Class 12th Biology - Biotechnology and its Applications Case Study Questions and Answers 2022 - 2023
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Biotechnology and its Applications Case Study Questions With Answer Key
12th Standard CBSE
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Reg.No. :
Biology
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After green revolution, now a stage has come when further increase in crop yield with the existing crop varieties is not possible. Use of agro-chemicals is two expensive for the farmers and are too harmful for animals and the environment. The answer to the questions whether there is a method to increase the yield and reduce the use of agro-chemicals, is the use of genetically modified (GM) crops.
Write six points on the advantages ofthe GM crops.(a) -
Two of the steps involved in producing nematoderesistant tobacco plants based on the process of RNAi are given. Write the missing steps in proper sequence in the blank spaces a, c, d, f, g and h provided.
(a) -
In mammals, insulin is synthcsised as a pro-hormone. Observe the diagram showing the maturation of pro-insulin into insulin given below and answer the questions that follow.
(a) Why is it called pro-insulin?
(b) Mention the chemical changes that the proinsulin undergoes to become the mature functional insulin.
(c) What is the challenge in the production ofinsulin using rDNA techniques?(a) -
A child is born with a very weak immune system due to the deficiency of an enzyme; it is a hereditary disorder. The doctor explained the available methods of treatment and advised for gene therapy.
(a) Identify the deficient enzyme and the cause of it.
(b) What is gene therapy?
(c) ame two other methods available for the treatment of this disease.(a) -
For effective treatment of a disease, early diagnosis and understanding its pathophysiology is important But, the presence of a pathogen is normally suspected, only when the pathogen produces the symptom(s) of the disease. By this time, the concentration of the pathogen must have become very high in the body.
(a) Expand PCR.
(b) How is it used in early diagnosis of a disease?
(c) Name a disease for the detection of which PCR is routinely used.
(d) Name two other molecular diagnostics used in early detection of diseases.(a) -
The diversity of rice in India is one of the richest in the world. There are an estimated 200,000 varieties of rice in India alone. Among these, Basmati rice is distinct for its unique aroma and flavour. In 1997, an American company got patent rights on Basmati rice, which allowed the company to sell a 'new' variety of Basmati in the U.S and abroad.
(a) How many documented varieties of Basmati are grown in India?
(b) What is the 'new' variety of Basmati, developed by the U.S. company?
(c) Name two other medicinal plants for which the MNCs have been attempting to get patents.(a) -
A multinational company (XYZ) marketed a medicine extracted from medicinal herbs grown in the sprawling fields in a foreign country. This herb is found growing in our country only and no compensation was paid or permission taken from the relevant authority.
(a) What is the term used to refer to such an act committed by the multinational company?
(b) Justify the meaning of the term.
(c) What has the Indian Government done to prevent such deeds?(a) -
Read the following and answer any four questions from (i) to (v) given below:
Golden rice was engineered from normal rice by Potrykus and Beyer in the 1990s. The typical golden colour is due to the production of \(\beta\) carotene a precursor of vitamin - A. Golden rice differs from its parental strain by the addition of three \(\beta\) carotene genes. These included two genes from daffodil plant and third from a bacterium. The incorporation of these genes allows the rice plant to modify certain metabolic pathways in its cells to produce \(\beta\)-carotene.
(i) Due to genetic modification golden rice plants produce and store \(\beta\) - carotene in(a) stem (b) seed (c) leaves (d) all of these (ii) Transfer of genes to produce golden rice is achieved by
(a) Agrobacterium (b) pBR322 (c) \(\lambda \text { -phage }\) (d) gene gun (iii) In golden rice two genes were taken from
(a) Narcissus sp. (b) Erwinia (c) Coryza sativa (d) none of these (iv) Golden rice is helpful to fight against disease caused by the deficiency of
(a) Vitamin Bl2 (b) Vitamin C (c) Vitamin A (d) Vitamin D. (v) Golden rice was genetically engineered by
(a) Fire and Mello (b) Potrykus and Beyer (c) Banting and Best (d) Kohler and Milstein (a) -
Read the following and answer any four questions from (i) to (v) given below :
Plants having foreign genes in their genome through genetic engineering are called transgenic plants. Genes can be incorporated either through a vector or through direct introduction of DNA. Bt cotton is a genetically modified organism which is pest resistant. It contain gene cry I Ac and cry II Ab of Bacillus thuringiensis. It is used to controllepidopterans, coleopterans and dipterans. Bt cotton can resist cotton bollworm and produce higher yields. Cry gene produces cry protein or Bt toxin. It is an endotoxin which remains as protoxin in plants and converted to active toxin after getting ingested by the insects. Alkaline pH of the insect gut solubilises the protein crystals, the activated toxin creates pores to the mid guts wall of the insects which cause them to death.
