Subject: Biology
Class XII
Time Allowed: 3 hours
Max. Marks: 70
General instructions
- There are 39 questions in this question paper. All questions are compulsory.
- Section A: Q. No. 1 to 7 are M.C.Q type questions. One mark for each question. Q. No. 8 to 12 are Assertion reason based questions One mark for each question.
- Question number13 and 14 are, passage based questions carrying 4 marks and 5 marks.
- Q. No. 15 to 21 are fill up the blanks. Carry 1 mark for each question.
- Question number 22 to 26 are the questions are based on one-word answer. Carry one mark for each question,
- Question 27 and 28 are, choose the true and false type questions, caring one mark for each question.
- Section B: Q. No. 29 to 32 are short answer questions and carry 2 marks each.
- Section C: Q. No. 33 to 36 are short answer questions and carry 3 marks each.
- Section D: Q. No. 37 to 39 are long answer questions carrying 5 marks each.
- There is no overall choice. However, internal choices have been provided.
- Draw well labeled diagram where required.
Section ‘A’
Q1 in some plants and androecium and stigma grow and mature it same time this phenomenon is called
a) homogamy b) singamy c) allogamy. d) fusion.
Q2 Acrosome of a sperm is a modified
a) lysosome b) Golgi Complex c) nucleus d) mitochondria.
Q3 the function of copper ions in copper releasing IUDs
a) They suppress sperm motility and fertilizing capacity
b) They inhibit gametogenesis
c) They make uterus unsuitable for implantation.
d)They inhabit ovulation.
Q4 A woman has an X- linked condition on one of her X chromosome. This chromosome can be inherited by
a) only daughters b) both sons and daughters c) see only grandchildren d) only suns.
Q5 In a DNA strand the nucleotides are linked together by
a) glycosidic bond b)phosphodiester bonds c) peptide bonds d) hydrogen bonds.
Q6 Wings of Mosquito, bat and bird show evolution called
a) divergent b) convergent c) metamorphosis d) parallel.
Q7 some blue green algae can be used as bio fertilizers because
a) They are photosynthetic b) They grow everywhere
c) They have mucilage d) They fix nitrogen.
Q8 to 12 are assertion reason based questions. Mark the correct choice as
a) Both assertion and reason are true and reason is the correct explanation of assertion.
b) Both assertion and reason are true but the reason is not the correct explanation of assertion.
c) Assertion is a true but reason is false.
d) Assertion is false but a reason is true.
Q8 Assertion: Chasmogamous flowers require pollinating agents.
Reason: Cleistogamous flowers do not expose their sex organs.
Q9 Assertion: Use a condom is a safeguard against AIDS and sexual disease beside checking pregnancy. Reason: Certain contraceptive are planted under the skin of upper arm to prevent pregnancy.
Q10 Assertion: In the human male testis are extra- abdominal and lie in scrotal sacs.
Reason: Scrotum act as thermo regulator and keeps testicular temperature lower by 2 degrees’ Celsius normal spermatogenesis.
Q11 Assertion: Histones are basic protein of major importance in packaging of eukaryotic chromosome DNA and histone comprise chromatin forming the bulk of eukaryotic chromosome.
Reason: Histones are five major types and their nature is basic not the acidic.
Q12 Assertion: Genetic code is universal.
Reason: Genetic code is same for all organisms.
Q13 Read the following text and answer the following questions on the basis of the same.
Implantation is the embedding of the blastocyst into the endometrium of the uterus. Blastocyst is a ball of cells with a large fluid filled cavity called the blastocoel the blastomeres in the blastocyst are arranged into an outer layer called trophoblast and inner cell mass. With the formation of blastocoel. Morula is converted to blastula is called blastocyst in mammals. After it is converted into gastrula having the three germ layers.
i) State of embryo development in which implantation occurs in human female is:
a) morula b) zygote c) blastocyst d) transient three cell stage.
ii) Which organ is formed during gastrulation?
a) Gill b) vitelline membrane c) Archenteron d) heart.
iii) The process that transforms the embryo into a three layered stage is called………
a) blastulation. b) cleavage c) gastrulation d) organogenesis.
iv) The ectoderm cells will form the…..
a) skeletal system b) nervous system c) excretory system d) respiratory system.
