HBSE Class 12 Biology Important Questions Answer 2024 PDF

Class 12 Biology Important Question Answer solution with pdf. Here We Provides Class 1 to 12 all Subjects NCERT Solution with Notes, Question Answer, CBSE and HBSE Important Questions, MCQ and old Question Papers for Students.

HBSE ( Haryana Board ) Solution of Class 12 Biology important Question And Answer solution for 2024 exams.

HBSE Class 12 Biology Important Question 2024

HBSE Class 12 Biology Chapter 1 – Sexual Reproduction in Flowering Plants Important Questions 2024

Q1. With the help of a labelled diagram, describe the structure of a typical anatropous ovule.

Q2. Explain the formation of Embryo sac in plants. Most Important
OR
With the help of diagram, describe the formation of embryo sac from megaspore mother cell in a flowering plants.

Q3. Draw a well labelled diagram of mature embryo sac.

Ans – 

Q4. Draw a diagram of a fertilized embryo sac of a flowering plant. Label all its cellular components.

Ans – 

Q5. Draw a diagram of a section of a mega- sporangium of a flowering plant and label funiculus, micropyle, nucellus and embryo sac in it.

Q6. Describe the structure of pollen grain in detail. Most Important

Q7. Name the organic material exine of the pollengrain is made up of. How is this material advantageous to the pollen grain ?

Q8. Mention various devices to discourage self- pollination and to encourage cross-pollination in flowering plants.

Q9. What are chasmogamous flowers ? Can cross pollination occur in cleistogamous flowers ? Give reasons for your answer.

Q10. Explain megasporogenesis using diagram.

Q11. With the help of diagram describe the stages of embryo development in a dicot flowering plant.

Q12. Draw a diagram of L. S. of an embryo of grass. Label its all the parts. Most Important

Ans – 

Q13. Write about Multiple Ovulation Embryo Transfer Technology (MOET).
OR
Write the full form of MOET.

Q14. Explain the development of endosperm from this embryo sec.

Q15. What is placenta ? Write down its functions. Most Important

Q16. What is autogamy ? Explain this process in oxalis.

Q17. What is ‘autogamy’ ?

Q18. What is bagging technique? How is it useful in a plant breeding programme ?

Q19. What is triple fusion? Where & how does it take place ? Name the nuclei involved in triple fusion.

Q20. Write down the characteristics of wind and insect pollinated flowers. Most Important

Q21. Write briefly about self-incompatibility.

Q22. What is syngamy?

Q23. What is coleorrhiza ? Most Important

Ans – At its lower end, the embryonal axis has the radical and root cap enclosed in an undifferentiated sheath called coleorrhiza.

Q24. What is coleoptile ? Most Important

Ans – The portion of the embryonal axis above the level of attachment of scutellum is the epicotyl. Epicotyl has a shoot apex and a few leaf primordia enclosed in a hollow foliar structure called coleoptile.

Q25. What is Apocarpous and Syncarpous ?
OR
What do you mean by Apocarpous ?

Q26. What is Xenogamy ?

Ans – Transfer of pollen grains from anther to the stigma of a different plant. This is the only type of pollination which during pollination brings genetically different types of pollen grains to the stigma.

Q27. What is perisperm? In which seeds it is present ?

Ans – In some seeds such as black pepper and beet, remnants of nucellus are also persistent. This residual, persistent nucellus is the perisperm.

Q28. What is Geitonogamy?

Ans – Transfer of pollen grains from the anther to the stigma of another flower of the same plant. Although geitonogamy is functionally cross-pollination involving a pollinating agent, genetically it is similar to autogamy since the pollen grains come from the same plant.

Q29. What are false fruits? Give an example.

Ans – In most plants, by the time the fruit develops from the ovary, other floral parts degenerate and fall off. However, in a few species such as apple, strawberry, cashew, etc., the thalamus also contributes to fruit formation. Such fruits are called false fruits.

Q30. What is ‘hypocotyl?

Ans – The cylindrical portion below the level of cotyledons is hypocotyl.

Q31. Explain polyembryony with an example.

Ans – Occurrence of more than one embryo in a seed is referred to as polyembryony. Example – Orange Seed

Q32. Name and explain the nutritive tissue present in Angiosperms. Explain its formation and types.

Q33. Megasporangium is also called __________.

Ans – Ovule

Q34. Describe the structure of megasporangium.

Q35. Write full form of “PMC”.

Ans – pollen mother cell

Q36. What is Emasculation?

Ans – If the female parent bears bisexual flowers, removal of anthers from the flower bud before the anther dehisces using a pair of forceps is necessary. This step is referred to as emasculation.

Q37. What is scutellum ?

Ans – Embryos of monocotyledons possess only one cotyledon. In the grass family the cotyledon is called scutellum that is situated towards one side (lateral) of the embryonal axis.

Q38. What is Chalaza ?

Q39. What is Funicle ?

Ans – The ovule is a small structure attached to the placenta by means of a stalk called funicle.

HBSE Class 12 Biology Chapter 2 – Human Reproduction Important Questions 2024

Q1. Describe the various events in human embryonic development at various months of pregnancy.

Q2. Describe the changes that occur in ovaries and uterus in human female during the menstrual cycle.

Q3. Describe the role of pituitary and ovarian hormones during menstrual cycle in a human female.

Q4. Describe the menstrual cycle. Write about the hormones that regulate this cycle.

Q5. Explain in detail about menstrual cycle. Most Important

Q6. When and where are primary oocytes formed in human female ? Trace the development of these oocytes till ovulation.

Q7. Draw a well labelled diagrammatic sectional view of the female reproductive system and explain the structure of uterus.

Q8. Draw a well labelled diagram of human male reproductive system. Write about male sex accessory ducts.

Q9. Explain the role of accessory glands in human male reproductive system.

