NEET BIOLOGY

Detailed explanation-1: -Streptococci are nonmotile, Gram-positive, nonsporeforming bacteria, that live in pairs or chains of varying length. They are characteristically round or ovoid in shape. Most Streptococci are facultative anaerobes, although some are obligate anaerobes.

Detailed explanation-2: -Streptococci are facultative anaerobic organisms or obligate anaerobes that are spherical or ovoid and found in pairs or chains.

Detailed explanation-3: -Streptococcus pneumoniae are lancet-shaped, gram-positive, facultative anaerobic bacteria with more than 100 known serotypes.

Detailed explanation-4: -Spherical bacteria are known as cocci, rod-shaped bacteria are bacilli, and spiral-shaped bacteria are spirilla.

Detailed explanation-5: -2.2 Streptococcus pyogenes. S. pyogenes belongs to Lancefield group A and is gram-positive (Figure 5.3(A)). Cells of this species have a diameter of 0.5–1.0 m and are usually spherical.