Tag: the life cycle of plants

Questions Related to the life cycle of plants

Which one of the following mutations is not hereditary?

botany modes of reproduction why do plants reproduce? reproduction and variation the life cycle of plants

  1. Gametic

  2. Zygotic

  3. Somatic

  4. Genetic

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Correct Option: C
Explanation:

Mutations are the permanent changes in the nucleotide sequence of the genome of an individual. These can occur during replication of DNA or its exposure with radiations or carcinogens, etc.

Somatic mutations occur in somatic cells, also known as non-reproductive cells. The genes in these cells are non-heritable and hence any mutations the will not be passed to next generations. The only mutations that are inherited if they occur in gametes (eggs and sperm). Such mutations that occur in gametes are also called germ-line mutations.
So, the correct option is 'Somatic'.

Number of spermatozoa, a single primary spermatocyte ultimately produced in spermatogenesis is

botany modes of reproduction why do plants reproduce? reproduction and variation the life cycle of plants

  1. 1

  2. 2

  3. 4

  4. 8

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Correct Option: C
Explanation:
The immature male germ cells (spermatogonia) produce sperms by spermatogenesis that begins at puberty. The spermatogonia present on the inside wall of seminiferous tubules multiply by mitotic division and increase in numbers. Each spermatogonium is diploid and contains 46 chromosomes. Some of the spermatogonia called primary spermatocytes periodically undergo meiosis. A primary spermatocyte completes the first meiotic division (reduction division) leading to the formation of two equal, haploid cells called secondary spermatocytes, which have only 23 chromosomes each. The secondary spermatocytes undergo the second meiotic division to produce four equal, haploid spermatids. 

The life span of a dog is 

botany modes of reproduction why do plants reproduce? reproduction and variation the life cycle of plants

  1. 16 - 18 days

  2. 16 - 18 weeks

  3. 16 - 18 months

  4. 16 - 18 years

Show answer
Correct Option: D
Explanation:

The life span of dog is 16 - 18 years. Life expectancy in dogs can be affected by many factors including genetic disease, diet, and exercise, similar to humans. Life expectancy usually varies within a range. For example, a Beagle (average life expectancy 13.3 years) usually lives to around 12–15 years, and a Scottish Terrier (average life expectancy 12 years) usually lives to around 10–16 years.

So, the correct answer is '16 - 18 years'

A natural method of birth control assumes that sperms live for three days after intercourse, ovulation occurs between days $13-15$ of the menstrual cycle and released ova live for $36$ hours.
On which day of the cycle should intercourse not result in pregnancy?

botany modes of reproduction why do plants reproduce? reproduction and variation the life cycle of plants

  1. Day $7$

  2. Day $10$

  3. Day $12$

  4. Day $16$

Show answer
Correct Option: A
Explanation:

A woman is fertile, on average, between the ages of $12$ to $15$. During these fertile years, a recurring process - known as the menstrual cycle - takes place each month. This involves the lining of the uterus preparing for pregnancy. If pregnancy does not occur, the lining breaks down and the woman has a period. This is also known as menstruation. During this period which is generally from day $1$ to the day $7$ of the cycle, the intercourse does not result in pregnancy.

Which statement describes human cells formed by meiosis?

botany modes of reproduction why do plants reproduce? reproduction and variation the life cycle of plants

  1. They are genetically identical and they become gametes.

  2. They are genetically identical and they become tissues.

  3. They are not genetically identical and they become gametes.

  4. They are not genetically identical and they become tissues.

Show answer
Correct Option: C
Explanation:

In women, both sex chromosomes are the same and are therefore called as XX. In males, they are different and called as XY. When sperm and eggs (ova) are made during meiosis they separate to form different gametes. As women have XX, their eggs always carry the X chromosomes. As males have XY, approximately half their sperm carry the X chromosome while the remainder carries the Y chromosome.

Which of the following is associated with reproduction?

botany modes of reproduction why do plants reproduce? reproduction and variation the life cycle of plants

  1. Parthenogenesis

  2. Fertilization

  3. STDs

  4. All of the above

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Correct Option: D
Explanation:
Parthenogenesis is a natural form of asexual reproduction in which growth and development of embryos occur without fertilization.
Fertilization is the action or process of fertilizing an egg or a female animal or plant, involving the fusion of male and female gametes to form a zygote.
STDs stands for sexually transmitted disease. It is the infection transmitted through sexual contact, caused by bacteria, viruses or parasites.
So, the correct answer is option D.

Reproduction is a .......... process of life.

botany modes of reproduction why do plants reproduce? reproduction and variation the life cycle of plants

  1. Structural

  2. Metabolic

  3. Fundamental

  4. None of the above

Show answer
Correct Option: C
Explanation:

Reproduction is the process of continuation of a species. It is a mode of production of new organisms, called offsprings, from their parents. Each organism exists due to reproduction. With every new offspring, genetic variations are passed from the parents, that help the offspring survive better in the environment. Such variations and adaptations contribute to a species sustaining life for a longer duration.

Which of the following process of maintains the existence of the species on the earth?

botany modes of reproduction why do plants reproduce? reproduction and variation the life cycle of plants

  1. Metabolism

  2. Reproduction

  3. Adaptation

  4. None of the above

Show answer
Correct Option: B
Explanation:
Metabolism is a term that is used to describe all chemical reactions involved in maintaining the living state of the cells and the organism.
Reproduction is a biological process by which new individual organisms or offspring are produced from their parents. It is a fundamental feature of all known life and each individual organism exists as the result of reproduction.
Adaptation is the process of change by which an organism or species becomes better suited to its environment.
So, the correct answer is option B.

In certain plants viable pollen is formed but it cannot pollinate owing to nonrupture of anther wall. This condition is referred to as _____________.

botany modes of reproduction why do plants reproduce? reproduction and variation the life cycle of plants

  1. Cytoplasm sterility

  2. Functional sterility

  3. Genic sterility

  4. Genetic and cytoplasmic sterility

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Correct Option: A

Which one of the following plant species reproduces by apomixes?

botany modes of reproduction why do plants reproduce? reproduction and variation the life cycle of plants

  1. Nicotiana tabacum

  2. Pavonia Zeytanica

  3. Poa pratensis

  4. Eclipta alba

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Correct Option: A