Gram positive bacteria have a thick layer of peptidoglycan as their cell wall which provides strength and support to the bacteria. Complement-mediated lysis and attack system is based on the formation of complement proteins which form membrane attack complex that insert into the plasma membrane of the cell and undergo cell lysis. But, due to the thick protection of gram positive bacteria by peptidoglycan on the outer cell membrane, complement proteins cannot enter the cell and cause lysis.

Correct Option: A

Gram positive bacteria have a thick layer of peptidoglycan as their cell wall which provides strength and support to the bacteria. Complement-mediated lysis and attack system is based on the formation of complement proteins which form membrane attack complex that insert into the plasma membrane of the cell and undergo cell lysis. But, due to the thick protection of gram positive bacteria by peptidoglycan on the outer cell membrane, complement proteins cannot enter the cell and cause lysis.

Treponema pallidum is a spirochaete bacterium with subspecies that cause treponemal diseases such as syphilis, bejel, pinta, and yaws. It is a Gram-negative bacteria which is spiral in shape. It is generally susceptible to penicillin. ​

Correct Option: B

Treponema pallidum is a spirochaete bacterium with subspecies that cause treponemal diseases such as syphilis, bejel, pinta, and yaws. It is a Gram-negative bacteria which is spiral in shape. It is generally susceptible to penicillin. ​

There are 4 types of flagellar distribution on bacteria-

1. Monotrichous - Single polar flagellum- Example : Vibrio cholerae ​​
2.​ Amphitrichous - Single flagellum on both sides- Example : Alkaligens faecalis
​​3. ​Lophotrichous - Tufts of flagella at one or both sides- Example : Spirillum ​​
4.​ Peritrichous - Numerous falgella all over the bacterial body- Example : Salmonella Typhi ​.

Correct Option: C

There are 4 types of flagellar distribution on bacteria-

1. Monotrichous - Single polar flagellum- Example : Vibrio cholerae ​​
2.​ Amphitrichous - Single flagellum on both sides- Example : Alkaligens faecalis
​​3. ​Lophotrichous - Tufts of flagella at one or both sides- Example : Spirillum ​​
4.​ Peritrichous - Numerous falgella all over the bacterial body- Example : Salmonella Typhi ​.

The virus family Parvoviridae contains 3 genera : the parvoviruses , the dependoviruses, and the densoviruses (which only infect insects). Parvoviridae is the only family of DNA viruses that infect humans that is single stranded. The DNA strand packaged in the virion can be either negative or positive sense, though in case of some strains, it is always negative.

Correct Option: D

The virus family Parvoviridae contains 3 genera : the parvoviruses , the dependoviruses, and the densoviruses (which only infect insects). Parvoviridae is the only family of DNA viruses that infect humans that is single stranded. The DNA strand packaged in the virion can be either negative or positive sense, though in case of some strains, it is always negative.

Clostridium is a genus of Gram-positive bacteria, belonging to the Firmicutes. They are obligate anaerobes capable of producing endospores. Spirillum is genus of spiral-shaped bacteria of the family Spirillaceae. Spirillum is microbiologically characterized as a gram-negative, motile helical cell with tufts of whiplike flagella at each end. Treponemes are helically coiled, corkscrew-shaped cells, 6 to 15 µm long and 0.1 to 0.2 µm wide. They have an outer membrane which surrounds the periplasmic flagella, a peptidoglycan-cytoplasmic membrane complex, and a protoplasmic cylinder. Multiplication is by binary transverse fission. Methanobacteria are methane producing microorganisms (methanogens) and have pseudomurine in their cell wall. ​

Correct Option: A

Clostridium is a genus of Gram-positive bacteria, belonging to the Firmicutes. They are obligate anaerobes capable of producing endospores. Spirillum is genus of spiral-shaped bacteria of the family Spirillaceae. Spirillum is microbiologically characterized as a gram-negative, motile helical cell with tufts of whiplike flagella at each end. Treponemes are helically coiled, corkscrew-shaped cells, 6 to 15 µm long and 0.1 to 0.2 µm wide. They have an outer membrane which surrounds the periplasmic flagella, a peptidoglycan-cytoplasmic membrane complex, and a protoplasmic cylinder. Multiplication is by binary transverse fission. Methanobacteria are methane producing microorganisms (methanogens) and have pseudomurine in their cell wall. ​