax
Entamoeba
Which one of the following is a characteristic feature of chrysophytes?
They are parasitic forms which cause diseases in animals.
They have a protein rich layer called pellicle.
They have indestructible wall layer deposited with silica.
They are commonly called dinoflagellates.
Bacteria were regarded to be plants because
some of them are green in colour.
they are present every where.
some of them cannot move.
they have a rigid cell wall.
Which of the following characteristic(s) is used by Whittaker for the classification of organisms ?
Mode of nutrition
Thallus organisation
Phylogenetic relationships
All of the above
Plasmogamy is the fusion of
two haploid cells including their nuclei.
two haploid cells without nuclear fusion.
sperm and egg.
sperm and two polar nuclei.
Which one single organism or the pair of organisms is correctly assigned to its taxonomic group?
Paramecium and Plasmodium belong to the same kingdom as that of Penicillium.
Lichen is a composite organism formed from the symbiotic association of an alga and a protozoan.
Yeast used in making bread and beer is a fungus.
Nostoc and Anabaena are examples of protista.
Which of the following statement is incorrect ?
TMV has a double-stranded RNA molecule.
Most plant viruses are RNA viruses.
The bacteriophage has a double-stranded DNA molecule.
Most animal viruses are DNA viruses.
A fungus contains cells with two nuclei from different genomes. The nuclei do not fuse but divide independently and simultaneously as new cells are formed. This fungus belongs to
phycomycetes
zygomycetes
deuteromycetes
basidiomycetes
Bacteria are found to be primitive organisms because they
are small, microscopic which are not seen with naked eye.
cause serious diseases to human being, domesticated animals and crop plants.
produce endospores which are very resistant to adverse conditions.
possess incipient nucleus and show amitotic division.
T. O. Diener discovered a new infectious agent that was smaller than viruses and have the following characteristics.
(i) It causes potato spindle tuber disease.
(ii) It has free RNA.
(iii) Molecular weight of RNA is low.
Identify the infections agent.
Viruses
Viroids
Virion
Mycoplasma
Why food can be kept for a longer time in cold house than in normal conditions ? Because,
insect cannot enter.
bacterial multiplication stops.
bacterial multiplication is reduced.
there is plasmolysis at low temperature.
When a moist bread is kept exposed in air, it becomes mouldy and black because
spores are present in the water.
spores are present in the bread.
spores are present in the air.
the bread decomposes.
Which of the following class of fungi is being described by the given statements ?
(i) They are found in aquatic habitats and on decaying wood in moist and damp places.
(ii) Mycelium is aseptate and coenocytic.
(iii) Asexual reproduction takes place by zoospores (motile) or by aplanospores (non-motile).
(iv) Some common examples are Mucor, Rhizopus and Albugo.
Ascomycetes
Phycomycetes
Basidiomycetes
Deuteromycetes
Which statement is not correct for viruses ?
Viruses are obligate parasites.
Viruses can multiply only when they are inside the living cells.
Viruses cannot pass through bacterial filters.
Viruses are made up of protein and DNA or RNA (never both DNA and RNA).
Which of the following is used extensively in biochemical and genetic work ?
Agaricus
Alternaria
Neurospora
Mucor
Fungi show asexual reproduction by all of the following kinds of spores except
conidia
oospores
sporangiospores
zoospores
Mycorrhizae are useful for plants because they
fix atmospheric nitrogen.
enhance absorption of nutrients from the soil.
kill insects and pathogen.
provide resistance against abiotic stresses.
Which of the following pigment is present in cyanobacteria?
Chlorophyll a
Chlorophyll b
Chlorophyll c
Chlorophyll d
A virus can be considered a living organism because it
responds to touch stimulus
respires
reproduces (inside the host)
can cause disease
Identify the following figures A, B and C.
A – Euglena, B – Paramecium, C – Agaricus
A – Euglena, B – Planaria, C – Agaricus
A – Planaria, B – Paramecium, C – Agaricus
A – Euglena, B – Paramecium, C – Aspergillus
Choose the correct statements (i v) regarding mycoplasma
(i) Mycoplasma has no cell wall.
(ii) Mycoplasma is the smallest living organism.
(iii) Mycoplasma cannot survive without O2.
(iv) Mycoplasma are pathogenic in animals and plants.
(v) A sort of sexual reproduction occurs in bacterium by adopting a primitive DNA transfer from one bacterium to the other.
Only (iii)
(i), (iii) and (v)
(i), (ii), (iv), and (v)
All of the above
Which of the following processes involved in the reproduction of protists ?
Binary fission and budding
Cell fusion and zygote formation
Spore formation and cyst formation
All of the above
Match the type of protozoans given in column-I with their examples given in column-II and choose the correct option.
| Column-I | Column-II |
|---|---|
| (Type of Protozoans) | (Examples) |
| A. Amoeboid protozoans | I. Paramecium |
| B. Ciliated protozoans | II. Plasmodium |
| C. Flagellated protozoans | III. Amoeba |
| D. Sporozoans | IV. Trypanosoma |
A I; B III; C IV; D II
A III; B I; C II; D IV
A III; B I; C IV; D II
A III; B IV; C I; D II
The given figure shows the structure of filamentous blue green algae, Nostoc with a structure marked as X. Select the option which shows the correct identification of the X with its feature.
Spores - Reproduction
Heterocysts - Nitrogen fixation
Pellicle - Recycling of nutrition
Mucilaginous sheath - Photosynthesis
Which of the following group of kingdom protista is being described by the statements given below ?
(i) This group includes diatoms and golden algae.
(ii) They are microscopic and float passively in water currents (plankton).
(iii) Most of them are photosynthetic.
(iv) They have deposits in their habitat; this accumulation over billion of years is referred to as diatomaceous earth.
Dinoflagellates
Chrysophytes
Euglenoids
Slime moulds
Ustilago causes plant diseases (called smuts) because
they parasitize on cereals.
they lack mycelium.
they develop sooty masses of spores.
their affected parts becomes completely black.
Which of the following statement is/ are correct for bacteria ?
They are the members of the kingdom monera.
They live in extreme habitats such as hot springs, deserts, snow and deep oceans.
They show the most extensive metabolic diversity.
All of the above