Question

Rod-shaped bacteria are called
a. Coccus
b. Spirillum
c. Bacillus
d. Actinomyces

Answer 1

Hint: Bacteria are the biological cells, and they contain a large domain of prokaryotes, and range a few micrometers in length, bacteria are considered as first life forms to appear on the earth, and they present in almost all habitats.

Complete answer:
- Bacteria shapes are ranging from spheres, rods, and spirals.
- Bacteria are present both as symbiotic and parasitic forms.
- Most of the animals contain bacteria of the archaea where this contains all the enzymes to synthesize the vitamin B12 or cobalamin which is required for various metabolism’s in the body.
- Bacteria is the single-cell organism, and they lack so many organisms, such as chloroplast and the mitochondria, and bacteria do not contain the true nucleus, they contain double-strand DNA which is circular in shape, and it is called as nucleolus and they lack nucleoid membrane.
- Bacteria contain the cell membrane and cell wall, and they have Peptidoglycans in the cell wall.
- They mainly reproduce through binary fission.

Types of bacteria based on their shape.
> Cocci: These are spherical or ovoid-shaped bacteria, when these bacteria undergo binary fission, sometimes they do not detach and stick but they form
Diplococcus - a pair of cocci,
Streptococcus - a chain of cocci,
Staphylococcus - a cluster of cocci,
Tetrads are 4 cocci forming square shape,
Sarcinae: cube-shaped form by 8 cocci.

> Bacillus: These are rod-shaped bacteria, similar to cocci, these are arranged either solitary or normal.
Diplobacillus - 2 bacilli together,
Streptobacilli - a chain or bacillus.

> Spiral shaped bacteria, they are
Spirillum: thick and tough spiral.
Spirochetes: thin and flexible spiral.
Vibrios: comma-shaped rods with a twist.

Hence, the correct answer is option (C).

Note: Based on gram staining, there are 2 types of bacteria, they are gram +ve and gram -ve. This gram staining is based on the peptidoglycan in the cell wall, and cells that retain primary color are gram positive while which loses the color are gram-negative.