Nokea
Four test tubes, each containing 2cm3 of amylase solution are treated as follows: 1 boiled, then cooled to 1 °C 2 boiled, then cooled to 25 °C 3 frozen, then warmed to 1 °C 4 frozen, then warmed to 25 °C 10 cm3 of starch solution were then added to each tube and after 5 minutes, 2 drops of iodine solution were added to each tube. Which row shows the results?
- A. 1: blue-black, 2: blue-black, 3: yellow-brown, 4: yellow-brown
- B. 1: blue-black, 2: yellow-brown, 3: blue-black, 4: yellow-brown
- C. 1: yellow-brown, 2: blue-black, 3: blue-black, 4: yellow-brown
- D. 1: yellow-brown, 2: yellow-brown, 3: blue-black, 4: blue-black
Correct Answer: A
Rationale: Boiling denatures the enzyme permanently, while freezing does not affect its activity once thawed.
You may also like to solve these questions
Endothelial cells of liver sinusoids, the following is true except:
- A. Lie on a discontinuous basal lamina
- B. Separated from hepatocytes by space of Disse
- C. The underlying space of Disse contain red blood cells
- D. The fenestra on its surface are collected at areas called sieve plates
Correct Answer: C
Rationale: The space of Disse contains plasma and microvilli, not red blood cells, which remain in the sinusoidal lumen.
A patient who has undergone gastrectomy (removal of the stomach) may suffer from:
- A. cirrhosis
- B. pernicious anemia
- C. gastric ulcer
- D. inability to digest fats
Correct Answer: B
Rationale: Gastrectomy can lead to pernicious anemia due to reduced intrinsic factor production, necessary for vitamin B12 absorption.
Crypts of Lieberkuhn are present in :-
- A. Intestine
- B. Stomach
- C. Oesophagus
- D. All of these
Correct Answer: A
Rationale: Crypts of Lieberkuhn are found in the small and large intestines.
Peristalsis moves food material:
- A. in the stomach and small intestine only
- B. in the small and large intestines only
- C. in the stomach and small and large intestines only
- D. from the pharynx to the anal canal
Correct Answer: D
Rationale: Peristalsis is a wave-like muscle contraction that moves food material through the entire gastrointestinal tract.
Which of the following choices leads to an elevation in stomach pH?
- A. Impairment of the mucous neck cells
- B. Heightened activity of G cells
- C. Suppression of parietal cells
- D. Excessive expression by chief cells
Correct Answer: C
Rationale: Suppression of parietal cells reduces HCl secretion, increasing stomach pH (making it less acidic).