(i) Bt cotton crops are(a) fungal resistant (b) insect resistant (c) drought resistant (d) all of these (ii) Cotton bollworms are killed by the protein encoded by the gene
(a) cry I Ac (b) cry I Ab (c) cry II Ab (d) both (a) and (c). (iii) Which of the following is not an advantage of GM crops?
(a) GM plants enhance nutritional value of food. (b) GM plants are more tolerant to abiotic stresses. (c) GM plants have helped to reduce post harvest losses. (d) GM plants can cause gene transfer to non-target plant species. (iv) Bacillus thuringiensis is a
(a) air borne bacteria (b) soil borne bacteria (c) soil borne fungus (d) food borne bacteria. (v) Assertion : Cotton bollworms are killed by ingesting the leaves of the transgenic plant.
Reason : Bt toxin binds with the midgut wall of the insect and make pores in them.(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. (a) -
Read the following and answer any four questions from (i) to (v) given below:
Transgenic animals can serve as factories that in some cases, may produce large amount of proteins more efficiently. Transgenic mice have been engineered to express human antibodies by introducing large segment of human DNA encoding human immunoglobulin genes. In transgenic large animals such as cow or sheep proteins of pharmaceutical value can be produced in large quantities in milk which is later purified. Transgenesis can be used to alter many phenotypic properties including growth rate, fat composition, milk production, hair texture, etc.
(i) The production of transgenic animals includes(a) identification and separation of desired gene (b) combining the desired gene with appropriate vector (c) introduction of vector in cells, tissues or embryos (d) all of these. (ii) In transgenic animals, i.e., cow and sheep proteins of pharmaceutical value are produced in large quantities in the
(a) blood (b) accumulated fat (c) mammary glands (d) none of these. (iii) Mouse is mostly preferred animal for studies on gene transfer because
A. short oestrous cycle
B.long gestation period
C.Short generation time
D.Production of one or two offspring per pregnancy(a) both (A) and (C) (b) both (A) and (B) (C) Only D (d) both (C) and (D). (iv) Transgenic genes alter many phenotypic properties including
(a) growth rate (b) fat composition (c) milk production (d) all of these (v) Assertion : Transgenic mice have been engineered to express human antibodies.
Reason : Large segment of human DNA encoding human immunoglobulin have been transferred to mice.(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 (a) -
Read the following and answer any four questions from (i) to (v) given below:
Transgenic cows have extra gene or genes inserted into their DNA. Firstly the genes for the desired product is identified and sequenced. Then a gene construct containing this desired gene is introduced into female cow cells. Transgenic bovine cells are selected and fused with bovine oocytes that have had all of their chromosomes removed. Once fused with the oocyte, the transgenic cells chromosomes are reprogrammed to direct development into an embryo which can be implanted into a recipient cow. The resulting transgenic cow only express the trans gene in her milk. This is because expression of the trans gene is controlled by a promoter specific to lactating mammary cells. The first transgenic cow was 'Rosie:
(i) The gene construct with desired gene is introduced into female cow cells by(a) transformation (b) transduction (c) transfection (d) transplantation. (ii) Production of transgenic cow fulfill the objective of
(a) increased milk production (b) increased meat production (c) molecularfarming (d) all of these (iii) The name of first transgenic cow is
(a) Tracy (b) Dolly (c) Rosie (d) AND!. (iv) Transgenic cow is produced through the implantation of _____containing transgene into recipient cow.
(a) ova (b) embryo (c) mammary cell (d) both (a) and (b) (v) Assertion : Transgenes only express in the mammary glands of transgenic cow.