Q10. Describe the process of spermatogenesis. Most Important

Q11. Differentiate between oogenesis and spermatogenesis.

Q12. Describe the process of oogenesis.

Q13. Name the hormones involved in regulation of spermatogenesis.

Q14. Describe the process of spermatogenesis with the help of a well labelled diagram.

Q15. Describe the process of fertilization and implantation in human beings. Most Important

Q16. Trace the development of the zygote upto its implantation in the uterus.

Q17. Discuss parturition and lactation in human beings.

Q18. Write a note on parturition.

Q19. Explain the process of parturition in human female.

Q20. The yellowish fluid __________ secreted by mother during the initial days of lactation has abudant antibodies (IgA) to protect the infant.

Q21. Draw a well labelled sectional view of seminiferous tubule and explain its structure. Most Important

Q22. Draw a well labelled diagrammatic sectional view of mammary gland. Describe its structure. Most Important

Q23. Describe the structure of a sperm with the help of a well labelled diagram.
OR
Draw a well labelled diagram of human sperm.

Q24. What is spermiogenesis and spermiation ?

Q25. Write the specific location and the functions of the following cells human males : (a) Leydig cells (b) Sertoli cells, and (c) Primary spermatocytes

Q26. Name the inner and middle layers of human uterus and explain their roles.

Q27. Explain the events taking place at the time of fertilization of an ovum in a human female.

Q28. Write down the structure of fallopian tube.

Q29. Why is reproduction essential for organisms?

Q30. Name the hormone produced by interstitial cells.

Ans – androgens

Q31. Name various male accessory glands. Write their functions.

Q32. Draw a well labelled diagram of section view of ovary.

Ans – 

HBSE Class 12 Biology Chapter 3 – Reproductive Health Important Questions 2024

Q1. Describe Test Tube Baby Programme.

Q2. Describe various Intra-Uterine Devices (IUD).

Q3. Give an example of copper releasing IUD. How does it help in preventing pregnancy? Most Important

Q4. Name any hormone releasing IUDs.

Ans – Progestasert, LNG-20

Q5. Name one non-medicated IUDs.

Ans – CuT, Cu7, Multiload 375

Q6. Name oral contraceptive for females developed at CDRI Lucknow.

Ans – Saheli

Q7. Name the Institute where ‘Saheli’, an oral contraceptive tablet was developed ?

Ans – Central Drug Research Institute (CDRI) in Lucknow

Q8. Describe oral contraceptives.

Q9. What are the early symptoms of STD (Sexually Transmitted Disease)? What simple principles should be followed to prevent these diseases ?
OR
Write down early symptoms of STDs.
OR
What are the measures one has to take to prevent from contacting STDs?

Q10. Explain STDs.

Q11. Explain sterilisation method of contraception.
OR
Write about surgical methods of contraception.
OR
What is vasectomy?
OR
What is tubectomy?
OR
Sterilisation procedure in the male is called _________.

Ans – Surgical methods, also called sterilisation, are generally advised for the male/female partner as a terminal method to prevent any more pregnancies. Surgical intervention blocks gamete transport and thereby prevent conception. Sterilisation procedure in the male is called ‘vasectomy’ and that in the female, ‘tubectomy’.

Q12. Mention two main causes of population explosion in India.
OR
What are the major causes of population explosion in India?

Q13. Mention any four features of an ideal contraceptive.
OR
What should be the features of an ideal contraceptive ?

Ans – An ideal contraceptive should be user-friendly, easily available, effective and reversible with no or least side-effects. It also should in no way interfere with the sexual drive, desire and/or the sexual act of the user.

Q14. Write about the ill effects of wide spread use of various contraceptive methods.

Q15. What is amniocentesis ? What are its uses and misuses ?

Q16. Write a short note on GIFT.

Q17. What is GIFT technique ?

Q18. What is medical termination of pregnancy?

Q19. What is ZIFT technique?

Q20. Define reproductive health according to W. H. O.

Ans – According to the World Health Organisation (WHO), reproductive health means a total well-being in all aspects of reproduction, i.e., physical, emotional, behavioural and social.

Q21. Write full form of ICSI.
OR
Expand ICSI.

Ans – Intra cytoplasmic sperm injection

Q22. What is MTP and why it is used ?
OR
What is the need of MTP ?

Ans – Intentional or voluntary termination of pregnancy before full term is called medical termination of pregnancy (MTP). MTP is used to get rid of unwanted pregnancies. either due to casual unprotected intercourse or failure of the contraceptive used during coitus or rapes.

Q23. Write full form of “ART”.

Ans – assisted reproductive technologies

Q24. What complications could arise at later stage due to sexually transmitted disease?

Q25. Name various sexually transmitted diseases.

Q26. In which year programme of family planning were initiated in India?

Ans – 1951

HBSE Class 12 Biology Chapter 4 – Principles of Inheritance and Variation Important Questions 2024

Q1. What is dominance? Why are some alleles dominant and some recessive ?

Q2. What is co-dominance ? Explain with an example. Most Important

Q3. Which flower is a good example to study inheritance of flower colour in incomplete dominance ?

Q4. What is incomplete dominance and Co-dominance? Most Important

Q5. Explain law of dominance.

Q6. Describe various chromosomal disorders found in human beings. Most Important

Q7. Who gave chromosomal theory of inheritance?

Q8. Name the scientists who gave chromosomal theory of inheritance.

Q9. Describe the differences between the behaviour of chromosomes and the genes.

Q10. Total number of chromosomes in Down’s syndrome is __________

Q11. What are the causes and symptoms of Down’s syndrome?

Q12. Describe the sex determination in grasshopper and birds.

Q13. Explain any two autosomal genetic disorders with their symptoms.

Q14. Explain in detail about law of independent assortment.

Q15. Write about Klinefelter’s Syndrome.

