What would happen if gametes are formed by mitotic divisions? Class 9
What would happen if gametes are formed by mitotic divisions? Class 9
Question 1.
What would happen if gametes are formed by mitotic divisions? Class 9
Answer:
If gametes are formed by mitosis, they will have the same number of chromosomes as body cells. After fertilisation, the chromosome number will double, leading to imbalance and abnormal development.
- Mitosis produces cells with the same number of chromosomes as the parent cell.
- Normally, gametes are formed by meiosis, which reduces the chromosome number to half.
Question 2.
A farmer, Deepa, was very happy with the harvest of amla (Indian Gooseberry) and lemons on her farm. However, she could sell only one-fourth of the produce in the local market. Recognising that a significant amount of produce may be lost post-harvest, she employed a traditional yet scientifically sound method to extend the shelf life of amla and lemons. She turned perishable produce into profitable products, such as pickles and sharbat. She used the excess produce to prepare pickles, murabbas, and sharbat by adding appropriate amounts of salt, sugar, or jaggery to small pieces of fruit and their juices. These were then stored in small glass bottles for sale, helping her prevent the wastage of post-harvest produce. This shift from farming to agro-processing would strengthen food security and boost the local economy, creating a sustainable model that cuts waste while increasing her income. Based on the above passage answer the following questions: Class 9
(i) Which scientific concept has the farmer applied in the preservation of the farm produce?
Answer:
Farmer Deepa has applied the concept of osmosis. By adding high concentrations of salt, sugar, or jaggery to the fruit, she creates a hypertonic environment around the microorganisms (bacteria and fungi) that cause spoilage. Water moves out of the microbial cells by osmosis, causing them to shrink and die - this prevents the food from spoiling.
(ii) How does the addition of high concentrations of salt and sugar create an environment that prevents the growth of spoilage-causing bacteria and fungi?
Answer:
When bacteria or fungi are placed in a high- concentration salt or sugar solution, the external solute concentration is much greater than inside their cells (hypertonic condition). Water moves out of the microbial cells through osmosis, causing them to shrink and die. Without water, microorganisms cannot grow or reproduce, preventing spoilage.
(iii) Suggest a healthy recipe of this kind for food preservation.
Answer:
Amla (Indian Gooseberry) Murabba:
- Wash and prick amla fruits with a fork Boil briefly to soften slightly
- Prepare a sugar syrup (equal weight of sugar and amla)
- Add the amla to the syrup along with a small amount of cardamom and saffron
- Cook until the syrup thickens Store in a clean, sterilised glass jar
This preserves amla for months while retaining its Vitamin C content. The high sugar concentration prevents microbial growth through osmosis.
(iv) What are the scientific values addressed in this case?
Answer:
Application of scientific knowledge to solve a practical problem (osmosis used for food preservation)
- Sustainability - reducing post-harvest waste and extending shelf life of produce
- Innovation - converting perishable produce into value-added products (pickles, sharbat, murabba)
- Economic value - increasing farmers’ income and boosting local economy
- Food security - making nutritious food available for longer periods
- Traditional knowledge - scientific validation of traditional preservation methods passed down through generations