EXP 10

• What is alimentary digestion?

  It is the process of rendering ingested food materials assimilable.
• What is the role of the lymphatic system in digestion?

  It consists of enzymatic reactions that convert colloidal food molecules into simple solutes.
• What are the steps for saliva preparation in the experiment?

  1. Rinse mouth with water.
  2. Collect 50-60 ml saliva by chewing paraffin.
  3. Add methylene blue to saliva for microscopic examination.
  4. Determine pH with pH paper.
  5. Filter the collected saliva.
• What is the first qualitative test performed on filtered saliva?

  Test for mucin using dilute acetic acid.
• How is the protein test conducted on saliva?

  By performing the Biuret test on 2 ml of saliva.
• What is the procedure to test for inorganic matter in saliva?

  Acidify saliva with HNO3, heat, filter, and test for chlorides, phosphates, sulfates, and calcium.
• How do you test for chlorides in saliva?

  Add 5 drops of AgNO3 to 5 drops of filtered saliva.
• What is the procedure for testing phosphates in saliva?

  Add (NH4)2MoO4 to saliva, warm, and observe for results.
• What is the test for sulfates in saliva?

  Add 5 drops of 0.1 M BaCl₂ to 5 drops of filtered saliva.
• How do you test for calcium in saliva?

  Add 5 drops of 0.1 M Na₂CO₃ to 5 drops of filtered saliva.
• What is the procedure for the Thiocyanate (Perch Test)?

  1. Add ferric chloride to saliva.
  2. Acidify with dilute HCl.
  3. Observe for red ferric thiocyanate precipitate.
  4. Add HgCl₂ to confirm the reaction.
• What are the steps for starch paste digestion using saliva?

  1. Add filtered saliva to starch paste.
  2. Test with iodine solution at 1-minute intervals.
  3. Note transparency and color changes.
  4. Apply Fehling’s test when achromatic point is reached.
• What indicates the completion of starch digestion in the experiment?

  The absence of blue color when iodine is added.
• What is the purpose of adding alcohol after observing erythrodextrin formation?

  To precipitate the products of salivary digestion.
• What is the procedure for separating the products of salivary digestion?

  1. Add saliva to starch paste and stir.
  2. Test with iodine after 5 minutes.
  3. Add alcohol when erythrodextrin is formed.
  4. Filter and evaporate the filtrate.
• How does free acid influence starch digestion?

  1. Prepare tubes with varying strengths of HCl.
  2. Add starch paste and saliva.
  3. Incubate at 40°C.
  4. Test with iodine and record observations.
• How does alkali influence starch digestion?

  1. Prepare tubes with varying strengths of Na₂CO₃.
  2. Add starch paste and saliva.
  3. Incubate at 40°C.
  4. Make solutions weakly acidic and test with iodine.
• What is the temperature maintained during the influence of free acid and alkali tests?

  40°C
• What is the purpose of adding acetic acid in the alkali influence test?

  To make each solution weakly acidic.
• What is alimentary digestion?

  Breaking down complex biomolecules into simpler substances
• What is required for the process of digestion?

  Presence of digestive enzymes
• What do catalysts do in biochemical reactions?

  Lower the activation energy needed for reactions
• What are hydrolytic enzymes also known as?

  Hydrolases
• What do hydrolytic enzymes do in digestion?

  Break down food into assimilable forms
• What enzyme is found in salivary juice?

  α-amylase
• What do hydrolytic enzymes catalyze the hydrolysis of?

  Proteins to amino acids
• What is the function of salivary juice?

  Contains enzymes that begin digestion
• What substrate does α-amylase act on?

  Starch
• What enzyme is found in gastric juice?

  Pepsin
• What is the role of intestinal juice?

  Contains finishing enzymes in the small intestine
• What does pancreatic juice contain?

  Lipase, α-amylase, trypsin, chymotrypsin
• What enzymes are found in intestinal juice?

  Maltase, sucrase, lactase, dipeptidase
• What is saliva primarily composed of?

  99% water
• What is the pH range of saliva?

  1. 5-7.5
• What is the function of mucin in saliva?

  Binds food particles and lubricates for swallowing
• How does pH affect enzyme action in digestion?

  Enzyme action depends on surrounding pH
• What happens to salivary amylase in the stomach?

  It is inactivated by acidic conditions
• What does the Biuret test indicate?

  Presence of proteins in a sample
• What is the test for mucin?

  Precipitated by adding dilute acetic acid
• What color indicates a positive Biuret test?

  Violet