Q16. Karyotype in Klinefelter syndrome is __________.

Q17. What is test cross? How can it decipher the heterozygosity of a plant?

Q18. Define test cross.

Q19. During his studies on genes in Drosophila that were sex linked. T. H. Morgan found F2 population phenotypic ratios deviated from expected 9 : 3 : 3 : 1. Explain the conclusion he arrived at.

Q20. Why was Drosophila melanogaster found suitable to Morgan for his studies?
OR
Why Drosophila melanogaster was found suitable for Morgan’s work ? Most Important

Q21. Why is pedigree analysis done in the study of human genetics ? State the conclusions that can be drawn from it.

Q22. Differentiate between homologous and analogous organs.

Q23. Are the wings of a bird and butterfly homologous organs or analogous organs ? Explain, and state the kind of evolution they represent.

Q24. Are the thorns of Bougainvillea and tendrills of Cucurbita homologous organs or analogous ? State the kind of evolution they represent.

Q25. What are homologous organs ? Give an example.

Q26. What are homologous structures in organisms ? State the kind of evolution they represent.

Q27. What are point mutation and frame shift mutation ? What do you mean by a mutagen ? Give any one example.

Q28. What are frame shift mutations ?

Q29. What were the reasons due to which Mendel’s work remained unrecognized till 1900 AD ?

Ans – Mendel published his work on inheritance of characters in 1865 but for several reasons, it remained unrecognised till 1900.

  1. Firstly, communication was not easy (as it is now) in those days and his work could not be widely publicised.
  2. Secondly, his concept of genes (or factors, in Mendel’s words) as stable and discrete units that controlled the expression of traits and, of the pair of alleles which did not ‘blend’ with each other, was not accepted by his contemporaries as an explanation for the apparently continuous variation seen in nature.
  3. Thirdly, Mendel’s approach of using mathematics to explain biological phenomena was totally new and unacceptable to many of the biologists of his time.

Q30. Describe the mechanism of sex determination in birds.
OR
How sex determination occurs in birds?

Q31. What is Aneuploidy and Polyploidy? Most Important
OR
What is aneuploidy ?
OR
What is polyploidy ?
OR
What is Aneuploidy ? Give two examples of it.

Q32. What is point mutation ? Give an example. Most Important

Q33. Write about phenylketonuria.

Q34. What is monosomy and trisomy? Give one example of each.
OR
What is trisomy ?

Q35. What is gene and allele ?

Q36. Name the scientist who coined the term ‘linkage’.

Ans – Morgan

Q37. What is mutagen?

Ans – There are many chemical and physical factors that induce mutations. These are referred to as mutagens.

Q38. Define Genotype.

Q39. What is Pedigree Analysis? How such an analysis can be useful?
OR
What is pedigree analysis?

Ans – An analysis of traits in a several of generations of a family is called the pedigree analysis. In the pedigree analysis the inheritance of a particular trait is represented in the family tree over generations.

Q40. Karyotype in Turner syndrome is __________

Q41. Define Monohybrid Cross.

Q42. Define Dihybrid Cross.

Q43. What are the cause and symptoms of Turner’s syndrome ?

Q44. Which are various copper releasing and hormone releasing IUDs?

Ans –  copper releasing IUDs (CuT, Cu7, Multiload 375) and the hormone releasing IUDs (Progestasert, LNG-20)

HBSE Class 12 Biology Chapter 5 – Molecular Basis of Inheritance Important Questions 2024

Q1. Who proved semi-conservative replication of DNA experimentally and how ? Explain.

Q2. Describe Meselson and Stahl’s experiment to prove semiconservative DNA replication.

Q3. State the aim and describe Meselson and Stahl’s experiment. 

Q4. Describe Hershey-Chase experiment to prove that DNA is the genetic material.

Q5. How did Hershey and Chase established that DNA is transferred from virus to bacteria ? Explain.

Q6. Explain in detail about double helix model of DNA.
OR
Write down the salient features of double helix structure of DNA.  Most Important

 

Q7. Describe the chemical structure of a polynucleotide chain of DNA.

Q8. Explain initiation, elongation and termination during transcription in bacterial cells.

Q9. Describe Frederick Griffith’s experiment on streptococcus pneumoniae. Discuss the conclusion he arrived at.

Q10. Describe the transformation principle proposed by Griffith. Most Important
OR
Describe transforming principle given in Griffith’s experiments.

Q11. How did Griffith explain the transformation of R-strain bacteria into S-strain ?

Q12. What is genetic code ? Write its salient features.
OR
Write down the salient features of Genetic Code.

Q13. What is dual function of genetic code AUG?

Q14. Describe the important goals of human genome project.
OR
Describe the salient features of Human Genome. Most Important

Q15. Describe translation in brief.
OR
Describe the process of Translation.

Q16. How does ribosome work in the process of translation ?

Q17. Describe the structure of transcription unit in detail.

Q18. Differentiate between prokaryotic transcription and eukaryotic transcription.

Q19. RNA polymerase binds to __________ site and initiates transcription.

Q20. In the medium where E. Coli was growing, lactose was added, which induced the lac operon. Then why does lac operon shut down some time after addition of lactose in the medium ?

Q21. Describe Lac-operon.

Q22. Explain, how Macleod, McCarty and Avery determined the biochemical nature of the molecules responsible for transforming R- strain bacteria into S-strain ?

Q23. Explain the mechanism of DNA replication. Highlight the role of enzymes in this process.

Q24. Why is DNA replication said to be semi-conservation?

Q25. What steps are included in DNA fingerprinting technique ?

Q26. Differentiate between promoter and terminator gene.

Q27. The terminator is located towards __________ end of the coding strand.

Q28. What are exons and introns ?

Q29. At which level the regulation of gene expression in Eukaryotes can be done?

