Question
Write a short note on embryo development.###With a labeled diagram discuss stages in embryo development in a dicot.
✓
Answer
Embryo develops at the micropylar end of the embryo sac where the zygote is situated. 
→ Most zygotes divide only after certain amount of endosperm is formed. This is an adaptation to provide assured nutrition to the developing embryo.
→ Though the seeds differ greatly, the early stages of embryo development (embryogeny) are similar in both monocotyledons and dicotyledons.
→ Figure depicts the stages of embryogeny in a dicotyledonous embryo. The zygote gives rise to the proembryo and subsequently to the globular, heart-shaped and mature embryo.
Dicotyledonous embryo:
→ A typical dicotyledonous embryo, consists of an embryonal axis and two cotyledons.
(i) Epicotyl: The portion of embryonal axis above
the level of cotyledons is the Epicotyl, which terminates with the plumule or stem tip.
(ii) Hypocotyl: The cylindrical portion below the level of cotyledons is Hypocotyl that terminates at its lower end in the radicle or root tip. The root tip is covered with a root cap.
Monocotyledonous embryo :
→ Embryos of monocotyledons possess only one cotyledon.
(i) Scutellum: In the grass family the cotyledon is called scutellum that is situated towards one side (lateral) of the embryonal axis.
(ii) Coleorrhiza: At its lower end, the embryonal axis has the radical and root cap enclosed in an undifferentiated sheath called Coleorrhiza.
(iii) Coleoptile: 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, the Coleoptile.
→ Most zygotes divide only after certain amount of endosperm is formed. This is an adaptation to provide assured nutrition to the developing embryo.
→ Though the seeds differ greatly, the early stages of embryo development (embryogeny) are similar in both monocotyledons and dicotyledons.
→ Figure depicts the stages of embryogeny in a dicotyledonous embryo. The zygote gives rise to the proembryo and subsequently to the globular, heart-shaped and mature embryo.
Dicotyledonous embryo:
→ A typical dicotyledonous embryo, consists of an embryonal axis and two cotyledons.
(i) Epicotyl: The portion of embryonal axis above
the level of cotyledons is the Epicotyl, which terminates with the plumule or stem tip.
(ii) Hypocotyl: The cylindrical portion below the level of cotyledons is Hypocotyl that terminates at its lower end in the radicle or root tip. The root tip is covered with a root cap.
Monocotyledonous embryo :
→ Embryos of monocotyledons possess only one cotyledon.
(i) Scutellum: In the grass family the cotyledon is called scutellum that is situated towards one side (lateral) of the embryonal axis.
(ii) Coleorrhiza: At its lower end, the embryonal axis has the radical and root cap enclosed in an undifferentiated sheath called Coleorrhiza.
(iii) Coleoptile: 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, the Coleoptile.
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Read the following and answer any four questions from (i) to (v) given below: X and Y are communicable diseases, whereas Wand Z are non-communicable diseases.X is transmitted through vectors whereas Y is transmitted through droplet infection. Wis caused due to a hormone deficiency, whereas Z is a degenerative disease. Based on the above information, answer the following questions.
- Identify W, X, Y and Z.
| | W | X | Y | Z |
| (a) | Coronary artery disease | Cholera | Chikungunya | Chikungunya |
| (b) | Diabetes | Malaria | Rhinitis | Alzheimer's disease |
| (c) | Alzheimer's disease | AIDS | Shigella | Plague |
| (d) | Gonorrhea | Diphtheria | Pertussis | Anthrax |
- Select the correct statement.
- If X is sleeping sickness then its vector is Leishrnania.
- If Y is diphtheria then it is caused by Bacillus anthracis.
- If W is hypothyroidism then it is caused by deficiency of thyroxine hormone.
- If Z is myocardial infarction then patient develops acute rheumatic fever, joint pain and throat infection.
- If X and Y both are usual diseases then which of the following holds true?
- X could be dengue caused by flavivirus and Y could be AIDS caused by HIV.
- X could be chikungunya whereas Y could be rhinitis.
- X could be hepatitis whereas Y could be rabies.
- X could be chicken pox caused by Va rice/la zoster virus whereas Y could be yellow fever caused by flavivirus
- If X and Y both are bacterial diseases then select the correct match from the following.
- X- Bubonic plague-Yersinia pestis
- Y-Leprosy- Mycobacteriurn leprae
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- Y-Botulism-Clostridiurn botulinum
- Assertion: Communicable diseases could be contagious or non-contagious.
Reason: Diseases that spread through vectors are non-contagious disease.
- Both assertion and reason are true, and reason is the correct explanation of assertion.
- Both assertion and reason are true, but reason is not the correct explanation of assertion.
- Assertion is true, but reason is false.
- Both assertion and reason are false.
