In angiosperms, a mature male gametophyte is derived from a pollen mother cell by
three mitotic divisions.
one meiotic and two mitotic divisions.
two meiotic divisions.
a single meiotic division.
Correct Answer :
B. one meiotic and two mitotic divisions.
In angiosperms, a mature male gametophyte is derived from a pollen mother cell by one meotic and two mitotic divisions. In the pollen sac (microsporangium) of the anther haploid microspores are formed by meiosis. Mitosis then follows to produce a two-celled pollen grain with a small generative cell and a large vegetative cell. This generative cell will undergo further mitosis to form two male gametes (nuclei). The pollen tube grows through a spore in the pollen grain, with the tube (vegetative) nucleus at its tips and the male nuclei behind.
Related Questions
What is the number and position of insertions of flagella in rhodopyceae class of algae ?
2 - 8, equal, apical
2, unequal, lateral
2 - 6, equal, lateral
Absent
Select the correct match of the feature present in column I with its respective terms given in column II.
| Column-I | Column-II |
|---|---|
| A. Presence of tap roots | (i) Bryophyte and coralloid roots |
| B. The synergids and | (ii) Pteridophytes antipodal cells degenerates after fertilization |
| C. The food is stored as | (iii) Red algae floridean starch which is very similar to amylopectin and glycogen in structure |
| D. Presence of sporophyte | (iv) Angiosperms which is not free living but attached to the photosynthetic gametophytes and derives nourishment from it |
| E. Members of this group | (v) Gymnosperms are used for medicinal purposes, as soil binders and frequently grown as ornamentals |
A-i B-ii C-iii D-iv E-v
A-iii B-v C-ii D-iv E-i
A-iii B-i C-v D-ii E-iv
A-v B-iv C-iii D-i E-ii
Classification of plants proposed by Carolus Linnaeus was artificial because it was based on
only a few morphological characters.
evolutionary tendencies which are diverse.
anatomical characters which are adaptive in nature.
physiological traits alongwith morphological characters.
Laminaria (Kelp) and Fucus (Rock weed) are examples of
green algae
brown algae
red algae
golden brown algae
Angiosperms have dominated the land flora primarily because of their
power of adaptability in diverse habitat.
property of producing large number of seeds.
nature of self pollination.
domestication of man.
Match column-I with column-II and choose the correct option.
| Column-I | Column-II |
|---|---|
| A. Phaeophyceae | I. Have an elaborate mechanism of spore dispersal |
| B. Rhodophyceae | II. first terrestrial plant with vascular tissue-phloem and xylem |
| C. Mosses | III. Asexual reproduction by biflagellate zoosposes |
| D. Pteridophytes | IV. Polysiphonia, Porphyra, Gracilaria |
A III; B IV; C I; D II
A IV; B III; C I; D II
A IV; B III; C II; D I
A IV; B I; C III; D II
Statement 1: Members of phaeophyceae vary in colour from olive green to various shades of brown.
Statement 2: Phaeophyceae possess chlorophyll a, c, carotenoids and xanthophylls.
Both statements -1 and statement - 2 are true and statement - 2 is the correct explanation of statement - 1.
Both statements -1 and statement - 2 are true but statement - 2 is not the correct explanation of statement - 1.
Statement -1 is true and statement - 2 is false.
Statement -1 is false and statement - 2 is true.
In angiosperms, a mature male gametophyte is derived from a pollen mother cell by
three mitotic divisions.
one meiotic and two mitotic divisions.
two meiotic divisions.
a single meiotic division.
Match the column I with column II and choose the option which shows its correct combination.
| Column-I | Column-II |
|---|---|
| (Pattern of life cycle in plant) | (Examples) |
| A. Haplontic | I. Bryophytes, Pteridophytes, life cycle Ectocarpus, Polysiphonia, Kelps |
| B. Diplontic | II. Seed bearing plants life cycle (Gymnosperm and Angiosperm), Fucus |
| C. Haplo-diplontic | III. Many algae (Volvox, life cycle Spirogyra) and some species of Chlamydomonas |
A III; B II; C I
A I; B II; C III
A II; B I; C III
A III; B I; C II
Which of the following branch of science is being described by the given statements ?
(i) It can easily done by using computers based on all observable characters.
(ii) Numbers and codes are assigned to all the characters and the data are then processed.
(iii) Each character is given equal weightage and at the same time hundred of characters can be considered.
