Question

(a) Answers the Following
(i) State the role of nitrifying bacteria.
(ii) State three harmful effects of bacteria.
(b)The given figure shows a type of muscle.

(i) Identify the muscle.
(ii) Label parts 1 and 2.
(iii) Where is it located?
(iv) What are the characteristics of this tissue?

Answer 1

(a) (i) Nitrifying bacteria convert ammonia into nitrites during nitrogen fixation and this process is called nitrification.
(ii) Harmful effects of bacteria:
1. Bacteria carry out the process of decay or fermentation, resulting in the spoilage of food materials.
2. Bacteria cause many diseases in animals and plants. For example, Vibrio cholera causes cholera in humans. Xanthomonas malvacearum causes angular leaf spot in the cotton plant.
3. Some bacteria are also used by some countries in biological warfare to make bombs which when exploded release disease-causing germs. For example – Anthrax bacteria.

(b) (i) Striated muscles
(ii) 1- Dark bands/A-bands 2-Light bands/I-bands
(iii) Striated muscles are attached to the bones of limbs.
(iv) Characteristics of striated muscles: 1. Muscles fibres are multi-nucleated.
2. Muscle fibres are long, cylindrical and unbranched.
3. The cells are enclosed in connective tissue sheaths in the form of bundles. These sheaths form tendons that connect muscles with the bones.
4. These muscles are voluntary