MP Board Class 12th Biology Important Questions Chapter 1 Reproduction in Organisms
Reproduction in Organisms Important Questions
Reproduction in Organisms Objective Type Questions
Choose the correct answers:
The endosperm in angiospermic plant is :
The function of tapetum innermost layer of the anther is :
In angiosperms, female gametophyte is represented by :
(d) Pollen grain
The endocarp of coconut is :
(d) Very hard and stony.
In Vallisneria, pollination takes place by :
Movement of male gamete towards archegonium in prothallus of fern is :
(d) Hygroscopic movement.
(d) Hygroscopic movement.
The process of double fertilization (triple fusion) was discovered by: (MP 2012)
Clonal cell line is obtained from :
(a) Tissue culture
(b) Tissue isolation
(c) Tissue mixture
(d) Tissue system.
(a) Tissue culture
Plants simillar to their parents can be obtained by :
(b) Stem cutting
(d) Both (a) and (b).
(d) Both (a) and (b).
A scion is grafted over stock. The quality of fruit depends on :
(c) Both (a) and (b)
(d) None of these.
The life span of a parrot is :
(a) One – two week
(b) 15 years
(c) 20 years
(d) 140 years.
(d) 140 years.
Stem cutting are commonly used for the propagation of :
If the organism is forged from male gamete without fertilization :
Fill in the blanks:
- Coconut water is the example of ………………
- ……………… is the fusion of male and female gamete.
- After fertilization of ovule ……………… is formed.
- ……………… is formed from ovary.
- The endosperm of gymnosperms is ………………
- The fusion of male and female gamete of the same flower of same plant is called ………………
- ……………… is called the end of reproductive cycle.
- The outer wall of pollen grain is called
- In Oxalis vegetative propagation takes place by ………………
- In Penicilliumasexual reproduction takes place by ………………
- Self polli – nation
Write the answer in one word/sentences:
- Name the process in which fruits are formed without fertilisation.
- Name the mode of reproduction in which new plants are formed from vegetative parts of the plants.
- Transfer of pollen grains from pollengrains to stigma of flower is called.
- Name the outer covering of seed.
- How many male gametes found in a pollen tube?
- Who provide nutrition to developing embryo?
- Write the name of an algae in which reproductive metshod occurs by zoospores.
- Give an example of vegetative propagation which is occurs by leaf.
- Name the animal which is reproduced by asexual reproduction.
- Split part of the body which is reproduce and developed in new plant is called.
- What we called the population of genetically similar organisms formed by asexual reproduction?
- Name the animal in which reproduction occurs by transverse binary fission.
- Vegetative propagation
Reproduction in Organisms Very Short Answer Type Questions
What is meant by life span?
The period from birth to the natural death of an organism is called life span.
Give definition of fertilization.
Fertilization is a process in which male and female gametes fused to form the zygote.
What is clone?
Morphologically and genetically similar individuals who are produced by single parent is called clone.
Give the name of an organism in which asexual reproduction occurs through conidia.
In which plant vegetative propagation occurs through rhizome?
In Ginger and Turmeric.
Give the name of an organism in which transverse binary fission occurs.
What is ageing?
When humans are not capable for reproduction is known as ageing.
Give two examples of hermaphrodite plants.
Cucurbita and Coconut are hermaphrodite plants.
Reproduction in Organisms Short Answer Type Questions
Name the types of reproduction occur in the living organisms.
Two types of reproduction occur in the living organisms:
- Asexual reproduction
- Sexual reproduction.
Which is a better mode of reproduction, sexual or asexual. Why?
Sexual mode of reproduction is better because it is biparental reproduction and introduces variation among offsprings and their parants due to crossing over and recombination during gamete formation by meiosis.
Why is the offspring formed by asexual reproduction referred to as clone ?
Answer: In sexual reproduction, the offspring is morphologically and genetically identi-cal to the parent and to each other. Hence, it is called clone.
Write three advantages of asexual reproduction.
Following are the three advantages of asexual reproduction:
- Large number of offsprings can be produced by single parent.
- Purity can be maintained.
- It helps in dispersal to far off places.
Offsprings formed due to sexual reproduction have better chances of survival. Why? Is this statement always true?
Offsprings formed due to sexual reproduction have better chance of survival because:
- The offspring consists of hybrid characters which may adapt better with the different environment.
- Genetic variations are introduced among the offsprings which increases the bio – logical tolerance.
- Sexual reproduction occurs in adverse condition in lower plant kingdom, so sexual spores survive in adverse condition.
Sexual reproduction may not always show better chances of survival because the off – spring may be inferior to the parents.
How does the progeny formed from asexual reproduction differ from those formed by sexual reproduction?
The progenies have similar genetic make up and are exact copies of their parents in asexual reproduction but the progenies have different genetic make up and different from each other and dissimilar to the parent in sexual reproduction.
Variation is absent in asexual reproduction but it is a common phenomenon of sexual reproduction. In asexual reproduction, variation may occur due to mutation whereas variation occurs due to mutation, crossing over and recombination in sexual reproduction.