Q30. How is the bacterial cell made competent to take up DNA ?

Q31. By which enzyme bacterial cell is broken ?

Q32. What is the cause of sickle cell anaemia? What happens to RBC in this disease? Most Important

Q33. What is Biochemical Oxygen Demand (BOD) ? What does it indicate ?
OR
What is BOD?

Ans – BOD refers to the amount of the oxygen that would be consumed if all the organic matter in one liter of water were oxidised by bacteria. The sewage water is treated till the BOD is reduced. The BOD test measures the rate of uptake of oxygen by micro-organisms in a sample of water and thus, indirectly, BOD is a measure of the organic matter present in the water.

Q34. Write a short note on nucleosome.

Ans – The negatively charged DNA is wrapped around the positively charged histone octamer to form a structure called nucleosome.

Q35. Name the scientist who named DNA as ‘Nuclein’.

Ans – Friedrich Meischer

Q36. What happen in splicing, capping and tailing?
OR
What is Capping ?
OR
What is Splicing?

Ans – it is subjected to a process called splicing where the introns are removed and exons are joined in a defined order. hnRNA undergoes additional processing called as capping and tailing. In capping an unusual nucleotide (methyl guanosine  triphosphate) is added to the 5′-end of hnRNA. In tailing, adenylate residues (200-300) are added at 3′-end in a template independent manner. It is the fully processed hnRNA, now called mRNA.

Q37. Name the scientific name of fruit fly. Most Important

Ans – Drosophila

Q38. What are the goals of HGP?

Ans – Goals of HGP Some of the important goals of HGP were as follows:
(i) Identify all the approximately 20,000-25,000 genes in human DNA;
(ii) Determine the sequences of the 3 billion chemical base pairs that make up human DNA;
(iiii) Store this information in databases;
(iv) Improve tools for data analysis;
(v) Transfer related technologies to other sectors, such as industries;
(vi) Address the ethical, legal, and social issues (ELSI) that may arise from the project.

Q39. Name the scientist who proposed Transformation experiment.

Ans – Frederick Griffith

Q40. Write down the full form of ELSI.

Ans – ethical, legal, and social issues

Q41. Promotor is said to be located towards __________ end of the structural gene.

Ans – 5′

Q42. Write down difference between ‘DNAs’ and ‘DNase’.

Q43. Write down the full form of EST.

Ans – Expressed Sequence Tags

Q44. In ________ an unusual nucleotide (methyl guanosine triphosphate) is added to 5′ end of hn-RNA.

Ans – capping

Q45. What is Euchromatin ?

Ans – Euchromatin is said to be transcriptionally active chromatin, whereas heterochromatin is inactive.

Q46. Write down the full form of UTR.

Ans – untranslated regions

Q47. In __________adenylate residue (200-300) are added at 3′ end in a template In independent manner.

Ans – Tailing

Q48. Discontinuously synthesized fragments are joined by enzyme __________

Ans – DNA ligase

Q49. What is Heterochromatin ?

Ans – The chromatin that is more densely packed and stains dark are called as Heterochromatin.

Q50. Why is DNA chemically less reactive and structurally more stable when compared to RNA ?

Q51. Who gave unequivocal experimental proof that DNA is the genetic material ? Describe their experiment.

HBSE Class 12 Biology Chapter 6 – Evolution Important Questions 2024

Q1. Write about Miller’s experiment. Most Important

Q2. Write down the features of Homo habilis, Homo erectus and Neanderthal man.
OR
Write down the characteristics of Homo habilis and Homo erectus.

Q3. What are the three connotations of theory of special creation ?

Q4. Explain natural selection with an example of moth.

Q5. Describe mechanism of evolution.

Q6. What are analogous structures in organisms ? State the kind of evolution they represent.

Q7. Write briefly about chemical theory of evolution.

Q8. Write about Hugo de Vries theory of evolution. How does it differ from Darwin view? Most Important

Q9. Write about Lamarck Theory of Evolution.

Ans – A French naturalist Lamarck had said that evolution of life forms had occurred but driven by use and disuse of organs. He gave the examples of Giraffes who in an attempt to forage leaves on tall trees had to adapt by elongation of their necks. As they passed on this acquired character of elongated neck to succeeding generations, Giraffes, slowly, over the years, came to acquire long necks.

Q10. Write down the examples of evolution by anthropogenic action.

Q11. List the factors affecting Hardy-Weinberg equilibrium.

Q12. Which five factors are known to affect Hardy-Weinberg Equilibrium ?

Q13. What is adaptive radiation? Give an example.

Ans – This process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography (habitats) is called adaptive radiation. Example – Australian marsupials, Darwin’s finches

Q14. Which was the biggest land Dinosaurs ?

Ans – Tyrannosaurus rex with 20 feet in height.

Q15. First mammals were like _________

Ans – shrews

Q16. Name two primates which existed about 15 mya. Write their characters.

Ans – About 15 mya, primates called Dryopithecus and Ramapithecus were existing. They were hairy and walked like gorillas and chimpanzees. Ramapithecus was more man-like while Dryopithecus was more ape-like.

HBSE Class 12 Biology Chapter 7 – Human Health and Disease Important Questions 2024

Q1. Describe various Cannabinoid drugs.

Q2. Explain the treatment of adenosine deaminase deficiency by genetically engineered lymphocytes. Why is this treatment not permanent ?

Q3. Write about the treatment of adenosine deaminase deficiency by genetically engineered lymphocytes.

Q4. __________ lymphocytes produce antibodies in human.

Ans – B

Q5. What is Allergy ? How does it take place & what are its symptoms ? Most Important

Q6. What is Allergy? What are the chemicals released from mast cells for allergy? Write down the symptoms of allergic reactions.

