1. Complete the statements using the proper option from those given below. Explain the statements.
(mycotoxins, budding, rhizobium)
a. Yeast reproduces asexually by the budding method.
Explanation: In budding, a small outgrowth (bud) forms on the parent yeast cell, which grows and eventually detaches to become a new individual.
b. Toxins of fungal origin are called mycotoxins.
Explanation: Mycotoxins are toxic secondary metabolites produced by fungi, which can contaminate food and cause health issues in humans and animals.
c. Leguminous plants can produce more proteins due to rhizobium.
Explanation: Rhizobium is a nitrogen-fixing bacterium that forms symbiotic associations with roots of leguminous plants, converting atmospheric nitrogen into usable forms, thereby enhancing soil fertility and plant protein synthesis.
2. Write the names of microbes found in following food materials.
- Yoghurt: Lactobacillus bulgaricus, Streptococcus thermophilus
- Bread: Saccharomyces cerevisiae (yeast)
- Root nodules of leguminous plants: Rhizobium
- Idli: Leuconostoc mesenteroides, Saccharomyces cerevisiae
- Dosa: Leuconostoc, Lactobacillus, yeast
- Spoiled potato curry: Clostridium botulinum, Bacillus cereus, molds like Aspergillus
3. Identify the odd word out and say why it is the odd word.
a. Chicken pox – It is a viral disease; the others are bacterial diseases.
b. Yeast – It is a fungus; the others are bacteria.
c. Rubella – It is a viral disease in humans; the others are plant diseases.
4. Give scientific reasons.
a. Foam accumulates on the surface of ‘idli’ kept for a long time in summer because fermentation increases in warm temperatures. Yeast and bacteria produce carbon dioxide gas, which forms foam.
b. Naphthalene balls are kept with clothes to be put away because they sublimate and release fumes that repel or kill insects and moths, preventing damage to fabrics.
5. Write down the modes of infection and the preventive measures against fungal diseases.
Modes of infection:
- Direct contact with an infected person/animal
- Inhalation of fungal spores
- Contaminated soil, water, or surfaces
- Weakened immune system
- Preventive measures:
- Maintain personal hygiene
- Keep skin dry and clean
- Avoid sharing personal items
- Use antifungal powders/sprays
- Ensure proper sanitation and ventilation
- 6. Match the pairs.
- Rhizobium – b. Nitrogen fixation
- Clostridium – a. Food poisoning
- Penicillium – d. Production of antibiotics
- Yeast – c. Bakery products
- 7. Answer the following questions.
- a. Which vaccines are given to infants? Why?
- Vaccines such as BCG, OPV, DPT, MMR, and Hepatitis B are given to infants to build immunity against serious diseases early in life when they are most vulnerable.
- b. How is a vaccine produced?
- Vaccines are produced by using weakened or killed pathogens, their toxins, or subunits. These are processed to trigger an immune response without causing the disease.
- c. How do antibiotics cure disease?
- Antibiotics inhibit the growth of or kill bacteria by targeting their cell walls, protein synthesis, or DNA replication.
- d. Are the antibiotics given to humans and animals the same? Why?
- Not always. Some antibiotics are common, but dosage and type may vary due to differences in physiology and disease types. Misuse can lead to antibiotic resistance.
- e. Why is it necessary to safely store the pathogens of a disease against which vaccines are to be produced?
- To ensure a steady supply for vaccine production, research, and to maintain strain viability for future use.
- 8. Answer the following questions in brief.
- a. What are ‘broad-spectrum antibiotics’?
- Antibiotics that are effective against a wide range of both Gram-positive and Gram-negative bacteria.
- b. What is fermentation?
- A metabolic process where microorganisms like yeast and bacteria convert sugars into alcohol, acids, or gases in the absence of oxygen.
- c. Define ‘Antibiotic’.
- A chemical substance produced by microorganisms that inhibits the growth or kills other microorganisms.