Tag: botany

Questions Related to botany

The internal source of $C{ O } _{ 2 }$ in CAM plants is

botany photosynthesis cam cycle cam plants photosynthetic cycle

  1. Oxalo-acetic acid

  2. Malic acid

  3. RUBP

  4. PEPA

Show answer
Correct Option: A
Explanation:

Crassulacean acid metabolism, also known as CAM photosynthesis, is a carbon fixation pathway that evolved in some plants as an adaptation to arid conditions. In a plant using full CAM, the stomata in the leaves remain shut during the day to reduce evapotranspiration, but open at night to collect carbon dioxide (CO$ _2$). So the correct option is 'Oxalo-acetic acid'.

In which of the following respects the photosynthetic adaptations of $C _4$ plants and CAM plants are similar?

botany photosynthesis cam cycle cam plants photosynthetic cycle

  1. In both cases, stomata normally close during the day

  2. Both types of plants make their sugar without the Calvin cycle

  3. In both cases, an enzyme other than rubisco carries out the first step in carbon fixation

  4. Neither $C _4$ plants nor CAM plants have grana in their chloroplasts

Show answer
Correct Option: C
Explanation:

$C _4$ and CAM  plants are plants that use certain special compounds to gather carbon dioxide (CO 2 ) during photosynthesis. Exploitation of dry and arid habitats required adaptations in the form of $C _4$ and CAM photosynthesis, which independently evolved many times during periods of low atmospheric $CO _2$ levels carried out by carried out by a non-rubisco enzyme, PEP carboxylase, that has no tendency to bind $O _2$.

So, the correct option is, 'In both cases, an enzyme other than rubisco carries out the first step in carbon fixation'.

In kranz anatomy, the bundle sheath cells have

botany photosynthesis cam cycle cam plants photosynthetic cycle

  1. thin walls, many intercellular spaces and no chloroplasts

  2. thick walls, no intercellular spaces and large number of chloroplasts

  3. thin walls, no intercellular spaces and several chloroplasts

  4. thick walls, many intercellular spaces and few chloroplasts.

Show answer
Correct Option: B
Explanation:
In Kranz anatomy, the bundle sheath cells are characterized by having a large number of agranal chloroplasts, thick walls impervious to gaseous exchange and no intercellular spaces.
Thus, the correct answer is 'thick walls, no intercellular spaces and large number of chloroplasts.'

Both autogamy and geitonogamy are prevented in 

botany asexual and sexual reproduction in plants types of pollination cross pollination pollination and its types

  1. Papaya

  2. Cucumber

  3. Castor

  4. Maize

Show answer
Correct Option: A
Explanation:

Papaya plant is a dioecious plant. It prevents both autogamy and geitonogamy, which is a method of self pollination.

Pollen grains do not germinate on the stigma of the same flower. The phenomenon is

botany pollination and fertilization types of pollination cross pollination pollination and its types

  1. Prepotency

  2. Self sterility

  3. Dicliny

  4. Dichogamy

Show answer
Correct Option: B
Explanation:
When a pistil having functional female gametes fails to set seeds with viable and fertile pollen, which can bring about fertilisation in another pistil, the pistil and pollen are said to be incompatible and this is known as incompatibility. 
When the sexual incompatibility is between individuals of different species, it is interspecific.
When the sexual incompatibility is between individuals of same species, it is intraspecific. This intraspecific incompatibility is also called as self-incompatibility which may include many reasons like pollen fail to germinate on the surface of the stigma of the same flower, which is also known as self-sterility.
So, the correct answer is B.

Two species live in the same locale but each one reproduces at the different time of the year & both do not attempt to mate each other. This can be considered as an example of

botany pollination and fertilization types of pollination cross pollination pollination and its types

  1. Gamete isolation

  2. Mechanical isolation

  3. Behavioral isolation

  4. Hybrid sterility

Show answer
Correct Option: C
Explanation:

The species of birds and animals shows different types of isolation. The organisms which are located in the same habitat or geographical area but do not mate with each other. This type of isolation is known as the behavioral isolation in which different species have a different type of behavior with respect to reproduction. This prevents the interbreeding of the different species. 

Thus, the correct answer is option C. 

Transfer of pollen between two plants is 

botany pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. Cross pollination

  2. Self pollination

  3. Pollen transfer

  4. None of the above

Show answer
Correct Option: A
Explanation:

The transfer of pollen from an anther of a flower of one plant to a stigma of a flower of another plant of the same species by the action of wind, insects etc is known as cross pollination. 

Name the phenomenon of two flowers, one having long stamens and short styles, and other having short stamens and long style

botany pollination and fertilization types of pollination cross pollination pollination and its types

  1. Allogamous device

  2. Heterostyly

  3. Dicliny

  4. Herkogamy

Show answer
Correct Option: B
Explanation:
Heterostyly is the presence of 2 or 3 types of flowers within the same plant and such flowers differ in the length of style and stamens. Example, Primula which shows distyly.
It has two types of flowers:
1. Pin eyed flowers: These have long styles with short stamens.
2. Thrum eyed flowers: These have a short style and long stamens.
So, the correct answer is B.

Find out correct statement:-

botany pollination and fertilization types of pollination cross pollination pollination and its types

  1. Clonal selection is applicable to cross pollinated crops

  2. Inbreeding depression is loss of vigour due to inbreeding

  3. Dr. M.s swaminathan is responsible for revolution in india.

  4. plant tissue culture technique is not based on totipotency

Show answer
Correct Option: A

Cross-pollination is preferred over self-pollination because it?

botany pollination and fertilization types of pollination cross pollination pollination and its types

  1. Produces better offspring

  2. Forms new varieties

  3. Induces parthenogenesis

  4. Is economical

Show answer
Correct Option: B
Explanation:
  • Cross-pollination can be defined as the transfer of pollen grains from the male reproductive organ (an anther or a male cone) of one plant to the female reproductive organ (a stigma or a female cone) of another plant. 
  • Insects and wind act as the agents of cross-pollination.
  • Cross-pollination helps to produce varieties in species by recombinant genes while self-pollination maintains homozygosity. 
  • So the correct option is 'forms new varieties'.