Q7. Write the name of causative organism and symptoms of disease Pneumonia, How does a healthy person acquire this infection ? Most Important
OR
Write name of causative organism, symptoms & mode of transmission of Pneumonia.

Q8. What are the harmful effects of using Tobacco ? Most Important

Q9. Describe the effects of smoking and chewing of tobacco.

Q10. Write about opioids drugs. Most Important

Ans – Opioids are the drugs, which bind to specific opioid receptors present in our central nervous system and gastrointestinal tract.

Q11. What is “MALT” ?
OR
Write full form of MALT.

Ans – There is lymphoid tissue also located within the lining of the major tracts (respiratory, digestive and urogenital tracts) called mucosa associated lymphoid tissue (MALT).

Q12. Why HIV is called Retrovirus ?

Ans – AIDS is caused by the Human Immuno deficiency Virus (HIV), a member of a group of viruses called retrovirus, which have an envelope enclosing the RNA genome.

Q13. Expand “CMI”.

Ans – cell-mediated immunity

Q14. Describe the effects of drug/alcohol abuse.

Q15. Describe the life cycle of Plasmodium.

Ans – Plasmodium enters the human body as sporozoites (infectious form) through the bite of infected female Anopheles mosquito. The parasites initially multiply within the liver cells and then attack the red blood cells (RBCs) resulting in their rupture. The rupture of RBCs is associated with release of a toxic substance, haemozoin, which is responsible for the chill
and high fever recurring every three to four days. When a female Anopheles mosquito bites an infected person, these parasites enter the mosquito’s body and undergo further development. The parasites multiply within them to form sporozoites that are stored in their salivary glands. When these mosquitoes bite a human, the sporozoites are introduced into his/ her body, thereby initiating the events mentioned above.

Q16. Write full form of NACO.

Ans – National AIDS Control Organisation

Q17. What is Innate Immunity? Write down its various barriers. Most Important
OR
Explain barriers of innate immunity.
OR
What are the physical and cellular barriers of innate immunity?
OR
What are cytokine barriers?

Ans – Innate immunity is non-specific type of defence, that is present at the time of birth. This is accomplished by providing different types of barriers to the entry of the foreign agents into our body. Innate immunity consist of four types of barriers. These are —

(i) Physical barriers : Skin on our body is the main barrier which prevents entry of the micro-organisms. Mucus coating of the epithelium lining the respiratory, gastrointestinal and urogenital tracts also help in trapping microbes entering our body.

(ii) Physiological barriers : Acid in the stomach, saliva in the mouth, tears from eyes–all prevent microbial growth.

(iii) Cellular barriers : Certain types of leukocytes (WBC) of our body like polymorpho-nuclear leukocytes (PMNL-neutrophils) and monocytes and natural killer (type of lymphocytes) in the blood as well as macrophages in tissues can phagocytose and destroy microbes.

(iv) Cytokine barriers : Virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection.

Q18. Write about causes and treatment of Cancer.
OR
Write a note on treatment of cancer.

Q19. Name the type of cells that AIDS virus first enters into after getting inside the human body. Explain the sequence of events that virus undergoes within these cells to increase their Progeny.

Q20. Which diagnostic test is widely used to detect AIDS? Most Important

Ans – A widely used diagnostic test for AIDS is enzyme linked immuno-sorbent assay (ELISA)

Q21. What is contact inhibition?

Ans – Normal cells show a property called contact inhibition by virtue of which contact with other cells inhibits their uncontrolled growth.

Q22. What is contact inhibition in the normal cells of the body? What are the consequences, when this property is lost by these cells ?

Q23. Give the scientific name of the malarial parasite that causes malignant malaria in human Mention the symptoms of malaria disease.

Ans – Plasmodium falciparum causes malignant malaria in human. Symptoms of this disease include constipation, abdominal pain and cramps, stools with excess mucous and blood clots.

Q24. A patient is down with typhoid fever. List the symptoms that confirm this infection. Name the causative pathogen.

Ans – Salmonella typhi is a pathogenic bacterium which causes typhoid fever in human beings Sustained high fever (39° to 40°C), weakness, stomach pain, constipation, headache and loss of appetite are some of the common symptoms of this disease.

Q25. By which test typhoid fever could be confirmed? Most Important

Ans – Widal Test

Q26. Name causative organism of Typhoid.  Most Important

Ans – Salmonella typhi

Q27. What are the various public health measures, which you would suggest as safeguard against infectious diseases?

Q28. Name the plant from which Cocaine is obtained.

Ans – Erythroxylum coca

Q29. Name causative organism of Pneumonia.

Ans – Bacteria like Streptococcus pneumoniae and Haemophilus influenzae are responsible for the disease pneumonia

Q30. Name causative organism of Elephantiasis.

Ans – Wuchereria, the filarial worms

Q31. What is ‘interferon ?

Ans – Virus-infected cells secrete proteins called interferons

Q32. Name causative organism of Amoebiasis.

Ans – Entamoeba histolytica is a protozoan parasite in the large intestine of human which causes amoebiasis.

Q33. What is autoimmune disease? Give an example.

Ans – sometimes, due to genetic and other unknown reasons, the body attacks self-cells. This results in damage to the body and is called auto-immune disease. Rheumatoid arthritis which affects many people in our society is an auto-immune disease.

Q34. Define Disease.

Ans – When the functioning of one or more organs or systems of the body is adversely affected, characterised by appearance of various signs and symptoms, we say, we have a disease.

Q35. What is Active Immunity?

Q36. What is passive immunity ?

Ans – When ready-made antibodies are directly given to protect the body against foreign agents, it is called passive immunity.

Q37. What are secondary lymphoid organs? Name various secondary lymphoid organs.

Q38. What are Lymphoid Organs ?

Q39. Define Health.

Q40. What are the primary lymphoid organs ? Name various primary lymphoid organs.

