Test 3 (Class 12)- Recall (Old NCERT)

Biology 1 - Section A

1.

The testes are situated outside the abdominal cavity within a pouch called the scrotum. This is necessary as:

1.	The scrotum can contain lengthy ducts for the transfer of sperms
2.	Scrotum helps in maintaining the low temperature of the testes necessary for spermatogenesis
3.	Scrotum reduces the pressure around the testes necessary for spermatogenesis
4.	Scrotum can store huge amounts of sperms

2.

Corpus luteum is essential for:
1. Release of ovum
2. Development of follicles
3. Maintenance of endometrium
4. Contraction of the myometrium

3.

The sobriquet ‘terror of Bengal’ has been given to:

1.	Pistia	2.	Lemna
3.	Eichhornia	4.	Zostera

4.

Identify the incorrectly matched pair:

1.	Triploid nutritive tissue of a seed deposited externally to the embryo sac	Perisperm
2.	The tissue that arises from the ripened ovary wall of a fruit; the fruit wall	Pericarp
3.	The natural or artificially induced production of fruit without fertilisation of ovules	Parthenocarpy
4.	Asexual reproduction where the growth and development of embryos occur without fertilization by sperm	Parthenogenesis

5. Consider the given two statements:

Statement I:	When offspring is produced by a single parent but always with the involvement of gamete formation, reproduction is asexual.
Statement II:	When two parents [opposite sex] participate in the reproductive process and also involve the fusion of male and female gametes, it is called sexual reproduction.

1.	Statement I is correct, Statement II is incorrect.
2.	Statement I is correct, Statement II is correct.
3.	Statement I is incorrect, Statement II is correct.
4.	Statement I is incorrect, Statement II is incorrect.

6.

The spermatids are transformed into spermatozoa by a process called:

1.	Spermiation	2.	Spermatocytogenesis
3.	Spermiogenesis	4.	Spermatolysis

7.

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

1.	Parthenocarpy	2.	Apomixis
3.	Asexual reproduction	4.	Sexual reproduction

8.

The signals of fetal ejection reflex originate from:
1. Maternal pituitary
2. Maternal hypothalamus
3. Fully developed fetus and placenta
4. Fetal pituitary

9.

The trophoblast cells of the blastocyst form:

1.	Embryo	2.	Umbilical cord
3.	Placenta	4.	Teratoma

10.

What is released at ovulation?

1.	Primary oocyte arrested at meiosis I
2.	Primary oocyte arrested at meiosis II
3.	Secondary oocyte arrested at meiosis I
4.	Secondary oocyte arrested at meiosis II

11.

Which hormone is mainly secreted by the developing follicles during the proliferative phase of the menstrual cycle?

1.	LH	2.	FSH
3.	Progesterone	4.	Estrogen

12.

Plants have developed many mechanisms to encourage cross-pollination that include:

I:	Asynchrony between pollen release and stigma receptivity
II:	Placing of pollen and stigma at different positions
III:	Self-incompatibility
IV:	Dioecy

What would be true regarding these mechanisms?

1.	I and II prevent autogamy and geitonogamy
2.	III is a genetic mechanism that inhibits pollen germination or pollen tube growth
3.	IV is a very common [found in the majority] mechanism seen in flowering plants
4.	I, II, and III invariably lead to xenogamy

13.

Majority of plants:

1.	Use abiotic agents for pollination
2.	Use biotic agents for pollination
3.	Do not use any agent for pollination
4.	Use both abiotic and biotic agents for pollination.

14.

At the birth of the female child, the follicles in her ovaries contain:

1.	Primary oocytes that have been arrested at the S phase of the cell cycle
2.	Primary oocytes that have been arrested at prophase I of meiosis I
3.	Secondary oocytes that have been arrested prophase I of meiosis I
4.	Secondary oocytes that have been arrested at metaphase II of meiosis II

15.

The ‘family planning’ programs in India were initiated in:

1.	1947	2.	1951
3.	1957	4.	1961

16.

Transfer of pollens from the anther to the stigma of the same flower is called:

1.	Autogamy	2.	Geitonogamy
3.	Xenogamy	4.	Cleistogamy

17.

Barrier methods for contraception work on the principle of:
1. Preventing fertilization
2. Preventing implantation
3. Preventing ovulation
4. Preventing embryo development

Biology 1 - Section B

18.

