MULTIPLE CHOICE QUESTIONS

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CBSE CLASS XII BIOLOGY

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With reference to the following schematic diagram of representation of various events of menstrual cycle, choose the correct description of the events of proliferative phase of menstrual cycle. *

1 point

Gradual increase in secretion of gonadotropins -LH and FSH, Transformation of primary follicles to graafian follicle and proliferation of endometrium

Occur menstrual flow for 3-5 days

Secretion of LH and FSH attain a peak level, Rupture of Graafian follicle and occur ovulation

Graafian follicle transform as the corpus luteum, Secretion of large amounts of progesterone by corpus luteum.

There is no natural death in single celled organisms like Amoeba and bacteria because *

1 point

they cannot reproduce sexually

they reproduce by binary fission

parental body is distributed among the offspring

they are microscopic

Class *

XII Kausani

XI Kausani

Required

Strobilanthus Kunthiana (Neelakurinji) blossom *

1 point

only once in 50-100 years

only once in 12 years

Many times in 50-100 years

Twice in 50-100 years

Which of the following is a post-fertilisation event in flowering plants? *

1 point

Transfer of pollen grains

Embryo development

Formation of flower

Formation of pollen grains

Entomophily is carried by *

1 point

Birds

Insects

Bats

Wind

Other:

Predators feeds on the ova and offspring produced by *

1 point

Viviparous animals

Oviparous animals

Bisexual

Unisexual

Identify the correct steps of sexual reproduction in plants *

1 point

Sporogenesis → Pollination → Embryogenesis → Double fertilisation → Development of fruit

Sporogenesis → Pollination → Double fertilisation → Embryogenesis → Development of fruit

Sporogenesis → Embryogenesis → Pollination → Double fertilisation → Development of fruit

Pollination → Sporogenesis → Double fertilisation → Embryogenesis → Development of fruit

Two major modes of reproduction in living organisms are *

1 point

Binary fission and multiple fission

Production of female gametes and male gametes

Sexual and asexual modes of reproduction

None of these

About 300 million spermatozoa may be present in a human male ejaculation at one time. Calculate how many spermatocytes will be involved to produce this number of spermatozoa. *

1 point

300 million/1= million

300 million/4 = 75 million

300 million/2=150 million

300 million x 2/4=37.5 million

Vegetative propagules in potato and bryophyllum are *

1 point

Eyes and Leaf buds respectively

Eyes and rhizome respectively

Eyes and bulbil respectively

Eyes and offset respectively

Name *

Bamboo flowers *

1 point

only once in 50-100 years

only once in 12 years

Many times in 50-100 years

Twice in 50-100 years

Term for the existence of morphologically similar gametes in both male and female gametes is *

1 point

Homogametes (isogametes)

Heterogametes (anisogametes)

Homogamy

None of these

Pre-fertilisation events include *

1 point

Internal fertilisation and external fertilisation

Formation of zygote and embryogenesis

Gametogenesis and gamete transfer

Meiosis to form gametes

Offspring formed by sexual reproduction exhibit more variation than those formed by asexual reproduction because *

1 point

sexual reproduction is a lengthy process

gametes of parents have qualitatively different genetic composition

genetic material comes from parents of two different species

a greater amount of DNA is involved in sexual reproduction

In the embryos of a typical dicot and a grass, true homologous structures are: *

1 point

Coleorhiza and coleoptile

Coleoptile and scutellum

Cotyledons and scutellum

Hypocotyl and radicle.

Ploidy of chromosomes in haploid and diploid organisms are *

1 point

2n and n respectively

3n and 2n respectively

2n and 2n respectively

n and 2n respectively

Choose the correct labels for E for the following diagrammatic representation of enlarged view of one microsporangium showing all layers. Which among these will form pollen grains through microsporogenesis? *

1 point

Pollen is formed from

Middle layer

Megaspore mother cell

Tapetum

Endothecium

Epidermis

Urethral meatus refers to the *

1 point

Urinogenital duct

Opening of vas deferens into urethra

External opening of the urinogenital duct

Muscles surrounding the urinogenial duct

Inbreeding depression can be explained as *

Choose the correct description for the inbreeding depression and outbreeding devices

1 point

Inbreeding depression

Outbreeding devices

Reduction in fertility and productivity, characterised by reduced pollen production and decreased in quality and quality of seeds

Pollination within the same plant

Pollination between two different plants of same species

Mechanisms to discourage self pollination and to encourage cross-pollination (for more genetic diversity)

Emasculation technique used during artificial hybridisation can be explained as *

1 point

Technique to improve crop variety by artificial hybridisation which can be intervarietal, interspecific and intergeneric.

