How does an animal cell react when there is no glucose available to carry out cellular respiration?

a) it carries out ethyl alcohol fermentation.

b) it breaks down polysaccharides such as starch.

c) it produces other sugars through photosynthesis.

d) it carries out lactic acid fermentation.

B) It breaks down polysaccharides such as starch.

Explanation:

Polysaccharides are long chains of monosaccharides like glucose joined together with glycosidic linkages. While plants can simply make glucose via photosynthesis, animals rely on glucose sourced from their diet. In animals, glucose is stored as glycogen; however, plant storage polysaccharides like starch are regularly broken down through digestion using enzymes.

Enzymes are proteins which catalyze chemical reactions like the breakdown of large polysaccharides. Alpha amylase, an enzyme produced in the pancreas, is also found in human saliva; it catalyzes the hydrolysis, or breakdown of starch into glucose. Amylase acts on polysaccharides bonds at random points along the chain by splitting the α 1-4 glycosidic bonds. This produces maltose, dextrin and glucose; this glucose is used in ATP synthesis via respiration, ethyl alcohol fermentation and lactic fermentation.

Option B ,

Explanation:

When there is no sufficient glucose available for cellular respiration, the cell in animals starts decomposing molecules also known as polysaccharide that could satisfy their glucose requirement. Some of the common polysaccharide in animals are - Amylose and amylopectin (plant starch found in animals), glycogen, cellulose, lipids and proteins etc. These poly saccharides are  complex compounds containing glucose matrix which are broken down with the assistance of an enzyme to release glucose.

Hence, option B is correct