What is the role of saliva in the digestion of food?
When we eat something we like, our mouth â€˜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.
Name the factors, which affect photosynthesis.
Why is the rate of breathing in aquatic organisms much faster than in terrestrial organisms ?
Where does digestion begin?
Name the correct substrates for the following enzymes
(a) Trypsin (b) Amylase (c) Pepsin (d) Lipase
What are enzymes? Name any one enzyme of our digestive system and write its function.
List three characteristics of lungs which make it an efficient respiratory surface.
State two differences between arteries and veins.
Name two excretory products other than 02 and CO2 in plants.
(a) Draw a labelled diagram of the respiratory system of human beings with diaphragm at the end of expiration.
(b) List four conditions required for efficient gas exchange in an organism.
The leaves of a plant first prepare food A by photosynthesis. Food A then gets converted into food What are A and B ?
Name the green pigment present in the leaves of a plant.
Name the enzyme present in human saliva. What type of food material is digested by this enzyme ?
What is the name of the opening in the human body through which undigested food is thrown out ?
Where is digested food absorbed into blood in human body ?
What substances are contained in pancreatic juice ? What are their functions ?
(a) What is the role of hydrochloric acid in our stomach ?
(b) What is the function of enzymes in the human digestive system ?
(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.
Name one substance which is produced in anaerobic respiration by an organism but not in aerobic respiration.
What is the name of the extensions of the epidermal cells of a root which help in respiration ?
Name the organs of breathing in fish.
Where in the lungs does gas exchange take place ?
What is the name of tiny air-sacs at the end of smallest bronchioles in the lungs ?
What is the other name of wind-pipe ?
In the lungs :
(a) what substance is taken into the body ?
(b) what substance is removed from the body ?
Define breathing. State the differences between breathing and respiration.
Describe the process of respiration in the following parts of a plant :
(a) Root (b) Stem (c) Leaves
(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 ?
(a) Explain how, the air we breathe in gets cleaned while passing through the nasal passage.
(b) Why do the walls of trachea not collapse when there is less air in it ?
(c) How are oxygen and carbon dioxide exchanged in our body during respiration ?
(d) How are lungs designed in human beings to maximise the exchange of gases ?
Name the two stages in photosynthesis.
Give two points of differences between respiration in plants and respiration in animals.
Name the respiratory organs of
How are fats digested in our bodies? Where does this process take place?
Why do fishes die when taken out of water?
List in tabular form three differences between arteries and veins.
State the basic difference between the process of respiration and 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
In addition to carbon dioxide and water, state two other conditions necessary for the process of photosynthesis to take place.
What is the scientific name of the animals which are :
(i) only meat eaters ?
(ii) only plant eaters ?
(iii) both, plant and meat eaters ?
What substances enter into the food vacuole in Amoeba to break down the food ?
What is the name of tiny projections on the inner surface of small intestine which help in absorbing the digested food ?
(a) What criteria can be used to decide whether something is alive ?
(b) What is meant by life processes ? Name the basic life processes common to all living organisms which are essential for maintaining life.
a) How do plants obtain food ?
(b) Why do plants need nitrogen ? How do plants obtain nitrogen ?
Define (i) saprophytic nutrition (ii) parasitic nutrition, and (iii) holozoic nutrition. Give one example of each type.
(a) How does carbon dioxide from the air enter the leaves of a plant to be used in photosynthesis ?
(b) How does water from the soil reach the leaves of a plant to be used in photosynthesis ?
(a) Which part of the body secretes bile ? Where is bile stored ? What is the function of bile ?
(b) What is trypsin ? What is its function ?
Match the organisms given in column I with the processes given in column II :
Match the terms in column I with those in column II :
(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 ?
(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.
Where does the blood absorb oxygen in the human body ?