Reason : Transgenes are present in chromosomes of every cell in transgenic cow(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) Asgertion is true but reason is false. (d) Both assertion and reason are false. (a) -
Read the following and answer any four questions from (i) to (v) given below:
European patent office, Munich granted patent for fungicidal use of neem oil, to firm of WR. Grace & Co. It was challenged by Vandana Shiva and Ajay Phadke who had researched neem in India and it was shown that Grace & Co. had not unveiled any novelty factor in neerns properties. Ethics include rules of conduct by which a community regulates the behaviour and decides as to which activity is lawful and which is not.
(i)_________ allow private, monopoly right over animals and plants.(a) Bioethics (b) Biopatents (c) Bioweapons (d) Either (a) or(b) (ii) Which of the following is not a criteria of granting patent?
(a) Novelty (b) Utility (c) Non-obviousness (d) Prior art (iii) On which plants patents have been granted?
(a) Piper nigrum (b) Brassica campestris (c) Punica granataum (d) All of these (iv) Rules of conduct that may be used to regulate our activities in relation to biological world are included in
(a) bioethics (b) biopiracy (c)biopatents (d) biowar (v) Assertion : Genes and cells should not be patented.
Reason : Genes and cells are not an inventions(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 arid reason are false (a) -
Read the following and answer any four questions from (i) to (v) given below:
Insulin used to cure diabetes was earlier extracted from pancreas of slaughtered cattle and pigs. Insulin extracted from an animal source, though caused some patients to develop allergy or other types of reactions to the foreign protein. Human insulin consists of two short polypeptide chains: chain A and chain B, that are linked together by disulphide bridges. In mammals including humans, insulin is synthesised as a pro-hormone which contains an extra stretch called the C-peptide. This C peptide is not present in mature insulin and is removed during maturation into insulin.
(i) Identify A in the given figure.
(a) Polypeptide chain A (b) Polypeptide chain B (c) Polypeptide chain C (d) None of these (ii) The following is a list of some stages involved in producing human insulin from genetically engineered bacteria.
1. The bacteria are cultured in a fermenter for large scale production.
2. Recombinant insulin is extracted from the bacterial cells that expresses insulin gene.
3. The same restriction enzyme is used again to cut the bacterial plasmid for insertion of the human insulin gene.
4. Bacteria take up the plasmid carrying the insulin gene.
5. A restriction enzyme is used to cut human DNA to extract the insulin gene.
Select the correct order of these stages.(a) 1,5,3,4,2 (b) 2,4,3,5,1 (c) 4,5,3,2,1 (d) 5,3,4,1,2 (iii) To insert the insulin gene into bacterial DNA, both the bacterial plasmid and the human chromosome containing the insulin gene are treated with the same restriction enzyme. Using the same restriction enzyme ensures that
(a) DNA ligase is able to join the segments of human and bacterial DNA (b) the exact length of nucleotides matching the insulin gene is removed from the plasmid (c) both the bacterial and human DNA will contain sticky ends (d) Sticky ends in the cut plasmid and insulin gene are complementary. (iv) Why is the fermentor important for the production of human insulin by transgenic bacteria
(a) It provides optimal conditions for the transgenic to multiply rapidly. (b) It facilitates the extraction and purification of insulin from the transgenic bacteria. (c) It maximise the rate of fermentation of the transgenic bacteria. (d) It provides the low-oxygen conditions that are important for insulin production. (v) A bacteriologist carries out his first attempt at engineering E.coli with the gene for human insulin. During the process, he realises that his stock of DNA ligase has depleted but decides to continue anyway. What is a likely consequence of his decision?
(a) Bacteria with the rDNA will not be able to form colonies in a fermenter (b) The resulting plasm ids are not able to enter the E.coli bacteria even after applying heat shock. (c) The resulting E.coli bacteria do not contain the human insulin gene. (d) The bacterial plasm ids do not have sticky ends and are unable to accommodate the human gene. (a) -
Read the following and answer any four questions from (i) to (v) given below:
Gene therapy is the technique of genetic engineering to replace a faulty gene by a normal healthy functional gene. It is a way of treating genetic disease by introducing a piece of DNA into the cells of an affected individual. Liposomes can be used for gene therapy as they target the cells affected by a genetic disease.