Crossing between genetically dissimilar plants to produce a superior hybrid with superior genetic combination.

Covering of emasculated flowers with a bag of suitable size, generally made up of butter paper, to prevent contamination of its stigma with unwanted pollen.

Removal of immature anthers from the bisexual flower bud before the anther dehisces using forceps.

How do scientists store pollen grains for future use? *

Tick the most appropriate answer for the question

1 point

Answer

Sporopollenin is the most resistant organic material known by virtue of which pollen grains are well preserved as fossils.

Pollen grains are stored for many years in liquid nitrogen (-196 ˚C).

Scientists can store pollen grains in pollen banks.

Microsporocyte is most resistant organic material known by virtue of which pollen grains are well preserved as fossils.

Non-primate mammals like cows and dogs exhibit *

1 point

Cell cycle

Oestrous cycle

Menstrual cycle

Sexual cycle

Number of chromosomes in male gametes of butterfly having a total of 380 chromosomes is *

1 point

190

570

Either 190 or 95

Development of unfertilised ovum into a new individual is called *

1 point

Parthenogenesis

Embryogenesis

Gametogenesis

None of these

Asexual reproductive structures of chlamydomonas and penicillium are *

1 point

Buds and gemmules respectively

Zoospores and conidia respectively

Zygospore and conidia respectively

Zygote and conidia respectively

Identify the correct events in sexual reproduction in animals *

1 point

Gametogenesis → Gamete transfer → Fertilisation → Zygote formaion → Embryogenesis → Parturition

Gametogenesis → Fertilisation → Zygote formaion → Gamete transfer → Embryogenesis → Parturition

Gametogenesis → Gamete transfer → Embryogenesis → Fertilisation → Zygote formaion → Parturition

Gametogenesis → Gamete transfer → Fertilisation → Embryogenesis → Zygote formaion → Parturition

The membranous cover of the ovum at ovulation is *

1 point

Corona radiata

Zona radiata

Zona pellucida

Chorion

Biological process in which an organism gives rise to young one(s) similar to itself is known as *

1 point

Meiosis

Reproduction

Asexual reproduction

Sexual reproduction

The phenomenon wherein the ovary develops into a fruit without fertilisation is called *

1 point

Parthenocarpy

Apomixis

Asexual reproduction

Sexual reproduction

Choose a correct option of living organisms in which cell division itself is the mode of asexual reproduction. *

1 point

Hydra and planaria

Yeast and amoeba

Sponge and aspergillus

Ascaris and wuchereria

Ploidy of chromosomes in haploid ovum and diploid zygote are *

1 point

2n and n respectively

3n and 2n respectively

2n and 2n respectively

n and 2n respectively

The units of vegetative propagation are termed *

1 point

Eyes

Leaf buds

Vegetative propagules

Seeds

Which one of the following is not a male accessory gland? *

1 point

Seminal vesicle

Ampulla

Prostate

Bulbourethral gland

Identify the correct sequence of events. *

1 point

Gametogenesis → Syngamy → Embryogenesis → Zygote

Gametogenesis → Zygote → Syngamy → Embryogenesis

Gametogenesis → Embryogenesis → Zygote → Syngamy

Gametogenesis → Syngamy → Zygote

Reason for location of the testes in human male outside the abdominal cavity within scrotum is *

1 point

The scrotum helps in protection of primary sex organ of male i.e. testes

The scrotum helps in maintaining the low temperature of the testes (2–2.5 ˚C lower than the normal internal body temperature) necessary for spermatogenesis.

The scrotum helps in maintaining optimum temperature for the entire body of human male.

The scrotum helps in maintaining optimum temperature for the testes and entire body of human male.

