Endospore structures are resistant to heat and chemicals because of in their protective covering.

The spore coat (proteinous coat)

Explanation:

Endospore is usually a position taken by a gram positive bacteria when it lacks nutrient. Endo- means within and the-spore means offspring. This is a complex stage which is a dormant and highly resistive cell wall that allows the bacteria preserve its genetic materials in times of deprivation within this protective cell.

They are also resistant to UV radiation, heat and chemicals. Once the environment become favourable, they reactivate from this vegetative state and absorb nutrients. This vegetative state consists of the following layers:

1. The outer coating called the exosporium which surrounds the spore is the thin layer responsible for covering the spore coat.

2. The proteinous coating which is the spore coat is the next layer which as a sieve. It is resistant to chemical and other toxins.

3. After this proteinous coating is a thick peptidoglycan called the cortex.

3. A cell/core wall which resides under the cortex. This layer will become the cell wall of the bacterium after the endospore germinates.

5. The center/core of the endospore js the next. The core has the spore chromosomal DNA and some cell structures, such as ribosomes and enzymes but is inactive.