Read the following text carefully and answer the questions that follow:
Transgenic animals can serve as factories that in some cases, may produce large amounts of proteins more efficiently. Transgenic mice have been engineered to express human antibodies by introducing a large segment of human DNA encoding human immunoglobulin genes. In transgenic large animals such as cows or sheep proteins of pharmaceutical value can be produced in large quantities in milk which is later purified. Transgenes can be used to alter many phenotypic properties including growth rate, fat composition, milk production, hair texture, etc.
i. In transgenic animals, i.e. cow and sheep proteins of pharmaceutical value are produced in large quantities in which gland. (1)
ii. Why is mouse the most preferred animal for studies on gene transfer? (1)
iii. Why does the production of transgenic animals take place? (2)
OR
Assertion (A): Transgenic mice have been engineered to express human antibodies. (2)
Reason (R): Large segments of human DNA encoding human immunoglobulin have been transferred to mice.
a. Both A and R are true and R is the correct explanation of A.
b. Both A and R are true but R is not the correct explanation of A.
c. A is true but R is false.
d. A is false but R is true.
Transgenic animals can serve as factories that in some cases, may produce large amounts of proteins more efficiently. Transgenic mice have been engineered to express human antibodies by introducing a large segment of human DNA encoding human immunoglobulin genes. In transgenic large animals such as cows or sheep proteins of pharmaceutical value can be produced in large quantities in milk which is later purified. Transgenes can be used to alter many phenotypic properties including growth rate, fat composition, milk production, hair texture, etc.
i. In transgenic animals, i.e. cow and sheep proteins of pharmaceutical value are produced in large quantities in which gland. (1)
ii. Why is mouse the most preferred animal for studies on gene transfer? (1)
iii. Why does the production of transgenic animals take place? (2)
OR
Assertion (A): Transgenic mice have been engineered to express human antibodies. (2)
Reason (R): Large segments of human DNA encoding human immunoglobulin have been transferred to mice.
a. Both A and R are true and R is the correct explanation of A.
b. Both A and R are true but R is not the correct explanation of A.
c. A is true but R is false.
d. A is false but R is true.
Read the following and answer any four questions from (i) to (v) given below:
The foundations of recombinant DNA (rDNA) were laid by the discovery of restriction enzymes. These enzymes are present in many bacterias where they function as a part of their defense mechanism called the Restriction Modification system (RM system). Molecular basis of this system was explained first by Werner Arber in 1962. The Restriction Modification system consists of two components:
The foundations of recombinant DNA (rDNA) were laid by the discovery of restriction enzymes. These enzymes are present in many bacterias where they function as a part of their defense mechanism called the Restriction Modification system (RM system). Molecular basis of this system was explained first by Werner Arber in 1962. The Restriction Modification system consists of two components:
- A restriction enzyme (called restriction endonuclease) identifies the introduced foreign DNA and cuts it into pieces.
- The second component is a modification enzyme (methylase) that adds a methyl group to DNA at specific site to protect it from the restriction enzyme cleavage.
- Restriction endonucleases are enzymes present in ________ where they function as a part of _______ mechanism.
- (i) bacteria (ii) digestive
- (i) protists (ii) transcription
- (i) plant cells (ii) replication
- (i) prokaryotes (ii) defence
- Which of the following statements regarding modification enzyme is correct?
- It adds methyl group to one or two bases usually within the host DNA sequence to protect it from the restriction enzyme.
- It adds ethyl group to one or two bases usually within the sequence recognised by the restriction enzymes.
- It adds methyl group to only one of bases within the foreign DNA sequence that is recognised by the restriction enzymes.
- None of these.
- Which of the following is a type II restriction enzyme?
- Alu I
- EcoR I
- BamH I
- All of these.
- Which of the following is the first discovered restriction endonuclease?
- Sal I
- EcoR I
- Hind II
- EcoR II
- Components of Restriction Modification System include?
- Restriction enzyme.
- Modification enzyme.
- Lysing enzyme.
- Both (a) and (b).
Read the following and answer any four questions from (i) to (v) given below:
The pollen grains or microspores are the male reproductive bodies of a flower and are contained in the pollen sac or microsporangia. Each pollen grain consists of a single microscopic cell, possessing two coats: the exine and the in tine. The exine of a pollen grain is made of chemically stable material. Because of this, pollen grains are often very well preserved for thousands of years in soil and sediments.
The pollen grains or microspores are the male reproductive bodies of a flower and are contained in the pollen sac or microsporangia. Each pollen grain consists of a single microscopic cell, possessing two coats: the exine and the in tine. The exine of a pollen grain is made of chemically stable material. Because of this, pollen grains are often very well preserved for thousands of years in soil and sediments.
- One of the most resistant biological material present in the exine of pollen grain is:
- Pectocellulose.
- Sporopollenin.
- Suberin.
- Cellulose.
- The exine possesses one or more thin places known as:
- Raphe.
- Germ pores.
- Hilum.
- Endothecium.
- What is the function of germ pore?
- Emergence of radicle.
- Absorption of water for seed germination.
- Initiation of pollen tube.
- All of these.
- What is the key advantage to the plant for having such strong pollen grain walls?
- It protects the vital genetic material in the pollen grain.
- It allows pollen to serve as a valuable fossil record for the study of ancient plants.
