CBSE Class 10 Answered

(a)

(b) The digestion of carbohydrates (starch) starts in the mouth. The saliva has salivary amylase or ptyalin enzyme which acts on the starch and converts it into maltose sugar. The partially digested food reaches the stomach where the food gets mixed with gastric juice secreted by gastric glands. The gastric juice contains large quantities of mucus, HCl and pepsin. The enzyme pepsin acts on proteins and coverts them into peptones and proteoses. The gastric lipase emulsifies fats.

Bile juice secreted from liver lipids into small droplets.

Pancreas secretes pancreatic juice which contains the pancreatic amylase, trypsin and lipase. Pancreatic amylase digests the leftover starches into maltose. Trypsin converts peptones and proteoses into small peptides. Lipase acts on small droplets and converts them into triglycerides.

The food reaches the small intestine where complete digestion of food takes place in the presence of an enzyme called succus entericus. The maltose converts into glucose, peptide emulsifies into amino acids and the triglycerides emulsifies into fatty acids and glycerol.[

OR

(a) In four chambered heart, left half is completely separated from right half by septa.This prevents oxygenated and deoxygenated blood from mixing. This allows a highly efficient supply of oxygenated blood to all parts of the body. This is useful in animals that have energy needs, such as birds and mammals.

(b)