What is the role of saliva in the digestion of food?
When we eat something we like, our mouth ‘waters'. This is actually not only water, but also a fluid called saliva secreted by the salivary glands. Another aspect of the food we ingest is its complex nature. If it is to be absorbed from the alimentary canal, it has to be broken into smaller molecules. This is done with the help of biological catalysts called enzymes. The saliva contains an enzyme called salivary amylase that breaks down starch, which is a complex molecule to give sugar. The food is mixed thoroughly with saliva and moved around the mouth while chewing by the muscular tongue.
What is the name of tiny projections on the inner surface of small intestine which help in absorbing the digested food ?
Name the process by which plant parts like roots, stems, and leaves get oxygen required for respiration.
Write correct sequence of four steps of method for the preparation of temporary mount of a stained leaf peel.
(a) Draw a diagram to show open stomatal pore and label on it:
(i) guard cells
(ii) chloroplast
(b) State two functions of stomata.
(c) How do guard cells regulate the opening and closing of stomatal pore?
(a) List the three events that occur during the process of photosynthesis.
Explain the role of stomata in this process.
(b) Describe an experiment to show that "sunlight is essential for photosynthesis."
(a) What is meant by breathing? What happens to the rate of breathing during vigorous exercise and why?
(b) Define translocation with respect to transport in plants. Why is it essential for plants? Where in plants are the following synthesised?
(i) Sugar (iii) Hormone
(a) Define a nutrient. Name four important nutrients present in our food.
(b) What are the various types of heterotrophic nutrition ?
(a) What is common for Cuscuta, ticks and leeches ?
(b) Name the substances on which the following enzymes act in the human digestive system :
(i) Trypsin (ii) Amylase (iii) Pepsin (iv) Lipase
(c) Why does absorption of digested food occur mainly in the small intestine ?
Name the final product/products obtained in the anaerobic respiration, if it takes place :
(a) in a plant (like yeast).
(b) in an animal tissue (like muscles).
State the three common features of all the respiratory organs like skin, gills and lungs.
What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
A Give one reason why multicellular organisms require special organs for exchange of gases between their body and their environment. :
(a) Name the pigment in leaves which absorbs sunlight energy.
(b) What is the colour of this pigment ?
(a) Define nutrition. Why is nutrition necessary for an organism ?
(b) What are the different modes of nutrition ? Explain with one example of each mode of nutrition.
(c) Name the mode of nutrition in (i) roundworm, and (ii) Plasmodium.
Describe the process of respiration in the following parts of a plant :
(a) Root (b) Stem (c) Leaves
In human alimentary canal, name the site of complete digestion of various components of food. Explain the process of digestion.
(a) Draw a diagram to show the nutrition in Amoeba and label the parts used for this purpose. Mention any other purpose served by this part other than nutrition.
(b) Name the glands associated with digestion of starch in human digestive tract and mention their role.
(c) How is required pH maintained in the stomach and small intestine?
Name the component of blood that helps in the formation of blood clot in the event of a cut.
Arrange the following processes involved in the nutrition in animals in the correct order (in which they take place):
Assimilation, Egestion, Ingestion, Absorption, Digestion
(a) Photosynthesis converts energy X into energy Y. What are X and Y ?
(b) State the various steps involved in the process of photosynthesis.
(a) How do guard cells regulate opening and closing of stomatal pores ?
(b) Two similar green plants are kept separately in oxygen free containers, one in dark and the other in continuous light. Which one will live longer ? Give reasons.
(a) What is photosynthesis ?
(b) Write a chemical equation to show the process of photosynthesis in plants.
(c) Explain the mechanism of photosynthesis.
(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 ?