A plant, on repeated self-pollination, preserves the trait expressed for many generations. Such a plant is said to be:

1.	Panmictic	2.	Homologous
3.	Apomictic	4.	Pure line

19.

Mendel’s work remained unrecognised till 1900. Which of the following was not a reason for this?

1.	His work was widely publicised and it brought a bad name to Mendel.
2.	His concept of factors as stable and discrete units that did not ‘blend’ was not accepted.
3.	His approach of using mathematics to explain biological phenomena was unacceptable.
4.	He could not provide any physical proof for the existence of factors or say what they were made of.

20.

The number of alleles, the genotypic combinations, and phenotypes in the ABO system are respectively:

1.	3, 6 and 4	2.	3, 4 and 6
3.	2, 3 and 4	4.	2, 3, and 6

21.

What is the F₂ genotypic ratio in cases of incomplete dominance?

1.	1 : 1	2.	3 : 1
3.	1 : 2 : 1	4.	1 : 1

22.

A high success rate of preventing pregnancy by the insertion of IUD as an emergency contraceptive within 72 hours of coitus suggests that:

1.	There is a latency between the release of the ovum and it getting ready for fertilization
2.	The journey from the point of insemination to the site of fertilization is very long for a very small-sized sperm and takes considerable time.
3.	IUDs may also make the uterine endometrium hostile to implantation.
4.	If the secretion of hCG by the trophoblast cells can be stopped, it will lead to spontaneous abortion as happens due to the insertion of IUDs.

23.

In the ‘test–tube baby’ procedure:

1.	Fertilization is in-vitro but embryo development is in-vivo
2.	Fertilization is in-vivo but embryo development is in-vitro
3.	Both fertilization and embryo development are in-vitro
4.	Both fertilization and embryo development are in-vivo

24.

‘When two pairs of traits are combined in a hybrid, segregation of one pair of characters is independent of the other pair of characters’. This is the statement of:
1. Law of Dominance
2. Law of segregation
3. Law of Independent Assortment
4. Law of Linkage

25.

A graphical representation to calculate the probability of all possible genotypes of offspring in a genetic cross is called as:

1.	Forked line diagram	2.	Punnett square
3.	Pedigree chart	4.	Idiogram

Biology 2 - Section A

26.

Consider the transcription unit given in the following diagram and choose the correct statements:

I:	The promoter on the template is situated upstream and 5’ to the structural gene.
II:	It is the presence of the structural gene that defines the template strand.
III:	The coding strand does not code for anything and is displaced during transcription.

1.	I and II only	2.	I and III only
3.	II and III only	4.	I, II and III

27.

The progeny of a dihybrid test cross AaBb x aabb show the following genotypes: AaBb 160, Aabb 460, aaBb 440, aabb 140. The recombination frequency between the two loci is:

1.	12.5 %	2.	25 %
3.	15 %	4.	30 %

28.

Which of the following codons has a dual role in the genetic code?

1.	AUG	2.	GUG
3.	CUG	4.	UUG

29.

The lac Y gene codes for permease, which increases the permeability of the cell to:

1.	Glucose	2.	Galactose
3.	cAMP	4.	β-galactosides

30. What will be true regarding the comparison of thalassemia and sickle cell anaemia?

1.	The former is a quantitative problem of synthesising too few globin molecules while the latter is a qualitative problem of synthesising an incorrectly functioning globin.
2.	The former is a qualitative problem of synthesising too few globin molecules while the latter is a quantitative problem of synthesising an incorrectly functioning globin.
3.	Both disorders are qualitative problems of synthesising too few globin molecules.
4.	Both disorders are quantitative problems of synthesising too few globin molecules.

31.

In humans, the mechanism of sex determination is:

1.	XX – XY; male heterogamety
2.	XX – XY; female heterogamety
3.	XX – XO; male heterogamety
4.	XX – XO; female heterogamety

32. Consider the two statements:

Statement I:	There is now enough evidence to suggest that essential life processes (such as metabolism, translation, splicing, etc.), evolved around RNA.
Statement II:	DNA being double-stranded and having complementary strands further resists changes by evolving a process of repair.

1. Statement I is correct, Statement II is correct
2. Statement I is correct, Statement II is incorrect
3. Statement I is incorrect, Statement II is correct
4. Statement I is incorrect, Statement II is incorrect

33.