Cytotaxonomy
Numerical taxonomy
Chemotaxonomy
??-taxonomy
You are given an unknown plant to study in the laboratory. You find that it has chlorophyll, no xylem. Its multicellullar sex organs are enclosed in a layer of jacket cells. Its gametophyte stage is free living. The plant probabily belongs to
chlorophyceae
bryophyte
pteridophyte
gymnosperm
A bryophyte differs from pteridophytes in having
archegonia.
lack of vascular tissue.
swimming antherozoids.
independent gametophytes.
What is common in all the three, Funaria, Dryopteris and Ginkgo?
Independent sporophyte
Presence of archegonia
Well developed vascular tissues
Independent gametophyte
Which of the following group of plant is being described by the given statements ?
(i) They are plants in which the ovules are not enclosed by any ovary wall and remain exposed before and after fertilization.
(ii) The giant red wood tree Sequoia is one of the tallest tree species of the group.
(iii) The roots are generally tap roots.
(iv) They are heterosporous and they produce haploid microspores and megaspores.
Algae
Bryophytes
Gymnosperms
Pteridophytes
The heterosporous pteridophyte belonging to the class lycopsida is
Selaginella
Psilotum
Equisetum
Pteris
Which of the following statement is incorrect ?
Double fertilization is unique to gymnosperms and monocotyledons.
Sequoia, a gymnosperm, is one of the tallest tree species.
Phaeophyceae members possess chlorophyll a, c, carotenoids and xanthophylls.
Moss is a gametophyte which consists of two stages namely, protonemal stage and leafy stage.
If you are asked to classify the various algae into distinct groups then which of the following characters you should choose for the classification ?
Nature of habitat
Structural organization of thallus
Chemical composition of the cell wall
Types of pigments present in the cell.
Consider the following statements regarding gymnosperms and choose the correct option.
(i) In gymnosperms, the male and female gametophytes have an independent existence.
(ii) The multicellular female gametophyte is retained within the megasporangium.
(iii) The gymnosperms are heterosporous. Of these statements
(i) and (ii) are correct but (iii) is incorrect
(i) and (iii) are correct but (ii) is incorrect
(ii) and (iii) are incorrect but (i) is correct
(ii) and (iii) are correct but (i) is incorrect
Which one of the following statement concerning the algae is incorrect ?
Most algae are photosynthetic.
Algae can be classified according to their pigments.
All algae are filamentous.
Spirogyra does not produce zoospores.
Fruits are not formed in gymnosperms because of
absence of pollination.
absence of seed.
absence of fertilization.
absence of ovary.
Algin, carrageen and proteins are obtained from
red algae, brown algae, green algae respectively.
brown algae, red algae, green algae respectively.
red algae, green algae, brown algae respectively.
green algae, brown algae, red algae respectively.
A student was given a sample to observe under the microscope. He observed and found that the sample is the most common type of spore involved in asexual reproduction in algae. Identify the spore.
Zoospore
Endospore
Hypnospore
None of the above
What is the similarity between gymnosperms and angiosperms?
Phloem of both have companian cells.
Endosperm is formed before fertilization in both.
Origin of ovule and seed is similar in both.
Both have leaves, stem and roots.
A research student collected certain alga and found that its cells contained both chlorophyll a and chlorophyll d as well as phycoerythrin on the basis of his observation the students conclude that the alga belongs to
rhodophyceae
bacillariophyceae
chlorophyceae
phaeophyceae
_______ represent the reproductive organs amongst gymnosperms.
Prothallus
Capsules
Setae
Cones
Protonema and leafy stage are the predominant stage of the life cycle of
moss
dicots
liverwort
gymnosperm
Match the column-I with column-II and choose the correct option.
| Column-I | Column-II |
|---|---|
| (System of classification) | (Characteristics) |
| A. Artificial system | I. Based on few morphological of classification characters |
| B. Natural system | II. Based on evolutionary of classification relationships between the various organisms |
| C. Phylogenetic | III. Based on natural affinities system of among the organisms and classification consider external as well as internal features. |
A II; B I; C III
A I; B III; C II
A III; B II; C I
A I; B II; C III
Mosses are of great ecological importance because of
its contribution to prevent soil erosion.
its contribution in ecological succession.
its capability to remove CO from the atmosphere.
both (a) and (b)
Pyrenoids in green algal cells are related to
starch formation
protein storage
general metabolism
enzyme secretion
Which of the following statement(s) is/are correct?
(i) Green algae are the members of chlorophyceae.
(ii) Brown algae are found primarily in marine habitates
(iii) Some red algae are found in fresh water, mostly occur in salt water, some are in brackish water.
(iv) The food in red algae is stosed as floridean starch.
(v) Red alga may occur in both well-lighted regions close to water-surface and also at great depths in oceans where light penetration is little.
(i) and (v) only
(ii), (iii) and (iv) only
All of the above
None of the above