MONTHLY TEST FOR AUGUST CLASS TWELEV (XII) BIOLOGY)

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XII MONTHLY TEST-AUGUST
SUBJECT :		BIOLOGY	CLASS               :	XII Sc
TIME        :			MAX. MARKS  :
INSTRUCTIONS:
(i) All questions are compulsory. (ii) Question numbers 1 to 12 are MCQ and carry one mark each. (iii) Question numbers 13 to 18 are ASSERTION REASON TYPE and carry one mark each. (iv)  Question numbers 19 to 22 are SA-1 and carry two marks each. (v)  Question numbers 23 to 27 are SA-2 and carry three marks each. (vi) Question number 28  is LA-1 and carries five marks. (vi)Question numbers 29 is LA-II(CASE BASED) and carry 5 marks . (vii)There is no overall choice. (viii)Draw neat labelled diagrams wherever necessary.
Q.1.	For three generations, E. coli growing in a medium containing radioactive thymidine was allowed to grow in a standard medium(without radioactive thymidine ). What percentage of bacteria will have a radioactive DNA strand? a. 100%  b.50 % c. 25 % d. 12.5%
Q.2.	Which of the following is valid for the promoter and terminator of a transcription unit? a.       Both flanks of the structural gene                  b. The promoter is upstream of the structural gene in coding strand polarity.  C. Terminator is downstream of the structural gene concerning coding strand polarity d. all of the above
Q.3.	If the gene frequency between genes a and c is 2%, b and c is 13%, b and d is 4%, a and b is 15%, c and d is 17%, and a and d is 19%. A chromosome’s gene sequence is called 1.a,d,b,c  2.d,b,a,c  3.a,b,c,d   4.a,c,b,d
Q.4.	Which of the following doesn’t agree with the chromosomal theory of inheritance? a)       The genes are located on the chromosome      b) The genes on the same chromosome are always passed together               c) The genes are located linearly on the chromosomes             d) The distance between two genes can be mapped
Q.5.	Match the RNA polymerase types in column I with that of the product they synthesise in column II.   Column I                                                             Column II a. RNA pol. I                                      i. Synthesizes mRNA and hnRNA b. RNA pol. II                                    ii. Synthesises tRNA, five srRNA, Sn RNA in nucleolus c. RNA pol. III                                    iii. Synthesizes rRNA (28S, 18S) in nucleolus   A .a- i, b – ii, c – iii                                 B .a – ii, b – iii, c – i C .a – iii, b – i, c – ii                                D .a – iii, b – ii, c – i
Q.6	What are the differences in the specific regions of DNA sequence called during DNA fingerprinting? a) Non-repetitive DNA b) Repetitive DNA c) Satellite DNA d) Histone DNA
Q.7	What are the small peaks achieved by the repetitive DNA during the density gradient centrifugation process of DNA fingerprinting? a) Non-repetitive DNA b) Trough c) Satellite DNA d) Histone DNA
Q.8	A gene with axial and terminal alleles determines flower position in pea plants. Given that the axial is dominant to the terminal, list all possible F1 and F2 genotypes and phenotypes from a cross involving homozygous parents for each trait—express genotypes with conventional genetic abbreviations. a)F1: All AA-axial; F2: AA-Axial and aa-terminal. b)F1: All aa-terminal; F2: AA-Axial and Aa-terminal. c)F1: AA-axial and Aa-terminal; F2: All AA-axial. d)F1: All Aa-axial; F2: AA-Axial, Aa-Axial, and aa-terminal.
Q.9	Can a human male be a carrier of red-green colour blindness? a)Yes, males can be the carriers of red-green colour blindness, as colour blindness is autosomal dominant. b)No, males cannot be the carriers of red-green colour blindness, as colour blindness is X-linked. c)No, males cannot be the carriers of red-green colour blindness, as colour blindness is Y-linked. d)Yes, males can be the carriers of red-green colour blindness, as colour blindness is autosomal recessive.
Q.10	The blood type that is always evidence of a homozygous genotype is: A) A                                 B) B                     C) AB              D) O       E) Both A and B are correct
Q.11	_____ incompatibility prevents cross-pollination. a) Intraspecific b) Self c) Interspecific d) Outbreeding
Q.12	Zoster is an example of ______ a) pollination by animals b) pollination by wind c) pollination by water d) pollination by birds
	ASSERTION REASONING QUESTIONS Directions: Each of the following questions contains a statement of assertion, and a corresponding statement of reason is below it. Choose the correct option given under each question. (A) Both assertion and reason are true, and reason is the correct explanation of assertion.      (B) Both assertion and reason are true, but reason is not the correct explanation of assertion. (C) Assertion is true, but reason is false.                    (D) Both Assertion and Reason are false.