Distinguish between asexual and sexual reproduction. Why is vegetative reproduction also considered as a type of asexual reproduction?
Differences between Asexual and Sexual reproduction:
- In this type of reproduction only one parent is required.
- Whole body or a single cell acts as reproductive unit.
- Offsprings remain pure, i.e., alike their parents.
- It occurs by mitosis cell division.
- Variation does not occur.
- In this type of reproduction two parents of different sexes are required.
- Reproductive units are called as gametes which are produced by specific tissues.
- Offsprings differ from their parents.
- Gametes are formed by meiosis cell division and zygote develops by mitosis cell division.
- Variation occurs.
Vegetative reproduction is considered as a type of asexual reproduction because:
- It is uniparental reproduction.
- There is no involvement of gametes or sex cells.
- Cell division and no reduetional division take place.
- Vegetative propagules are somatic cells.
What is vegetative propagation? Give two suitable examples.
In plants, the vegetative propagules (runner, rhizome, sucker, etc.) are capable, of producing new offsprings by the process called vegetative propagation. As the formation of these vegetative propagules does not involve both the parents, the process involved is asexual.
- Adventitious buds in the notches along the leaf margins of bryophyllum grow to form new plants.
- Potato tuber having buds when grown, develops into a new plant.
- Juvenile phase
- Reproductive phase
- Senescent phase.
1. Juvenile phase:
It is the pre – reproductive in which all organisms require a certain growth and maturity in the life before reproducing sexually.
2. Reproductive phase:
Reproductive phase is the phase in the life cycle, where an organism possesses all the capacity and potential to reproduce sexually. It is the end of juvenile phase or vegetative phase.
3. Senescent phase:
It is the post reproductive phase in the life cycle where an organism slowly looses the rate of metabolism, reproductive potential and show deterioration of the physiological activity of the body.
Higher organisms have resorted to sexual reproduction inspite of its complexity.Why?
Higher organisms have resorted to sexual reproduction to:
- Get over the unfavourable conditions.
- Restore high gene pool in a population.
- Restore vigour and vitality of the race.
- Get proper parental care.
- Introduce variations to enable better adaptive capacity.
Explain, why meiosis and gametogenesis are always interlinked.
Gametogenesis (formation of male and female gametes) is associated with reduction in chromosome number. Thus, the gamete formed contains half chromosome set of the parental cell. So, gametogenesis is interlinked with meiosis because in meiosis reduction of chromosome number from diploid set (2n) to haploid set (n) takes place.
Identify each part in a flowering plant and write whether it is haploid (n) or diploid (2n).
Define external fertilization, mention its disadvantages.
The fusion of compatible gametes (male and female) outside the body of an organism is called external fertilization, example in Frog.
Disadvantages of external fertilization:
- It requires a medium for fusion of gametes.
- The young ones are often exposed to the predators.
- After fertilization, offsprings are produced large in number but no parental care is provided.
Differentiate between a zoospore and zygote.
Differences between Zoospores and Zygote:
- These are endogenously, asexually produced, unicellular, naked and motile spores having one or two flagella.
- It may be haploid or diploid.
- Zoospores takes part in dispersal.
- Zygote is a diploid cell formed by fusion of male and female gametes.
- It is always diploid.
- Zygote does not have significant role in dispersal.
Differentiate between gametogenesis and embryogenesis.
Differences between Gametogenesis and Embryogenesis:
- It is the formation of gametes from me – iocytes.
- This is a pre – fertilization event.
- It occurs inside reproductive organs.
- It produces haploid gamete.
- The cell division during gametogenesis is meiotic in diploid organisms.
- It is the formation of embryo from zyg – ote cell.
- This is a post fertilization event.
- It occurs outside or inside the female body.
- It gives rise to diploid embryo.
- The cell division during embryogenesis is mitotic in diploid organisms.
What is gootee? How it is prepared?
Gootee or Air layering:
It is a modified form of layering in which the cut or injured branch is not buried in the soil but is bound with mud and rags, etc. which is kept moist with the help of water kept in an earthen pot. The roots develop at this portion within a period of about a month or two. Now, the branch is cut and separated from the parent plant and planted in the soil. This method is applied for the vegetative, propagation of Lemon, Orange, Litchi, Guava, Lokat, etc.
What do you understand by grafting? Write down the method of grafting.
Vegetative reproduction or vegetative propagation is the process of multiplication in which a portion or fragment of the plant body functions as propagate and develops into new individual. Grafting is a type of artificial vegetative propagation.
Importance of vegetative propagation:
- Pure variety can be produced
- It increases production.
This is a very significant method and is extensively used for growing Roses and Mangoes. Grafting is making a twig or bud of one plant grow on the trunk and root system of another. In this process a detached portion of one plant is inserted into the stem or root system of another plant. The former is called scion (short piece of detached shoot containing several dormant buds) and the latter stock (lower portion of the plant which is fixed to the soil by its root system).
Grafting is done in such a way that the cambium tissue of both scion and stock comes in contact and forms a cambium layer common to both. Consequently the scion and the stock grow together and the scion becomes part of the plant into which it is grafted.