(a) Name the main organs of the human digestive system. Also name the associated glands.
(b) How do carbohydrates, fats and proteins get digested in human beings ?
(a) The various organs of the human digestive system are mouth, oesophagus, stomach, small intestine and large intestine. The glands associated with the human digestive system are salivary glands, liver and pancreas.
(b) (i) Carbohydrates – The digestion of carbohydrates begins in the mouth. The human saliva contains an enzyme called salivary amylase which digests the starch present in the food into maltose sugar. The slightly digested carbohydrates when reaches the small intestine, pancreatic amylase present in the pancreatic juice breaks down the starch. The intestinal juice of the small intestine completes the digestion of carbohydrates and finally coverts it into glucose.
(ii) Fats – The process of digestion of fats begins in the stomach. The glands of stomach secrete a small amount of gastric lipase that breaks down the fats present in the food. From the stomach the partially digested food goes into small intestine where the pancreatic lipase breaks down the emulsified fats. The walls of small intestine secrete intestinal juice which converts the fats into fatty acids and glycerol.
(iii) Proteins – The digestion of proteins begins in the stomach. The glands of the stomach secrete gastric juice which contains an enzyme called pepsin. Pepsin converts the proteins into peptones. Pancreatic juice contains trypsin which digests the proteins into peptides and the intestinal juice completes the process of digestion of proteins thus converting it into amino acids.
What are the different ways in which glucose is oxidised to provide energy in various organisms ? Give one example of each.
(a) Draw a diagram of excretory system in human beings and label the following parts. Aorta, kidney, urinary bladder and urethra.
(b) How is urine produced and eliminated ?
Define (i) saprophytic nutrition (ii) parasitic nutrition, and (iii) holozoic nutrition. Give one example of each type.
Name the intermediate and the end products of glucose breakdown in aerobic respiration.
All the animals can be divided into three groups on the basis of their eating habits. Name the three groups.
What type of respiration takes place in human muscles during vigorous physical exercise ? Give reason for your answer.
Describe the process of respiration in State whether it is anaerobic respiration or aerobic respiration.
(a) What is meant by aquatic animals and terrestrial animals ?
(b) From where do the aquatic animals and terrestrial animals obtain oxygen for breathing and respiration ?
Give two points of differences between respiration in plants and respiration in animals.
What are the necessary conditions for autotrophic nutrition and what are its byproducts?
What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
Name the correct substrates for the following enzymes
(a) Trypsin (b) Amylase (c) Pepsin (d) Lipase
State the role of the following in human digestive system :
(i) Digestive enzymes (ii) Hydrochloric acid (iii) Villi
(a) What are heterotrophs ? Give one example of heterotrophs.
(b) What is the difference between autotrophic nutrition and heterotrophic nutrition ?
(a) Why is small intestine in herbivores longer than in carnivores ?
(b) What will happen if mucus is not secreted by the gastric glands ?
(c) What causes movement of food inside the alimentary canal ?
(a) What would happen if all the green plants disappear from the earth ?
(b) If a plant is releasing carbon dioxide and taking in oxygen during the day, does it mean that there is no photosynthesis occurring ? Justify your answer.
What are the differences between aerobic and anaerobic respiration ? Name some organisms that use anaerobic mode of respiration.
State the three common features of all the respiratory organs like skin, gills and lungs.