Explain why, when air is taken in and let out during breathing, the lungs always contain a residual volume of air.
During the breathing cycle, when air is taken in and let out, the lungs always contain a certain residual volume of air so that there is sufficient time ‘for the oxygen absorbed’ into the blood and ‘for the carbon dioxide to be released’ from the blood.
What are the different ways in which glucose is oxidised to provide energy in various organisms ? Give one example of each.
Define (i) saprophytic nutrition (ii) parasitic nutrition, and (iii) holozoic nutrition. Give one example of each type.
(a) Photosynthesis converts energy X into energy Y. What are X and Y ?
(b) State the various steps involved in the process of photosynthesis.
State the three common features of all the respiratory organs like skin, gills and lungs.
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) Leaves of a healthy potted plant were coated with vaseline to block the stomata. Will this plant remain healthy for long? State three reasons for your answer.
(b) State any two differences between autotrophic nutrition and heterotrophic nutrition.
Name the intermediate and the end products of glucose breakdown in aerobic respiration.
Which of the following type of energy is used by living organisms to perform vital life processes ?
Kinetic energy, Chemical energy, Potential energy, Nuclear energy
What is the scientific name of the animals which are :
(i) only meat eaters ?
(ii) only plant eaters ?
(iii) both, plant and meat eaters ?
(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 ?
Name the substance whose build up in the muscles during vigorous physical exercise may cause cramps.
Name the areas in a woody stem through which respiratory exchange of gases takes place.
In the experiment "Light is essential for photosynthesis", why does the uncovered part of the leaf turn blue-black after putting iodine solution?
Fill in the following blanks with suitable words :
(a) All green plants are…………..
(b) All non-green plants and animals are…………
(c) Heterotrophs depend on…….. and other……………… for food,
(d) Green plants use……… ,………… and………… to make food.
(e) Iodine turns blue-black on reacting with………………
(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.
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?