(i) A patient suffers from adenosine deaminase (ADA) deficiency, an autosomal recessive immune deficiency in which bone marrow lymphoblasts cannot replicate to generate immuno-competent lymphocytes. The treatment option that would cure the patient is(a) germ-line gene therapy to replace one ADA gene copy (b) germ-line gene therapy to replace both ADA gene copies (c) somatic cell gene therapy to replace both ADA gene copies in circulating lymphocytes (d) somatic cell gene therapy to replace one ADA gene copy in bone marrow lymphoblasts. (ii) Which type of gene therapy is least effective in transferring DNA to the nucleus?
(a) Adenoviruses` (b) DNA attached to a ligand (c) Liposomes (d) Retroviruses (iii) Liposomes can be used for gene therapy as they target the cells affected by a genetic disease. The diagram shows the structure of a liposome.
What feature of a cell surface membrane allows the liposome to target cells affected by a genetic disease(a) Carrier molecules (b) Phosphate groups (c) Protein channels (d) Receptor molecules (iv) Which of the following disorders would gene therapy be least effective
(a) Cystic fibrosis (b) Huntington's disease (c) Sickle cell anaemia (d) Type II diabetes (v) Following are some reasons explaining why gene therapy is not yet fully an effective treatment for genetic diseases.
I. Lack of knowledge of DNA sequences
II. Lack of efficient and safe gene delivery system
III. Cost of the technology
IV. Some diseases involve multiple genes
V. Problems with appropriate gene regulation
Select the correct option.(a) I, III and V only (b) II, IV and V only (c) III, IV and V only (d) I, III and IV only (a) -
Read the following and answer any four questions from (i) to (v) given below:
Stem cells hold the potential for manifold applications in biotechnology based next generation therapeutics. Scientists are trying to formulate better and more personalised treatment modalities against some seemingly irremediable diseases, by harnessing body's own stem cells and stem cell niche. Stem cells of different origin and level of potency are being investigated for tissue regeneration, treatment of bone defect, drug testing, gene therapy and cell based therapy for muscle damage, spinal cord injury, cancer therapy, etc. The properties of embryonic and adult stem cells to either self-renew or differentiate into multiple cell lineages make them an attractive source for cell therapies, tissue engineering and as model system for drug screening.
(i) Stem cells are widely used in medical research. Which property of stem cells makes them particularly useful in this research?(a) They can be fused together to form a zygote. (b) They can divide and eventually give rise to a whole organism. (c) They can divide and be made to differentiate into various types of cell. (d) They will continue to divide indefinitely. (ii) Stem cells can be divided into four main types. Which of the four types of stem cell can differentiate into a limited range of tissues?
(a) Adult stem cells (b) Embryonic stem cells (c) Fetal stem cells (d) Zygotic stem cells (iii) Which feature of stem cells obtained from blood in the umbilical cord enables their use in the treatment of a variety of blood cancers?
(a) They can differentiate into bone marrow cells. (b) They can differentiate into any cellular component of blood. (c) They can replace blood stem cells affected by cancer (d) They are totipotent. (iv) The search for pluripotent stem cells is intense. The spermatogonium is the diploid precursor of haploid sperm in the development pathway of mouse gametes as shown below.
Scientists were interested to find out which stages of sperm development have stem cell capacity. Two experiments were carried out using sterile host males with testes that lacked germ cells. The results are shown in the table.
Type of cells used Result Experiment 1 Secondary spermatocytes were injected Fertility was not restored Experiment 2 Spermatogonia were injected Fertility was restored for the rest of the mouse's life What property of a stem cell ISmIssmg m the secondary spermatocytes?
(a) Specialisation (b) Self-renewal (c) Commitment (d) A proper stem-cell niche (v) Which feature of embryonic stem cells (ESCs) is illustrated below?
(a) ESCs are capable of dividing (b) ESCs are multipotent (c) ESCs are pluripotent (d) ESCs show plasticity (a)
Case Study
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Answers
Biotechnology and its Applications Case Study Questions With Answer Key Answer Keys
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Advantages:
(i) Genetic modification has made the crops more tolerant to abiotic stresses like cold, heat, drought, salinity, etc.