Q14 During an argument between two Biology students Raman said that during the course of evolution DNA was chosen over RNA because the former has stable structure and less reactive as compared to the letter. Ajay was not convinced and said that RNA was the first genetic material in organisms.
i) Why RNA is considered unstable over DNA?
ii) Give an evidence that RNA was the first genetic material.
iii) Do humans contain RNA? if yes mention its function.
iv) In which organism RNA play the role of genetic material.
v) Mention any two properties that must be fulfilled by a molecule acting as genetic material.
Question number 15 to 21 are feel up the blanks.
Q15 The structure having clover leaf structure is………
Q16 The evolutionary history of an organisms is called……..
Q17 Single cell protein (SCP) provides a ……… supplement in our diet.
Q18 Aquatic fern which is an excellent biofertilizer is…..
Q19 Linked genes are located in the ……. chromosome.
Q20 The seeds stores reserve food material in endosperm are called……
Q21 Government of India has legalised MTP in……..
Question number 22 to 26 are the questions having the one word answer.
Q22 Surgical removal of a segment of Vasa deferens and the cut ends are ligated is known as..?
Q23 The ability of a gene to have many phenotypic effects is called……
Q24 A sequence of three adjacent to nitrogenous bases in mRNA that code for an amino acid is known as?
Q25 Write the term for transformation of spermatids into sperm.
Q26 Give example of two fruits develops from thalamus.
Question number 27 and 28 are true false type questions write answer in the form of true or false.
Q27 Woman who takes the place of real mother to nurse the embryo is called surrogate mother.
Q28 Humulin is genetically engineered human insulin.
Section ‘B’
Q29 Name an oral pill used as a contraceptive by human females. Explain how does it prevent pregnancy.
Or
Write the features of an ideal contraceptive.
Q30 Explain incomplete dominance with example.
Q31 Write definition with example homologous and analogous organs.
Q32 What is the function of aeration tank in the treatment of sewage?
Section ‘C’
Q33 What is parturition? Which hormones are involved in induction of parturition?
Q34 Explain with diagram mechanism of double fertilization in angiosperm plants with its significance.
Or
Explain polyembryony and partheno- genesis with example.
Q35 A man with blood group AB and his wife with blood group O claim a child with blood group O as their son. Justify with the help of Punnett square whether it is possible or not.
Or
Males are more susceptible to X linked resistive traits then females justify this statement.
Q36 Draw the well labelled diagram of clover leaf model of tRNA and mention the name and function of its arms.
Section ‘D’
Q37 Explain with suitable example mendel’s principle of independent assortment. Up to F2 generation.
Or
In man brown eyes (B)are dominate to blue (b) and dark hair (R) are dominate to red hair (r) A man with brown eyes and red hair (whose father was Blue Eyed) marries a woman with blue eyes and dark hair (but whose mother was red haired) They have four children give the phenotypes and genotypes of the parents and children.
Q38 Answer the following questions based on Harshey and chases’s experiments.
i) Name the kind of virus they worked with and why?
ii) Why did they use two types of culture media to grow viruses in? Explain.
iii) State the conclusion drawn by them after the experiments.
iv) Which molecule they proved as a genetic material.
Or
Explain the process of DNA replication with the help of schematic diagram.
In which phase of the cell cycle does replication occur in eukaryotes? what would happen if a cell division is not a followed after DNA replication.
Q39 Discuss the role of microbes as biofertilizer in detail with example.
Or
Draw the diagram of biogas plant and answer the questions that follow.
i) Name the components gaining entry into the chamber.
ii) Mention the group of Bacteria and the condition in which they act on the component that entered in the digester.
iii) Name the components that get collected in gas holder.