1. What is the chemical nature of the circular single chromosome of a bacterium? 

Ans. DNA.

2. Name the special region in the bacterial cell where genetic material lies.

Ans. Nucleoid.

3. What is the main component of cell wall in prokaryotes?

Ans. Peptidoglycan.

4. State one point of difference between flagella and pili.

Ans. Difference between Flagella and Pili:

5. Give one difference between aerobic and anaerobic bacteria.

Ans. Difference between Aerobic an Anaerobic Bacteria:

6. What is transferred during sexual recombination in a bacterium?

Ans. A fragment of DNA strand in transferred.

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1. Name of the bacteria that:

(i) Fix the atmospheric nitrogen in the soil ___________.

Ans. Rhizobium leguminosarum.

(ii) Set milk into curd ___________.

Ans. Lactobacillus.

(iii) Cause tuberculosis ____________.

Ans. Mycobacterium tuberculosis.

(iv) Cause tetanus ___________.

Ans. Clostridium tetani.

2. Approximately how many bacteria may be obtained from one bacterium in an hour?

Ans. The number is approximately eight. 

3. Give any three differences between bacteria and cyanobacteria.

Ans. Differences between Bacteria and Cyanobacteria:

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Q.1. Protoctists are single called like the Monera. Why have they been put in a sepa-rate kingdom? Answer in one short sentence.

Ans. The protists are eukaryotes having a true nucleus.

Q.2. Name the protozoan which causes:

(i) Amoebic dysentery.

Ans. Entamoeba histolytica.

(ii) Malaria.

Ans. Plasmodium vivax or malarial parasite.

Q.3. Which is the kind of asexual reproduction found in Protoctista?

Ans. Asexual type-binary fission occurs.

Q.4. Through which organelle of the protoctists does respiration occur?

Ans. By mitochondria respiration occurs.

Q. 5. Name the organelle responsible for regulating water content (osmoregulation) in amoeba.

Ans: Contractile vacuole (C.V.) in amoeba.

6. Name two kinds of locomotion found in protoctista.

Ans: (i) Pseudopodial (by pseudopodia). 

(ii) Ciliary (by means of cilia).

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Q.1. Name the slender filaments that form the body of a fungus.

Ans: Mycelium (made of Hyphae).

Q.2. What are types of reproduction found in fungi?

Ans: (a) Asexual. and 

(ii) sexual reproduction. 

Q.3. Draw two small figures to show asexual reproduction in yeast.

Ans: See Fig. 2.25:

Fig. 2.25. Budding in Yeast (a) A bud is forming and nucleus is dividing.

(b) Bud formed and nucleus divided.

(c) Further Budding forms a chain.

Q.4. Which are the four main kinds of fungi?

Ans’ (a) Slime moulds.

(b) Mushrooms and toadstools.

(c) Yeasts. and 

(d) Lichens.

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Q.1. Name:

(i) The fungus from which Penicillin is  extracted _________.

Ans: Penicillium notatum.

(ii) A is unicellular fungus ____________.

Ans: Yeast.

(iii) The fungus which causes wheat rust __________.

Ans: Puccinia graminis tritici.

(iv) The whitish cottony mass growing on stale bread is __________.

Ans: Mycelium, Rhizopus.

(v) Two common diseases caused by fungi _________.

Ans: Ringworm and athlete’s foot.

 2. Who discovered antibiotic properties of penicillin?

Ans. Alexander Flemming (1928).

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1. Draw a labelled diagram of a typical bacterial cell.

Ans: See Fig. 2.26, below:

2. List the different nutritional categories of bacteria and protoctists. 

Ans: Four nutritional categories of Bacteria and Protoctists:

Q. 3. Draw the labelled diagrams to show binary fission in bacteria.

Ans: See Fig.

Fig. 2.27. Binary Fission in Bacteria.

4. How does amoeba normally reproduce? Draw diagrams to represent the process. 

Ans: Reproduction in Amoeba: It repro-duces by binary fission normally. A cell divides into two daughter cells.

Fig. 2.28. Asexual Reproduction in Amoeba

5. Draw a labelled diagram of Euglena.

Ans: See the figure.

Fig. 2.29. Euglena.

6. What are the common features of diatoms which justify their inclusion in protoctists?

Ans: (i) Diatoms are eukaryotic and unicellular organisms.

(ii) These occur in fresh water, marine water and soil.

(iii) Diatoms have nucleus and chloroplasts. 

(iv) They have membrane bound cell organelles.

7. Write a paragraph on economic importance of the protoctists?

Ans. Economic importance of the protoctists:

(i) Some protozoan protists cause diseases in man, e.g., Plasmodium causes malaria. Entamoeba histolytica causes amoebic dysentery in man.

(ii) Diatoms form phytoplankton of the oceans which are producers.

(iii) Diatoms are used as food by aquatic animals.

(iv) Diatoms form diatomaceous earth. 

8. List any three characteristics of fungi.

Ans: Three characteristics of fungi: 

(i) Plant body made up of hyphae which may be septate or aseptate.

(ii) All fungi are eukaryotic.

(iii) All fungi are heterotrophs.

9. What are mycorrhizae?

Ans: Mycorrhizae: It is symbiotic association of fungus with the roots of higher plants. There are two types of mycorrhizae-endomycorrhizae growing within the root surface and ectomycorrhizae growing around the root surface. The epiphytic orchid roots are related with mycorrhizae. The fungus helps in the absorption of water, nitrogen and other minerals from the soil.

Fig. 2.30. Showing Pinus roots bearing (A) Mycorrhizae, (B) Coralloid type of mycorrhizal root, (C) Tuberous mycorrhizae bearing root.

10. Name three harmful fungi mentioning their harmful effects.

Ans: Three Harmful Fungi:

(a) Rhizopus: It spoils the breads.

Fig. 2.31. Rhizopus spoiling bread. 

(b) Penicillium: It spoils the leather goods.

Fig. 2.32. Penicillium spoiling leather goods. 

(c) Puccinia graminis tritici: It causes black rust of smut. It decrease crop yield.

Fig. 2.33. Life cycle of Puccinia graminis.

11. Write a note on beneficial fungi.

Ans: Beneficial Fungi:

(i) Some fungi are used as food, e.g., Agaricus campestres.

(ii) Yeast (Saccharomyces cerevisiae) is used in making bread.

(iii) Aspergillus niger is used in making alcohol.

(iv) Penicillium camembertii is used in making cheese.

(v) Fungi also Produce amylase and zymase enzymes.

(vi) Fungi used in the formation of antibio-tics. Penicillin is extracted from Peni-cillium notatum and P. chrysogenum.

(vii) Fungi are used in research e.g., Neurospora crassa.

12. Draw labelled diagrams of the following: 

(i) A series of stages in the budding of yeast. 

(ii) Magnified view of the bread mould growing on bread.

Or

Draw a diagram of magnified view of bread mould and label the following parts:

(a) Sporangium 

(b) Rhizoids 

Ans: See the figures.

Fig. 2.34. Stages in budding of Yeast.

Fig. 2.35. Magnified view of bread mould growing on bread.