- It prevents the pollen tube from growing out before the pollen grain reaches the stigma of a compatible species.
- It gives weight to the pollen grain, allowing it to cling better to the body surfaces of insect pollinators.
- The number of germ pores in dicots and monocots respectively are:
- One and three.
- Three and two.
- Two and three.
- Three and one.
Read the following and answer any four questions from S(i) to S(v) given below: Rajat is a student of biotechnology. His professor tells him that for transformation with recombinant DNA the bacterial cells must be made capable of taking up DNA as DNA do not pass through membrane. While doing experiment in the lab, Rajat noticed that bacterial cells were not taking up the foreign DNA even after treating it with sodium ion. He asked his professor, the reason behind this. His professor explained that he should check the valency and charge of the ion that he is using for the treatment.
- It is difficult for DNA to pass through the membrane as
- It is a hydrophilic molecule.
- It is a hydrophobic molecule.
- It is a circular molecule.
- It changes its shape when it comes in contact with host cell.
- What type of ions are used for DNA mediated gene transfers?
- Divalent anions.
- Divalent cations.
- Monovalent cations.
- Monovalent anions.
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- reduced DNA
- red DNA
- recombinant DNA
- related DNA.
- Which of the following statements with regard to DNA is correct?
- DNA is a positively charged molecule having two polynucleotide chains.
- Nitrogen bases of two polynucleotide chain form complementary pairs, i.e., A opposite G and T opposite C.
- Backbone of DNA chain is built up of alternate deoxyribose sugar and phosphate group.
- Both (a) and (c)
- Assertion: Competent host is essential for transformation with rDNA.
Reason: Transfer of DNA in a prokaryotic cell is called transfection.
- Both assertion and reason are true and reason is the correct explanation of assertion.
- Both assertion and reason are true but reason is not the correct explanation of assertion.
- Assertion is true but reason is false.
- Both assertion and reason are false.
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Green manuring is the fanning practice where a leguminous plant which has derived enough benefits from its association with appropriate species of Rhizobium, is ploughed into the field soil and then a non-legume is sown and allowed to get benefitted from the already present nitrogen fixer. Some legumes, such as, Crotolaria juncea, Sesbania rostrata, Lencaena leucocephala, etc. are used as green manure. Rhizobia, that fix atmospheric nitrogen in the form of nitrate, live in the roots ofleguminous plants. These nutrients are used by non-leguminous plants through the practice of green manuring.
Green manuring is the fanning practice where a leguminous plant which has derived enough benefits from its association with appropriate species of Rhizobium, is ploughed into the field soil and then a non-legume is sown and allowed to get benefitted from the already present nitrogen fixer. Some legumes, such as, Crotolaria juncea, Sesbania rostrata, Lencaena leucocephala, etc. are used as green manure. Rhizobia, that fix atmospheric nitrogen in the form of nitrate, live in the roots ofleguminous plants. These nutrients are used by non-leguminous plants through the practice of green manuring.
- Green manures mainly provide nutrient enriched in:
- Magnesium.
- Sulphur.
- Nitrogen.
- Both (a) and (b).
- Which of the following plants is used as green manure in crop fields?
- Saccharum.
- Dichanthium.
- Phyllonthus.
- Crotolaria.
- Green manure plants belong to the Family:
- Lamiaceae.
- Papilionaceae.
- Liliaceae.
- Poaceae.
- Due to excess use of chemical fertilisers rich in nitrate, ________ disease occurred in children.
- Jaundice.
- Septicemia.
- Methemoglobinemia.
- Botulism.
- A green manure is:
- Rice.
- Maize.
- Sorghum.
- Sesbania.
Write a short note on pollination by wind.
Read the following and answer any four questions from (i) to (v) given below: A technique known as amniocentesis is used to determine fetal abnormalities. This test chromosomal pattern in amniotic fluid. However, this technique is legally banned now. 
- Identify X and Y in the above given figure.
| S. No | X | Y |
| (a) | Amnion | Chorion |
| (b) | Uterine wall | Placenta |
| (c) | Placenta | Uterine wall |
| (d) | Uterine wall | Amnion |
- What is the function of Z?
- Z is an amniotic fluid which prevents dessication of an embryo.
- Z is yolk sac which functions as site of early blood cell formation.
- Z is amnion, which takes part in placenta formation.
- None of these
- Which of the following diseases can not be diagnosed by amniocentesis?
- Down's syndrome.
- Sickle cell disease.
- Jaundice.
- Cystic fibrosis.
- Assertion: Amniocentesis is legally banned for sex determination.
Reason: Amniocentesis was being misused for aborting normal female fetus.
- Both assertion and reason are true, and reason is the correct explanation of assertion.
- Both assertion and reason are true, but reason is not the correct explanation of assertion.
- Assertion is true, but reason is false.
- Both assertion and reason are false.
- Which of these is a non-invasive technique of detecting fetal disorder?
- Fetoscopy.
- Chorionic villi sampling.
- Amniocentesis.
- Ultrasound imaging.
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