Question

Dehydrated thick-walled bacterial cells having dipicolinic acid are
A) Endospores
B) Conidia
C) Exospores
D) Oidia

Answer 1

Hint:Spores are defined as the unicellular, solitary, and reproductive structures. Spores occur in various shapes, sizes, and spores’ size are variables, and numbers. These are reproductive structures that are highly resistant to adverse environmental situations such as temperatures (low or high pH, salt concentration, dehydration, toxic chemicals conditions, etc.

Complete answer:
Spores are usually categories into two categories on the basis of situation or position which are:
i) Endospore or internal spoore
ii) Exospore or external spore

The process of production of spores by the vegetative cells is termed as Sporulation. Sporulation is also sometimes named as sporogenesis. Sporulation gives a multi-layered structure as in the case of bacteria that is useful as it can be maintained for a long time.

Now let us find solution from given options:
A) Endospores : Endospores are made up of DNA and a small amount of cytoplasm which is surrounded by a protective outer shell. The endospore cell wall is composed of dipicolinic acid which endospore properties of resistance.
B) Conidia : These are exospores produced by fungi.
C) Exospores : Exospore are bacterial resistant spores that are produced either by fungi or algae but they do not have dipicolinic acid.
D) Oidia : These are exospores produced by algae.

Thus the correct answer is option ‘A’ i.e, Endospore.

Note:Bacterial endospores when provided with the heat be destroyed by the humid or moist heat treatment done at 121°C for 15 minutes. Endospores give rise to new organisms when the environmental conditions become favourable. This is the reason that internal spores can be considered as a type of reproductive or germ cells. Endospores show resistance to temperatures and can withstand adverse conditions like toxic chemicals, are quite resistant to dehydration, and UV radiation.