Q.13	Assertion: Intra cytoplasmic sperm injection (ICSI) is a procedure to form an embryo in vitro. Reason: In ICSI, sperm is directly injected into the ovum.
Q.14	Assertion: IUT is the transfer of an embryo with more than eight blastomeres into the fallopian tubes. Reason: IUT is a prevalent method of forming embryos in vivo.
Q.15	Assertion: In the morula stage, cells divide without increasing in size. Reason: Zona pellucid remains undivided till cleavage is complete.
Q.16	Assertion (A): Endosperm development precedes embryo development. Reason(R): During endosperm development, the PEN initially undergoes successive nuclear divisions to give rise to free nuclei.
Q.17	Assertion: The probability of DNA polymorphism would be higher in coding DNA strands. Reason: Mutations in these sequences may not immediately affect an individual's reproductive ability.
Q.18	Assertion (A): Pleiotropic gene affects multiple traits Reason (R ): ABO blood group is an example of Pleiotropism
Q.19.	A flower of a tomato plant following the process of sexual reproduction produces 240 viable seeds. The endosperm of the seed contains 90 chromosomes. Answer the following questions giving reasons: (a) What is the minimum number of pollen grains that must have been involved in pollinating its pistil? (b) How many megaspore mother cells were involved? (c) What is the minimum number of microspore mother cells involved in the above case? (d) What is the number of chromosomes in the embryo?
Q.20	. The placenta acts as an endocrine tissue. Justify.
Q.21	A woman has specific queries, as listed below, before starting with contraceptive pills. Answer them. (a) What do contraceptive pills contain, and how do they act as contraceptives? (b) What schedule should be followed for taking these pills?
Q.22	A blue-eyed child has a brown-eyed mother and a brown-eyed father. From this family alone, would you think blue eyes result in a recessive gene, a dominant gene, polygenic inheritance or an intermediate gene? Give reasons for your answers.
Q.23	Where do transcription and translation occur in bacteria and eukaryotes, respectively? Explain the complexities in transcription in eukaryotes that are not seen in bacteria.
Q.24	Trace the development of an endosperm after fertilisation using the coconut. Mention the importance of endosperm development.
Q.25	Mature seeds of legumes are non-albuminous. Can it be assumed that double fertilisation does not occur in legumes? Explain your answer,
Q26	What are the two major approaches in the methodologies of HGP? What is the need for sequencing the rice genome?
Q.27	Describe the process of Oogenesis Schematically
Q.28	. a.       What is the significance of LH  surge at the ovarian level? b.       What impact will lowering progesterone secretion from the corpus luteum be? c.       What are the changes that take place in the uterus during the follicular phase? d.       What layer of the uterus is shredded during menstruation?  a) Perimetrium b) Myometrium  c) Epimetrium   d) Endometrium
Q.29	Chromosomal and gene disorders are genetic conditions affecting an individual's physical and mental health. These disorders occur due to abnormalities in chromosomes or genes responsible for carrying and transmitting genetic information. Chromosomal disorders, such as Down syndrome, happen when an extra or missing chromosome is in an individual's cells. Gene disorders, conversely, result from mutations or changes in specific genes. Examples of gene disorders include cystic fibrosis, sickle cell anaemia, and muscular dystrophy. Symptoms of chromosomal and gene disorders vary widely and can affect different bodily systems and functions. Identifying these disorders early on is crucial to providing appropriate medical interventions and support for affected individuals and their families. 1. Which disorder is caused by an extra chromosome 21? a) Sickle cell anaemia b) Down syndrome c) Cystic fibrosis d) Muscular dystrophy 2. What is the medical term for Down's syndrome? a) Monosomy 21     b) Trisomy 18   c) Trisomy 21           d) Monosomy X 3. Which disorder is characterised by abnormal haemoglobin molecules in red blood cells? a) Down syndrome b) Sickle cell anaemia c) Cystic fibrosis d) Muscular dystrophy 4. What is the leading cause of sickle cell anaemia? a) Extra chromosome 21                             b) Missing chromosome X c) Mutation in the CFTR gene                     d) Mutation in the haemoglobin gene 5. Which type of disorder is caused when phenyl pyruvic acid is excreted through the urine? a) Autosomal dominant                                 b) Autosomal recessive c) X-linked dominant                                     d) X-linked recessive