Spermiation is the process of the release of sperms from *

1 point

Seminiferous tubules

Vas deferens

Epididymis

Prostate gland

Calculate the number of pollen grains and ovules formed in an anther and the ovary of an angiosperm bearing 20 microspore mother cells and 20 megaspore mother cells. *

1 point

Number of pollen grains produced from 20 microspore mother cells = 20 x 2 =40 pollen grains, Number of ovules produced from 20 megaspore mother cells = 20 X 1= 20 ovules

Number of pollen grains produced from 20 microspore mother cells = 20 x 4 =80 pollen grains, Number of ovules produced from 20 megaspore mother cells = 20 X 2= 40 ovules

Number of pollen grains produced from 20 microspore mother cells = 20 x 4 =80 pollen grains, Number of ovules produced from 20 megaspore mother cells = 20 X 1= 20 ovules

All the options are correct

A particular species of plant produces light, non-sticky pollen in large numbers and its stigmas are long and feathery. These modifications facilitate pollination by *

1 point

Insects

Water

Wind

Animals

In animals, juvenile phase is followed by *

1 point

reproductive phase

senescent phase

old age

vegetative phase

Mature Graafian follicle is generally present in the ovary of a healthy human female around *

1 point

5 – 8 day of menstrual cycle

11 – 17 day of menstrual cycle

18 – 23 day of menstrual cycle

24 – 28 day of menstrual cycle

Reason for location of the testes in human male outside the abdominal cavity within scrotum is *

1 point

The scrotum helps in protection of primary sex organ of male i.e. testes

The scrotum helps in maintaining the low temperature of the testes (2–2.5 ˚C lower than the normal internal body temperature) necessary for spermatogenesis.

The scrotum helps in maintaining optimum temperature for the entire body of human male.

The scrotum helps in maintaining optimum temperature for the testes and entire body of human male.

Nature of sex of a fungi with both male and female reproductive systems is *

1 point

Heterothallic

Homothallic

Famale

Male

Appearance of vegetative propagules from the nodes of plants such as sugarcane and ginger is mainly because *

1 point

nodes are shorter than intenodes

nodes have meristematic cells

nodes are located near the soil

nodes have non-photosynthetic cells

The specialised cells that undergo meiosis to produce haploid gametes is *

1 point

Spermatozoa

Ovum

Meiocytes

Somatic cells

Choose the factors affecting reproduction *

1 point

Size, shape, colour and height of the organism

Habitat and internal physiology of the organism

Nutrition, respiration and circulation of the organism

Number of chromosome and ability to produce gametes

Earthworms and sponges are *

1 point

Hermaphrodite

Unisexual

Homothallic

Heterothallaic

The terms homothallic and monoecious are used to denote *

1 point

unisexual condition

bisexual condition

staminate flowers

pistillate flowers

Which among the following has 23 chromosomes? *

1 point

Spermatogonia

Zygote

Secondary oocyte

Oogonia

Both gynoecium and androecium are present in *

1 point

Monoecious plant

Dioecious plant

Both monoecious and dioecious plants

None of these

Asexual reproduction in plant is called *

1 point

Spore formation

vegetative reproduction or vegetative propagation

Germination

Development of ovules into seed

Morula is a developmental stage *

1 point

Between the zygote and blastocyst

Between the blastocyst and gastrula

After the implantation

Between implantation and parturition

Examples of unicellular organisms which reproduce asexually and shift to sexual reproduction just before the onset of adverse conditions are *

1 point

Amoeba and yeast

Algae and fungi

Paramecium and yeast

Amoeba and paramecium

The number of chromosomes in the shoot tip cells of a maize plant is 20.The number of chromosomes in the microspore mother cells of the same plant shall be: *

1 point

Vegetative propagation in water hyacinth occurs with *

1 point

sucker

offset

runner

rhizome

biological process that enables continuity of species is *

1 point

nutrition

reproduction

excretion

respiration

Term used for the milk produced during the initial few days of lactation towards the end of pregnancy and name of the antibodies rich in it which is essential to develop resistance for the new-born babies are *

1 point

milk and IgA respectively

lactogen and IgM respectively

colostrum and IgA respectively

Colostrum and IgE respectively

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