 

HBSE Class 12 Biology Chapter 8 – Microbes in Human Welfare Important Questions 2024

Q1. How microbes are useful as bio-control agents? Explain.

Q2. How does microbial biocontrol agents control butterfly caterpillars?

Q3. Which baculoviruses are used as biological control agents ?

Q4. State the medicinal value and the bioactive molecules produced by Streptococcus, Monascus and Trichoderma.

Q5. How Trichoderma polysporum is useful for human beings ? Most Important

Q6. What are methanogens? How do they help to generate biogas?

Q7. Give an example of Methanogen.

Q8. How are flocs produced in the secondary treatment plant of Sewage ? Explain their role.
OR
Write note on secondary treatment in sewage treatment plant.

Q9. What are Baculoviruses? Explain their role in bio-control of pests.

Q10. Write down the role of Baculoviruses in biological control. Most Important

Q11. Draw a well labelled diagram of a typical biogas plant.

Q12. Describe structure of Biogas plant. Write its functions.

Q13. What is the role of microbes in the production of bioactive molecules ?

Q14. Which microbes are used in the production of bioactive molecules ? Write their uses.

Q15. What is mycorrhiza ? What are its uses? Most Important
OR
What is mycorrhiza ? Write its advantages.

Q16. Write down the role of microbes for the production of fermented beverages.

Q17. What is flocs ? Most Important

Q18. What is Antibiotic? Most Important

Q19. Statins produced by Yeast __________ have been commercialized as blood cholesterol lowering agent.

Ans – Monascus purpureus

Q20. Cyclosporin-A is used as an __________ agent.

Ans – immunosuppressive

Q21. Clostridium butylicum produces a acid called __________.

Ans – butyric acid

Q22. Explain the role of cyanobacteria to enrich the fertility of soil.

Q23. Write about primary treatment of sewage water.

Q24. Write the full form of IARI.

Ans – Indian Agricultural Research Institute

Q25. Write the full form of SCP.

Ans – Single cell protein

 

Q26. Which microbe is used for commercial production of citric acid?

Ans – Aspergillus niger (a fungus)

Q27. Name the bacteria which can fix atmospheric nitrogen while free living in the soil.
OR
Write about the bacteria which fix atmospheric nitrogen.

Ans – Azospirillum and Azotobacter

Q28. Alexander Fleming was working on which bacteria when he discovered Penicillin ?

 Ans – Staphylococci

Q29. Which yeast is used for commercial production of Ethanol ?
OR
What is the scientific name of Yeast ?

Ans – Saccharomyces cerevisiae

Q30. Large holes in “Swiss Cheese” are due to production of a large amount of __________ by a bacterium named Propionibacterium Shermanii.

Ans – CO2

Q31. LAB is useful in production of household articles/products. How & when item it produces ?
OR
In which food lactic acid bacteria are present ? Write their useful applications.

Ans – Micro-organisms such as Lactobacillus and others commonly called lactic acid bacteria (LAB) grow in milk and convert it to curd. During growth, the LAB produce acids that coagulate and partially digest the milk proteins. A small amount of curd added to the fresh milk as inoculum or starter contain millions of LAB, which at suitable temperatures multiply, thus converting milk to curd, which also improves its nutritional quality by increasing vitamin B12.

 

HBSE Class 12 Biology Chapter 9 – Biotechnology : Principles and Processes Important Questions 2024

Q1. Explain PCR.

Q2. What are the various steps of PCR? From which bacteria thermostable DNA polymerase is isolated ?

Q3. Write down full form of PCR. 

Ans – Polymerase Chain Reaction

Q4. PCR consists of 3 steps: Denaturation, __________ & extension of primers.

Ans – Primer annealing

Q5. What is EcoRI ? Write the palindromic nucleotide sequence recognized by it. State the role of EcoRI in biotechnology.
OR
What is EcoRI ?

Q6. What is Plasmid ?

Q7. Why is it difficult for DNA to pass through cell membranes ? How is a bacterial cell made competent to take up DNA (plasmid)?

Q8. How are the desired DNA sequences used in biotechnology cut ? Explain the technique used to separate the cut fragments.
OR
Name the technique by which DNA fragments can be separated. Most Important

Q9. How can DNA be cut at specific locations ? Most Important

Q10. The separated bands of DNA are cut out from the agarose gel and extracted from the gel piece. This step is known as __________.

Ans – Elution

Q11. What is Biotechnology ? Which two core techniques contributed in the development of modern biotechnology ?

Ans – Biotechnology deals with techniques of using live organisms or enzymes from organisms to produce products
and processes useful to humans.

The two core techniques of modern biotechnology are :

(i) Genetic engineering : Techniques to alter the chemistry of genetic material (DNA and RNA), to introduce these into host organisms and thus change the phenotype of the host organism.

(ii) Bioprocess engineering: Maintenance of sterile (microbial contamination-free) ambience in chemical engineering processes to enable growth of only the desired microbe/eukaryotic cell in large quantities for the manufacture of biotechnological products like antibiotics, vaccines, enzymes, etc.

Q12. Name the bacteria from which thermostat DNA polymerase is isolated ?

Ans – Thermus aquaticus

Q13. How is a bacteria cell made competent to take up DNA ? 

Ans – In order to force bacteria to take up the plasmid, the bacterial cells must first be made ‘competent’ to take up DNA. This is done by treating them with a specific concentration of a divalent cation, such as calcium, which increases the efficiency with which DNA enters the bacterium through pores in its cell wall. Recombinant DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice, followed by placing them briefly at 420C (heat shock), and then putting them back on ice. This enables the bacteria to take up the recombinant DNA.

Q14. Name the selectable markers in the cloning vector pBR 322 ? Mention the role they play.

Q15. What are restriction enzymes ? Write the convention for naming such enzymes with an example.