(ii) It has reduced the dependence of crops on chemical pesticides as they are made pest-resistant.
(iii) Post-harvest losses are much reduced.
(iv) As the plants have increased efficiency of mineral usage, the early exhaustion of fertility of soil is prevented.
(v) Food produced from GM (Genetically Modified) crops has enhanced nutritional value.
(vi) Genetic modification has been used to create tailormade plants to supply resources such as starch, fuels, pharmaceuticals, etc. to industries -
(a) Isolation of nematode-specific gene.
(c) Production of sense and anti-sense RNA in the host.
(d) Formation of double-stranded RNA.
(f) Silencing of specific mRNA of nematode.
(g) Host expresses the interfering RNA.
(h) Parasite/nematode cannot survive in the host. -
(a) It is called pro-insulin because it needs to be processed before it becomes a mature and fully functional hormone, insulin.
(b) (i) The C-peptide is removed.
(ii) The peptides A and B are joined by disulphide bridges.
(c) The major challenge was getting the two polypeptide chains assembled intoa mature form. -
(a) (i) Adenosine deaminase (ADA) is the deficient enzyme.
(ii) It is caused by the deletion of the gene coding for the enzyme.
(b) Gene therapy refers to a collection of methods that allows the correction of a gene defect that has been diagnosed in a child or embryonic stage.
(c) (i) Enzyme-replacement therapy.
(ii) Bone marrow transplantation. -
(a) Polymerase chain reaction.
(b) By amplification ofthe nucleic acid of the pathogen, when it is in very low concentration, the disease can be diagnosed before the symptoms appear.
(c) Acquired immuno-deficiency syndrome (AIDS).
(d) (i) Enzyme-linked immunosorbent assay.
(ii) Recombinant DNA technology. -
(a) 27 varieties.
(b) The 'new' variety of Basmati has been developed by crossing the Indian Basmati variety with the semi-dwarf varieties of the U.S.
(c) Neem and turmeric. -
(a) Biopiracy
(b) Biopiracy refers to the use of bioresources by multinational companies and other organisations without proper authorisation from the countries and people concerned without compensatory payment.
(c) (i) India has framed the Indian Patents Bill.
(ii) Recently, the parliament has cleared the second amendment of the Indian Patents Bill. -
(i) (b) : Golden rice is a transgenic variety of rice (Oryza sativa) which contains good quantities of\(\beta\)-carotene (provitamin A - inactive state of vitamin A).\(\beta\)-carotene is a principal source of vitamin A. Since the grains (seeds) of the rice are yellow in colour due to \(\beta\)-carotene, the rice is commonly called golden rice.
(ii) (a) : Foreign genes were inserted into the genome of a tempera,te rice variety by using Agrobacterium tumefaciens as the vector.
(iii) (a) : In golden rice, two genes for \(\beta\)-carotene were taken from daffodil (Narcissus sp.) and one gene from a bacterium Erwinia.
(iv) (c) : Golden rice is rich in\(\beta\)-carotene which is a precursor of vitamin A.
(v) (b) : Prof. Ingo Potrykus and Peter Beyer produced genetically engineered rice by introducing three gene associated with synthesis of carotene. The grains (seeds) of transgenic rice are rich in provitamin. -
(i) (b) : The genetically modified crop called Btcotton contains Bt toxin genes. The gene cry 1 Ac and cry II Ab control cotton bollworms. Similarly, cry I Ab has been introduced in Bt corn to protect the same from corn borer.
(ii) (d) : cry I Ab has been introduced to Bt corn to protect them from corn borer. cry I Ac and cry II Ab control cotton bollworms.
(iii) (d) : Gene transfer to non-target plant species is a major disadvantageous concern of GM plants. It can even cause to produce 'superweeds'
(iv) (b)
(v) (a): The Bt toxin proteins exist as inactive protoxins but once an insect ingests the inactive toxin it is converted into an active form of toxin due to the alkaline pH of the alimentary canal that solublises the crystals. The activated toxin binds to the surface of midgut epithelial cells and create pores which cause cell swelling and lysis and finally cause death of the insect. -
(i) (d)
(ii) (c)
(iii) (a) : Mouse has short gestation period and it produces several number of offspring per pregnancy.