If each strand of a dsDNA acts as a template for a new strand, the two daughter DNAs will be:

1.	Complementary to each other
2.	Identical to the parental DNA
3.	Similar to each other
4.	Complementary to the parental DNA

34.

The physiological basis of pleiotropy is:

1.	lack of independent assortment in linked genes
2.	separation of homologous chromosomes at anaphase I in meiosis I
3.	dominance is not an autonomous feature of an allele
4.	inter-relationships of many metabolic pathways in the living organisms

35.

Consider the following statements:

I.	Deoxyribonucleoside triphosphates act as substrates as well as provide energy for polymerization reaction during DNA replication.
II.	The replication of DNA is both semiconservative and semi-discontinuous
III.	In bacterial DNA replication, there are multiple ori and replication fork moving bi-directionally

Which of the above statements are true?

1.	I and II only	2.	I and III only
3.	II and III only	4.	I, II and III

36.

What facilitates the opening of the helix during the elongation step of transcription?

1.	RNA polymerase	2.	Helicase
3.	Topoisomerase	4.	Gyrase

37.

Which of the following would be nucleoside found only in RNA?

1.	Thymidine	2.	Cytidine
3.	Uridine	4.	Adenosine

38.

Identify the incorrect statement:

1.	In addition to recombination, the mutation is another phenomenon that leads to variation in DNA.
2.	Chromosomal aberrations are commonly observed in cancer cells.
3.	A classical example of a point mutation is sickle cell anemia.
4.	Non-ionising radiations cannot be mutagens.

39.

A segment of DNA coding for a polypeptide is most accurately defined as:

1.	Operon	2.	Gene
3.	Recon	4.	Cistron

40.

Which of the following is also called soluble RNA?

1.	tRNA	2.	rRNA
3.	mRNA	4.	siRNA

41. The figure shows the Meselson and Stahl experiment. Identify the correct statements:

I:	The result at the end of 20 minutes excludes the ‘conservative’ mode of DNA replication.
II:	The result at the end of 40 minutes excludes the ‘dispersive’ mode of DNA replication.

1. Statement I is correct, Statement II is incorrect.
2. Statement I is incorrect, Statement II is correct.
3. Statement I is incorrect, Statement II is incorrect.
4. Statement I is correct, Statement II is correct.

42. The mode of inheritance of the Mendelian disorder shown in the given pedigree chart is most likely:

1. Autosomal recessive
2. Autosomal dominant
3. Sex-linked recessive
4. Sex-linked dominant

Biology 2 - Section B

43. The figure shows a family tree of dinosaurs and their living modern-day counterpart organisms. Study the given two statements:

Statement I:	‘A’ denotes ‘crocodilians’ that have a four chambered heart and endothermy similar to the birds and the mammals.
Statement II:	‘B’ denotes ‘Archaeopteryx’, a connecting link between reptiles and birds and has been found as a complete specimen preserved as fossil.

1. Statement I is correct; Statement II is incorrect
2. Statement I is correct; Statement II is correct
3. Statement I is incorrect; Statement II is correct
4. Statement I is incorrect; Statement II is incorrect

44.

Which one of the following would cause the Hardy-Weinberg principle to be inaccurate?

1.	The size of the population is very large.
2.	Individuals mate with one another at random.
3.	Natural selection is present.
4.	There is no source of new copies of alleles from outside the population.

45.

The natural selection operating as shown in the given figure is called as:

1.	Disruptive
2.	Directional
3.	Stabilizing
4.	Retrogressive

46. The figure shows an experiment that demonstrated that life comes only from pre-existing life. This experiment was conducted by:

1. Spallanzani
2. Francesco Redi
3. Louis Pasteur
4. van Helmont

47.

Southern blotting is transfer to nitrocellulose sheet from agar gel of:

1.	RNA	2.	Proteins
3.	DNA	4.	Lipids

48. The thorn of Bougainvillea and the tendril of Cucurbita are shown in the figure: Identify the correct statement from the ones given below:

I: represent homology
II: are results of convergent evolution

1.	Only I is correct	2.	Only II is correct
3.	Both I and II are correct	4.	Both I and II are incorrect

49. The first human-like being, the hominid, was called:

1.	Homo habilis	2.	Homo erectus
3.	Homo ergaster	4.	Homo neanderthelensis

50. Bryophytes evolved from:

1.	Chlorophyte ancestors	2.	Tracheophyte ancestors
3.	Rhynia-type plants	4.	Psilophytons

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