Q16. What are restriction enzymes? How they are useful ?

Q17. Till today we know more than __________ restriction enzymes that have been isolated from over 230 strains of bacteria each of which recognize different recognition sequences.

Ans – 900

Q18. Write note on gel electrophoresis.

Ans – The cutting of DNA by restriction endonucleases results in the fragments of DNA. These fragments can be separated by a technique known as gel electrophoresis. Since DNA fragments are negatively charged molecules they can be separated by forcing them to move towards the anode under an electric field through a medium/matrix. Nowadays the most commonly used matrix is agarose which is a natural polymer extracted from sea weeds.

Q19. Write down various research areas of biotechnology. Most Important

Q20. What are the methods to introduce alien DNA into host plant and animal cells?

Q21. What are the functions of Exonucleases and Endonucleases ?
OR
What are Exonucleases and Endonucleases ?
OR
Explain the role of Exonuclease.
OR
What is the role of Endonuclease ?

Q22. What are palindromes ? Explain with an example.
OR
What is Palindrome in DNA?

Q23. What is the microinjection and biolistics method to introduce the recombinant DNA into the host cells ?

Q24. Write about ‘bioreactors’.

Q25. Write about origin of replication required to facilitate cloning into a vector.

Ans – This is a sequence from where replication starts and any piece of DNA when linked to this sequence can be made to replicate within the host cells. This sequence is also responsible for controlling the copy number of the linked DNA. So,
if one wants to recover many copies of the target DNA it should be cloned in a vector whose origin support high copy number.

Q26. What is clone ?

Q27. Write full form of “Ori”.

Ans – Origin of replication

Q28. What is insertional inactivation. Most Important

Ans – A recombinant DNA is inserted within the coding sequence of an enzyme, β-galactosidase. This results into inactivation of the gene for synthesis of this enzyme, which is referred to as insertional inactivation.

Q29. Write down full form of P.C.R.

Ans – Polymerase chain reaction

Q30. Explain the method of isolation of Genetic material (DNA).

Q31. Write full form of EFB.

Ans – European Federation of Biotechnology

Q32. Draw a well labelled diagram of E. Coli cloning vector pBR322 showing restriction sites and antibiotic resistance genes. Most Important

HBSE Class 12 Biology Chapter 10 – Biotechnology and its Applications Important Questions 2024

Q1. What is RNA interference technique of cellular defence ? Explain with an example. Most Important

Q2. How does RNA interference helps in developing resistance in tobacco plant against nematode infection?

Q3. What is RNA interference?

Q4. What is gene therapy? Illustrate using the example of adenosine deaminase (ADA) deficiency. Most Important

Q5. What is gene therapy ? Name the first clinical case, where it was used.

Q6. What is Gene Therapy? Most Important

Q7. How did an American Company Eli Lilly use the knowledge of rDNA technology to produce human insulin ?

Q8. What are transgenic animals? Explain the role of transgenic animals in biological products. Most Important
OR
Explain the role of transgenic animals in biological products.
OR
Write a note on biological products obtained from transgenic animals.

Q9. What are transgenic animals? Explain their role in study of disease.

Q10. What is the role of transgenic animals in normal physiology and development?

Q11. For testing of safety of Polio vaccine which transgenic animal is used? 

Ans – Transgenic mice

Q12. What are the advantages of production of genetically modified crops ?
OR
What are the advantages of genetically modified plants?

Q13. What are the basic steps in genetically modifying an organism ?

Q14. Name the nematode which infects the roots of tobacco plant.

Q15. What are biotechnological applications in molecular diagnosis?
OR
How is biotechnology helpful in molecular diagnosis ?

Q16. Write a note on Bt-cotton.

Q17. Why are the plants raised through micro-propagation termed as somaclones? Mention two advantages of this technique.

Q18. Explain GEAC and mention the responsibilities of this organization set- up by the Indian Government.

Q19. What is GEAC. Write its role.
OR
Write full form of GEAC.

Ans – The Indian Government has set up organisations such as GEAC (Genetic Engineering Approval Committee), which will make decisions regarding the validity of GM research and the safety of introducing GM-organisms for public services.

Q20. Why does the Bt toxin not kill the bacterium that produces it but kills the insect that ingest it ? Explain. Most Important

Q21. Write the name of gene which code Bt toxin. Name various types of genes which produce such toxin.

Q22. Bt toxin is produced by a bacterium __________

Ans – Bacillus thuringiensis

Q23. What are somatic hybrids ? Give an example.

Q24. Name the first transgenic cow. What is the advantage of its milk over than natural cow milk?

Ans – In 1997, the first transgenic cow, Rosie, produced human protein-enriched milk (2.4 grams per litre). The milk contained the human alpha-lactalbumin and was nutritionally a more balanced product for human babies than natural cow-milk.

Q25. What is biopiracy? Most Important

Ans – Biopiracy is the term used to refer to the use of bio-resources by multinational companies and other organisations without proper authorisation from the countries and people concerned without compensatory payment.

Q26. The protein encoded by which gene controls corn borer ?

Ans – cryIAb

Q27. The polypeptide chains of insulin are linked by which bonds ?

Ans – disulphide bridges

Q28. How many polypeptide chains are present in Pro-insulin?

Ans – Insulin consists of two short polypeptide chains: chain A and chain B.

Q29. ELISA is based on which principle?

Ans – ELISA is based on the principle of antigen-antibody interaction.

Q30. Write full form of ELISA.

Ans – Enzyme Linked Immuno-sorbent Assay

Q31. How are GM plants useful?