(iv) (d)
(v) (a) -
(i) (c)
(ii) (d) : The two chief objectives of transgenic cow production are as follows: (i) increased milk and meat production and (ii) molecular farming.
(iii) (c)
(iv) (b) : Transgenic bovine cells are selected and fused with bovine oocytes that have had all its chromosomes removed. Once fused with oocyte, the transgenic cells chromosomes are reprogrammed to direct development into embryo which is implanted into recipient cow.
(v) (b) -
(i) (b) : A patent is the right granted by a government to an inventor to prevent others from commercial use of his invention. Biopatent system allows private, monopoly rights over cells, genes, animals and plants.
(ii) (d) : Patents are supposed to satisfy three criteria of novelty, non-obviousness and utility.
(iii) (d) : Patents have been taken out on plants such as black pepper, basmati rice, Indian mustard, Pomegranate, Turmeric and neem.
(iv) (a)
(v) (a) : Genes, cells, micro-organisms, plants and animals are not inventions and hence must not be patented. -
(i) (c) : A represents polypeptide chain C which is removed prior to insulin formation.
(ii) (d)
(iii) (d) : Each particular restriction enzyme produces unique sticky ends. Using the same enzyme for both the bacterial and human DNA will produce complementary sticky ends that can bind together by complementary base pairing. This would allow the human insulin gene to be inserted into the plasmid.
(iv) (a) : The optimal temperature, pH, oxygen and nutrient conditions in the fermenter allow the bacteria containing the insulin gene to reproduce quickly and produce large quantities of it.
(v) (c) : DNA ligase forms strong hydrogen bonds between the DNA bases on the human insulin gene and the bacterial plasmid, producing a continuous double stranded DNA loop. Without DNA ligase, the human insulin gene, despite being able to undergo complementary base pairing with the bacterial DNA at the sticky ends would not be securely inserted into the plasmid. Thus, the resulting E.coli bacteria would receive plasm ids that lack the human insulin gene. -
(i) (d)
(ii) (b) : Viral delivery using adenoviruses and retroviruses are specific and ensure effectiveness. The viral vector recognises and bind to receptor on cell and enters cells. The vector is able to deliver genes to specific target tissaes and is able to deliver DNA to thenucleus.
(iii) (d) : The liposome's glycolipid membrane containing specific carbohydrates recognises and binds to receptor molecules on cell surface membrane of target cells. The liposome is thus able to deliver genes to specific target cells and is able to deliver DNA into the cell.
(iv) (d) : Type II diabetes is a type of multifactorial and polygenic (complex) disorder where manifestation of disease may be dependent on the effects of multiple genes in combination with lifestyle and environmental factors.
(v) (b) -
(i) (c) : Stem cells are capable of dividing indefinitely and producing copies of themselves. In addition, stem cells can undergo differentiation giving rise to specialized cell types.
(ii) (a) : Adult stem cells are tissue specific and can enter normal differentiation pathways to form only the specialized cell types of the tissue which they reside in.
(iii) (b) : Umbilical cord blood stem cells are multipotent in that they have the ability to differentiate into limited cell types to give rise to a range of specialized cells that have a specific function. Umbilical cord stem cells found in blood only can differentiate into any cellular component of blood, e.g., white blood cells (such as B lymphocytes, T lymphocytes, natural killer cells, macrophages and platelets etc.) vital for fighting infections and safeguarding the body, red blood cells - important for transporting oxygen to cells.
(iv) (d) : Stem cell niche is used to describe the microenvironment in which stem cells are found. Since fertility was restored after the injection of spermatogonia, it suggests that spermatogonium displays the general properties of stem cells such as being capable of dividing indefinitely and producing copies of themselves (self-renewal), can undergo differentiation giving rise to specialised cell types (haploid sperm). As fertility was not restored upon injection of secondary spermatocytes, it suggest that the secondary spermatocytes do not have a stem cell niche and do not display the properties of stem cell.
(v) (c) : Embryonic stem cells are pluripotent cells. That is, they have the ability to develop into almost any kind of cell in the body (as seen from diagram, hematopoietic SCs, neural SCs and mesenchymal SCs) except extra-embryonic membrane (but not the trophoblast).