Economic Importance of Fungi Long Answer Biology Class-9 ICSE Selina Publishers Solutions Chapter-9 Part B. Step By Step ICSE Selina Concise Solutions of Chapter-9 Economic Importance of Fungi with Exercise-9B including MCQs, Very Short Answer Type, Short Answer Type, Long Answer Type and Structured/Application Questions Solved . Visit official Website CISCE for detail information about ICSE Board Class-9.
Economic Importance of Fungi Exe-9B Long Answer Biology Class-9 ICSE Concise Selina Publishers
| Board | ICSE |
| Publications | Selina Publication |
| Subject | Biology |
| Class | 9th |
| Chapter-9 | Economic Importance of Bacteria and Fungi |
| Book Name | Concise |
| Topics | Solution of D. Long Answer Type Part B |
| Academic Session | 2023-2024 |
D. Long Answer Type
Economic Importance of Fungi Class-9 Biology Concise Solutions
Page 100
Question 1.
Discuss the role of yeasts in bakeries and breweries.
Answer:
During the baking process, yeast added to the dough ferments sugar and produces carbon dioxide. This causes the dough to rise and when it is baked, the gas bubbles expand causing the bread to be spongy and light. Hence yeast is used in bakeries.
The greatest importance of yeast to us is through their property of alcoholic fermentation. Fermentation is the process in which the micro-organisms like yeast break down the carbohydrates into simpler products like ethanol and lactic acid. This alcohol is of great commercial importance. Hence, yeast is used in breweries to produce beer and wine from barley maltose and grapes, respectively.
Question 2.
Write in proper sequence the five major steps in the cultivation of the common edible mushroom.
Answer:
Five major steps in the cultivation of common edible mushrooms are:
- Composting — Composting involves mixing of various components such as
- Paddy straw or Wheat
- Organic and Inorganic fertilizer
- Chicken manure
The temperature of the compost is kept for about one week under 50°C.
- Spawing — ‘Mushroom seed’ in the form of mycelium of mushroom to be grown is introduced into the heap of compost and left for spreading for around two days.
- Casing — It is an important step wherein a thin layer of soil is spread over the compost. It:
- Gives support to the mushroom
- Prevents quick drying of the compost
- Provides humidity
- Assists to check temperature
- Cropping & Harvesting — The growth occurs in three principal stages:
- Mycelium grows within 2-6 weeks
- Tiny pin heads
- Button stage grows bigger attaining marketable size
- Fully grown mushrooms are taken out.
- Preservation — Shelf life of mushroom can be increased by the following processes:
- Vacuum cooling
- Storing at 15 degree Celsius and giving gamma radiation
- Freeze drying in a solution of ascorbic acid, citric acid, and brine etc.
Question 3.
Would you consider bacteria and yeast as plants? Give reason.
Answer:
We cannot consider bacteria and yeast as plants. The reasons for it are as given below:
(i) They lack chlorophyll (except a few bacteria). Their mode of nutrition is heterotrophic instead of autotrophic.
(ii) Bacteria are prokaryotic and lack membrane bound organelles.
(iii) Fungi is multicellular but it is not differentiated into root, stem and leaves.
Question 4.
Both bacteria and yeast reproduce by asexual method, but how does this method differ in them ?
Answer:
Bacteria reproduces by cell division or binary fission. The circular DNA duplicates. The cell expands and the two DNA are pulled apart. The cell constricts at the middle separating the two cells.
Fungi like yeast reproduce by budding. In budding, a small bud or daughter cell is formed on the parent cell. The bud continues to grow until it separates from the parent cell, forming a new cell.
— : End of Economic Importance of Fungi Part (B) D. Long Answer Class-9 ICSE Biology Solutions :–
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