Ans – GM plants have been useful in many ways. Genetic modification has:
(i) made crops more tolerant to abiotic stresses (cold, drought, salt, heat).
(ii) reduced reliance on chemical pesticides (pest-resistant crops).
(iii) helped to reduce post harvest losses.
(iv) increased efficiency of mineral usage by plants (this prevents early exhaustion of fertility of soil).
(v) enhanced nutritional value of food, e.g., golden rice, i.e., Vitamin ‘A’ enriched rice

Q32. Name the American Company who used the rDNA techniques to produce Human Insulin.
OR
In 1983, which American company prepared insulin?

Ans – Eli Lilly

Q33. Expand GMO.

Ans – Genetically Modified Organisms

Q34. Write full form of ‘ADA’ gene.

Ans – adenosine deaminase

Q35. Describe the structure of Pro insulin and Mature insulin. How is Genetically Engineered Insulin developed ?

Q36. What are Cry proteins ? Name the organism that produce it. How has man exploited this protein for his benefit ?

HBSE Class 12 Biology Chapter 11 – Organisms and Populations Important Questions 2024

Q1. What is commensalism ? Give one example of this population interaction from plants and one from animals.

Q2. Explain commensalism with an example. 

Ans – The interaction where one species is benefitted and the other is neither benefitted nor harmed is called commensalism. Example – the interaction between sea anemone that has stinging tentacles and the clown fish that lives among them.

Q3. What is amensalism and commensalism? Most Important

Ans – The interaction where one species is benefitted and the other is neither benefitted nor harmed is called  commensalism. In amensalism on the other hand one species is harmed whereas the other is unaffected.

Q4. What is mutualism? Give any two example of this population interaction.

Q5. What is Mutualism? Most Important

Ans – This interaction confers benefits on both the interacting species. Lichens represent an intimate mutualistic relationship between a fungus and photosynthesising algae or cyanobacteria.

Q6. Write about brood parasitism.

Q7. Define Natality.

Ans – Natality refers to the number of births during a given period in the population that are added to the initial density.

Q8. What is Predation?

Ans – predation is described as nature’s way of transferring to higher trophic levels the energy fixed by plants.

Q9. Define Mortality.

Ans – Mortality is the number of deaths in the population during a given period.

Q10. Define Immigration.

Ans – Immigration is the number of individuals of the same species that have come into the habitat from elsewhere during the time period under consideration.

Q11. Write about important defence mechanisms in plants against herbivory.

HBSE Class 12 Biology Chapter 12 – Ecosystem Important Questions 2024

Q1. Discuss importance of species diversity to the ecosystem. Most Important

Q2. What is stratification in an ecosystem ?

Q3. Write important features of a sedimentary cycle in an ecosystem.

Q4. What is standing crop in an ecosystem?

Q5. What is secondary productivity in an ecosystem?

Q6. What is Decomposition ? What are the climatic factors that regulate it?

Q7. How do climatic factors affect process of decomposition in ecosystem ? Explain.

Q8. What is decomposition ? Write about effect of temperature and moisture on this process. Most Important

Q9. Write about the factors which control rate of decomposition. Most Important

Q10. What is meant by productivity ? Differentiate between gross primary productivity and net primary productivity. Most Important

Q11. What is secondary productivity?

Q12. What are the limitations of Ecological pyramids ?

Q13. Describe abiotic and biotic components of a pond.

Q14. Why is pyramid of biomass in sea generally inverted? Explain.

Q15. What is the theory of spontaneous generation ? Name the scientist who dismissed it.
OR
Name the scientist who dismissed the theory of spontaneous generation.

Q16. Differentiate between food chain and food web.

Q17. What is detritus food chain? How do they meet their energy requirement ?

Q18. Describe the pyramid of number.

HBSE Class 12 Biology Chapter 13 – Biodiversity and Conservation Important Questions 2024

Q1. Describe species area relationship pattern of biodiversity.

Q2. How do we conserve biodiversity ?

Q3. Write about the biodiversity in Tropical Amazonian rain forest in South America.

Q4. Describe the broadly utilarian argument for conserving biodiversity.

Q5. What are sacred groves ? Where are they found ? What is their role in biodiversity?
OR
Explain the role of sacred groves in conservation of biodiversity.
OR
What are sacred groves ?
OR
What are sacred groves ? Write down their role in conservation. Most Important

Q6. Explain three major causes of biodiversity loss.

Q7. What are the consequences of loss of  biodiversity in a region ?

Q8. Describe any three techniques where the principle of ex-situ conservation of biodiversity has been employed.

Q9. Name the socio-biologist who popularized the term biodiversity. Identify the level of biodiversity represented by 50,000 strains of rice in India.

Q10. State any two uses of biodiversity in agriculture.

Q11. State any two uses of biodiversity in industrial products.

Q12. How does over-exploitation and co-extinctions cause biodiversity loss?

Q13. Explain the reasons/causes of Biodiversity loss. Most Important

Q14. Why should we conserve biodiversity ? Most Important

Q15. Where was the Earth Summit held in 1992 ? Most Important

Ans – Rio de Janeiro

Q16. What is the impact of loss of Biodiversity ?

Q17. Describe ex situ conservation of biodiversity.

 

Q18. Explain with examples how do habitat loss and fragmentation cause extinction of plants and animals?

Q19. Give three hypotheses for explaining why tropics show greatest levels of species richness. Most Important

Q20. What is so special about tropics that might accounts for their great diversity?

Q21. What is Endemism? Most Important

Ans – species confined to that region and not found anywhere else is called endemism.

Q22. Where was the World Summit of Sustainable Development held in 2002 ? Most Important

Ans – Johannesburg, South Africa

Q23. There and many animals that have become extinct in the wild, but continue to be maintained in zoological parks.

Q24. Explain any two other ways which help in this type of conservation.

Q25. Explain, why are very small animals rarely found in polar regions? Most Important

Q26. What is ex-situ conservation ?

Q27. Explain with examples, how do alien species invasion cause extinction of indigenous species ?

 

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