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Why does endosperm development precede embryo development in angiosperm seeds?
Concept: Endosperm
One of the major approaches of crop improvement programme is Artificial Hybridisation. Explain the steps involved in making sure that only the desired pollen grain pollinate the stigma of a bisexual flower by a plant breeder.
Concept: Artificial Hybridization or Artificial Fertilization
Women are often blamed for producing female children. Consequently, they are ill-treated and ostracized. How will you address this issue scientifically if you were to conduct an awareness programme to highlight the values involved?
Concept: Gametogenesis
Comment on the role of placenta as an endocrine gland.
Concept: Pregnancy and Embryonic Development
Your school has been selected by the Department of Education to organize and host an interschool seminar on “Reproductive Health – Problems and Practices”. However, many parents are reluctant to permit their wards to attend it. Their argument is that the topic is “too embarrassing.” Put forth four arguments with appropriate reasons and explanation to justify the topic to be very essential and timely.
Concept: Concept of Reproductive Health
Name the group of genes that have been identified in normal cells that could lead to cancer. How do these genes cause cancer?
Concept: Sexually Transmitted Diseases (STD) or Sexually Transmitted Infections (STI)
Reproductive and Child Healthcare (RCH) programmes are currently in operation. One of the major tasks of these programmes is to create awareness amongst people about the wide range of reproduction related aspects. As this is important and essential for building a reproductively healthy society.
- “Providing sex education in schools in one of the ways to meet this goal.” Give four points in support of your opinion regarding this statement.
- List any two ‘indicators’ that indicate a reproductively healthy society.
Concept: Concept of Reproductive Health
Indiscrimate diagnostic practices using X-rays etc., should be avoided. Give one reason.
Concept: Sexually Transmitted Diseases (STD) or Sexually Transmitted Infections (STI)
Our government has intentionally imposed strict conditions for M.T.P. in our country. Justify giving a reason.
Concept: Concept of Reproductive Health
Write the complete name of the diagnostic test for AIDS.
Concept: Sexually Transmitted Diseases (STD) or Sexually Transmitted Infections (STI)
Given below are Column A with a list of certain Assisted Reproductive Technologies (ART) and in Column B the procedures followed during ART:
| Column A | Column B | ||
| S. No. | Names of ART | S. No. | Procedures |
| (A) | GIFT | (i) | Transfer of ovum from a donor into the fallopian tube of another female. |
| (B) | ICSI | (ii) | Transfer of semen from the donor into the vagina of the female. |
| (C) | ZIFT | (iii) | Injecting sperm directly into the ovum. |
| (D) | IUI | (iv) | Transfer of early embryos into the fallopian tube. |
Choose the option where ART correctly matches with the procedure.
Concept: Infertility
Assertion (A): Determining the sex of an unborn child followed by MTP is an illegal practice.
Reason (R): Amniocentesis is a practice to test the presence of genetic disorders also.
Concept: Induced Abortion or Medical Termination of Pregnancy (MTP)
How many chromosomes do drones of honey bees possess?
Concept: Chromosomal Theory of Inheritance
Write the types of sex-determination mechanisms the following crosses show. Give an example of each type.
(i) Female XX with Male XO
(ii) Female ZW with Male ZZ
Concept: Sex Determination
Public all over India is very much concerned about the deteriorating air quality in large parts of North India. Alarmed by this situation the Resident’s Welfare Association of your locality organized an awareness programme entitled “Bury not burn”. They invited you, being a biology student to participate.
- How would you justify your arguments that promote burying and discourage burning? (Give two reasons.)
- With the help of flow charts, one for each practice depicts the chain of events that follow.
Concept: Effects of Domestic Sewage and Industrial Effluents on Water
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The chromosome number is fixed for all normal organisms leading to species specification whereas any abnormality in the chromosome number of an organism results into abnormal individuals. For example, in humans, 46 is the fixed number of chromosomes both male and female. In males it is '44 + XY' and in females, it is '44 +XX'. Thus the human male is heterogametic, in other words produces two different types of gametes one with '22 + X' chromosomes and the other with '22 + Y' chromosomes respectively. Human female, on the other hand, is homo gametic i.e. produce only one type of gamete with '22 + X' chromosomes only. Sometimes an error may occur during the meiosis of the cell cycle, where the sister chromatids fail to segregate called nondisjunction, leading to the production of abnormal gametes with altered chromosome numbers. On fertilisation, such gametes develop into abnormal individuals. |
(a) State what is aneuploidy. (1)
(b) If during spermatogenesis, the chromatids of sex chromosomes fail to segregate during meiosis, write only the different types of gametes with altered chromosome numbers that could possibly be produced. (1)
(c) A normal human sperm (22 + Y) fertilises an ovum with karyotype '22 +XX'. Name the disorder the offspring thus produced would suffer from and write any two symptoms of the disorder. (2)
OR
(c) Name the best-known and most common autosomal aneuploid abnormality in humans and write any two symptoms. (2)
Concept: Human Genetic Disorders >> Chromosomal Disorders or Abnormalities
What is a cistron?
Concept: Transcription Unit and the Gene
- Name the scientist who suggested that the genetic code should be made of a combination of three nucleotides.
- Explain the basis on which he arrived at this conclusion.
Concept: Transcription
Name the transcriptionally active region of chromatin in a nucleus.
Concept: Packaging of DNA Helix
Differentiate between a DNA and a RNA nucleotide.
Concept: Properties of Genetic Material
