Tag: botany

Questions Related to botany

Siphonogamy occurs in

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. Gymnosperms

  2. Monocots

  3. Dicots

  4. All of the above

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Correct Option: D

Growth of the pollen tube is

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. Apical

  2. Intercalary

  3. Basal

  4. Intermittent

Show answer
Correct Option: A
Explanation:

In sexual reproduction of plants, the sperm is transferred to the egg through a long, polarized tube of a pollen cell called as the pollen tube. The growth of the pollen tube is apical. It grows at its tip at very rapid rate. The rapid growth is due to a highly polarized fusion of apical vesicles. These transport cell wall components to the growing tip via cytoplasmic streaming and are incorporated into a zone of elongation in the apical region of the pollen tube. Hence, the pollen tube extends its length by apical growth in a relatively small region.

Thus, the correct answer is option A.

Choose the correct answers from the alternatives given.
Entrance of a pollen tube into an ovule through the micropyle is called

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. porogamy

  2. mesogamy

  3. chalazogamy

  4. apogamy

Show answer
Correct Option: A
Explanation:

After reaching ovary, the pollen tube enters the ovule. When the pollen tube enters the ovule through micropyle, it is called porogamy. It is the most common type. e.g., Lily. 

So, the correct option is, 'porogamy'.

Entry of pollen tube in the ovule through integument is called

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. Chalazogamy

  2. Basigamy

  3. Mesogamy

  4. Porogamy

Show answer
Correct Option: C
Explanation:
The entry of pollen tube in the ovule through integument is commonly known as mesogamy. It is commonly seen in plants like Cucurbita, Populus, etc.
So, the correct answer is 'Mesogamy'.

The apical growing region of pollen tube called

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. Growing zone

  2. Cap block

  3. Non-vacuolate region

  4. Organelle region

Show answer
Correct Option: B
Explanation:

Apical zone of pollen tube contains abundant vesicles but lacks cell organelles. It is hemisphere in shape and transparent in nature. This transparent apical growing region of pollen tube is called as cap block. It exists only until the tube is growing. It disappears as soon as the growth ceases. 

Thus, the correct answer is option B. 

The functional part of the pollen tube is separate from the rest by

botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

  1. Vacuoles

  2. Callose plugs

  3. Septa

  4. Both B and C

Show answer
Correct Option: B
Explanation:

Callose is a beta-1,3-glucan. It is the major component of the pollen tube cell wall. It is also deposited within the cytoplasm as distinct callose grains. This leads to the formation of callose plugs. Callose plugs separate the living, growing and functional part of the pollen tube in the tip from the remaining degenerating part.

Thus, the correct answer is option B.

Which one of the following is not one of the three aspects studied in biogeochemical cycling?

botany energy flow in an ecosystem biogeochemical cycle nutrient cycles species, communities and ecosystems

  1. The nature and size of natural reservoir

  2. The rate of movement between reservoirs

  3. Interaction between different biogeochemical cycles

  4. Creation of their own biogeochemical cycles by new species

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Correct Option: D
Explanation:
The cyclic movement of the elements from the abiotic system to the biotic system and back again is the biogeochemical cycle. These chemicals form the compounds of food, so these are also known as nutrient cycles.
Some of the important biogeochemical cycles are carbon cycle, Oxygen cycle nitrogen cycle, Phosphorus cycle.
Following aspect are studied in biogeochemical cycling-
The nature and size of the natural reservoir
The rate of movement between reservoirs
The interaction between different biogeochemical cycles
The correct option is the 'creation of their own biogeochemical cycles by new species'

The reservoir for the gaseous type of biogeochemical cycle exists in.

botany energy flow in an ecosystem biogeochemical cycle nutrient cycles species, communities and ecosystems

  1. Stratosphere

  2. Atmosphere

  3. Ionosphere

  4. Lithosphere

Show answer
Correct Option: B
Explanation:

The reservoir for gaseous type of nutrient cycles, e.g., nitrogen, carbon cycle exist in the atmosphere.

Which of the following are the examples of biogeochemical cycle?

botany energy flow in an ecosystem biogeochemical cycle nutrient cycles species, communities and ecosystems

  1. Nitrogen cycle

  2. Krebs cycle

  3. Electron cycle

  4. All of the above

Show answer
Correct Option: A
Explanation:

A biogeochemical cycle involves biological, geological and chemical factors. The circulation of chemical nutrients like carbon, oxygen, nitrogen, phosphorus, calcium, and water, etc. between biotic and abiotic components of the biosphere is known as a biogeochemical cycle.
So, the correct option is option A.

The reservoir pool for gaseous cycles of matter is

botany energy flow in an ecosystem biogeochemical cycle nutrient cycles species, communities and ecosystems

  1. Atmosphere

  2. Hydrosphere

  3. Both (A) and (B)

  4. Lithosphere

Show answer
Correct Option: A
Explanation:

Biogeochemical cycles involves the exchange of minerals between abiotic and biotic components of the biosphere. It is mainly of three types hydrological, gaseous and sedimentary.
Gaseous cycle involves the transportation of matter through the atmosphere. Some examples of the gaseous cycle are carbon cycle, nitrogen cycle, oxygen cycle.
So, the correct answer is option A.