NIOS CLASS 12TH Biology (314) SOLVED TMA In English Medium PDF SESSION 2024 - 25

Ques 1. (a) Arrange the stages of Meiosis I in the correct order: leptotene, zygotene, Pachytene, Diakinesis, Metaphase-I, Anaphase-I, Telophase-I. How does the correct sequence of these stages contribute to the process of cell division, and what is the significance of each stage ?
Ans - The correct sequence of stages in Meiosis I is as follows:
1. Leptotene
2. Zygotene
3. Pachytene
4. Diakinesis
5. Metaphase-I
6. Anaphase-I
7. Telophase-l
Each stage plays a crucial role in ensuring the proper reduction of chromosome number and the generation of genetic diversity during the formation of gametes (sperms and eggs).
Manish
1. Leptotene (Prophase 1):
Significance: This is the beginning of chromosome condensation, crucial for the subsequent pairing of homologous chromosomes. It sets the stage for homologous recombination and genetic variation.
2. Zygotene (Prophase 1):
Significance: This pairing ensures that each gamete receives one set of chromosomes from each parent. It allows for genetic recombination, which increases genetic diversity.
3. Pachytene (Prophase I):
Significance: The exchange of genetic material between homologous chromosomes generates genetic diversity, ensuring that the offspring have a mix of traits from both parents.

4. Diakinesis (Prophase 1):
Significance: The homologous chromosomes are prepared for segregation, and the spindle fibers are ready to attach to the kinetochores, ensuring the proper distribution of chromosomes.
5. Metaphase-l:
Significance: Random alignment of homologous chromosomes contributes to independent assortment, another mechanism contributing to genetic diversity in gametes.
6. Anaphase-l:
Significance: This stage reduces the chromosome number by half, as each daughter cell will receive only one chromosome from each homologous pair (haploid set), ensuring the production of haploid gametes.
7. Telophase-l:
Significance: The first division is complete, and the cells now contain a haploid set of chromosomes, setting the stage for Meiosis II, where sister chromatids will be separated.

Ques 2. (a) State any two activities which will help in sustainable development. Name any two endangered animals of India.
Ans - Two activities that promote sustainable development are:
1. Afforestation: Planting trees to restore ecosystems and enhance biodiversity.
2. Water conservation: Implementing efficient irrigation and rainwater harvesting to sustainably manage water resources.
Two endangered animals of India are the Bengal tiger and the Asian elephant, both of which face threats due to habitat loss and poaching.

Ques 3. (a) What are two ways in which Mitochondria and Chloroplasts are similar ?
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Ques 4. (a)
I. Name and briefly state three chemicals in the human body whose concentrations
need to be regulated at specific levels 

II. Define the terms below and provide one or more synonymous terms for each :
(i) Poikilotherms (ii) Homoiotherms. 

5. (a) How can we improve the use of cellophane in hemodialysis to help patients, and why do we need to decide whether to use an artery or a vein to take out blood during the treatment, and how does it affect the patient ? 

6. Collect from internet/newspapers/magazines/media/help from others or any other source, the weather data for the March-April this year and the previous year. Make a comparative analysis of your collected data and record the changes in temperature and climate. Global warming is considered to be responsible for climate change. Record your observations and conclusions and explain causes and consequences of global warming. You may relate the collected data to the explanation. You may make a PowerPoint presentation or prepare a written account.
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