In human digestive system the enzymes pepsin and trypsin are secreted respectively by :
Pancreas and liver
Pancreas and gall bladder
Stomach and pancreas
Stomach and salivary glands
(3)
Pepsin enzyme is secreted by the stomach that breaks down proteins into smaller amino acids. Trypsin enzyme is secreted by the pancreas that breaks down proteins
Which of the following is the correct statement regarding bile ?
Secreted by bile duct and stored in liver
Secreted by liver and stored in bile duct
Secreted by liver and stored in gall bladder
Secreted by gall bladder and stored in liver
(3)
Bile juice is secreted by the liver and stored in gall bladder. It helps in the breakdown of fats into fatty acids
Which of the following components of our food is digested by an enzyme which is present in saliva as well as in pancreatic juice ?
Proteins
Fats
Minerals
Carbohydrates
(4)
Salivary amylase, which is present in saliva, digests carbohydrates such as starch. It is also digested in the pancreas by pancreatic juices.
Where are proteins first digested in the alimentary canal ?
Small intestine
Oesophagus
Stomach
Mouth
(3)
Proteins are first broken down in the stomach. Pepsinogen is released by peptic cells in the stomach. Pepsinogen is a proenzyme which is converted into active pepsin. Pepsin breaks down proteins into smaller polypeptides.
Which is the first enzyme to mix with food in the digestive tract ?
Amylase
Pepsin
Trypsin
Cellulase
(1)
Amylase is the first enzyme in the digestive tract to mix with food. It is secreted in the mouth and acts on starch to break it down into smaller molecules.
Which of the following statements are correct ?
(i) Pyruvate can be broken down into ethanol and carbon dioxide by yeast.
(ii) Fermentation takes place in aerobic bacteria.
(iii) Fermentation takes place in mitochondria.
(iv) Fermentation is a form of anaerobic respiration.
(i) and (iii)
(ii) and (iv)
(i) and (iv)
(ii) and (iii)
(3)
Fermentation is an anaerobic process in which sugar is converted to acids or alcohol in the absence of oxygen. This process occurs in yeast, bacteria, and oxygen-depleted muscle cells in the same way that lactic acid fermentation does, but it takes place in the cytoplasm rather than in the mitochondria.
Choose the correct statements that describe arteries
They have thick elastic walls, blood flows under high pressure, collect blood from different organs and bring back to heart.
They have thin walls with valves inside, blood flows under low pressure, carry blood away from the heart to various organs of the body.
They have thick elastic walls, blood flows under low pressure, carry blood from the heart to various organs of the body.
They have thick elastic walls without valves inside, blood flows under high pressure and carry blood away from the heart to different parts of the body.
(4)
Arteries are thick-walled blood vessels that pump blood away from the heart at a high pressure because their walls are highly muscular, they do not have valves.
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in :
Cytoplasm
Mitochondria
Chloroplast
Nucleus
(2)
Aerobic respiration is the process of breaking down pyruvate into carbon dioxide, energy, and water in the presence of oxygen. This process takes place in the mitochondria of the cell.
When air is blown from mouth into a test tube containing lime water, the lime water turns milky due to the presence of :
Oxygen
Nitrogen
Carbon dioxide
Water vapour
(3)
Calcium hydroxide solution is the lime water. When it reacts with carbon dioxide, it forms insoluble calcium carbonate, which remains suspended in water and gives it a milky white colour.
During deficiency of oxygen in tissues of human beings pyruvic acid is converted into lactic acid in :
Cytoplasm
Chloroplast
Mitochondria
Golgi body
(1)
The pyruvate produced during glycolysis usually enters the Kreb’s cycle as acetyl coenzyme A in the mitochondrial matrix, where it provides a reservoir of chemical energy (ATP, NADH and). Pyruvic acid can be transformed to lactic acid as one of its potential fates in cellular respiration. Under stressful conditions, this often occurs in the cytoplasm of muscle tissue.
