Explain the process of nutrition in Amoeba.
The mode of nutrition in amoeba is Holozoic, and the process of obtaining food by amoeba is called phagocytosis. The different processes involved in the nutrition of amoeba are:
(i) Ingestion: Ingestion is the process of taking food in the body. Amoeba is a unicellular animal, so it doesn't have a mouth for ingestion of food. Amoeba ingests the food by encircling it by forming pseudopodia. When the food is completely encircled, the food is engulfed in the form of a bag called food vacuole.
(ii)Digestion: Digestion is the process of breaking the large and insoluble molecules in small and water soluble molecules. In amoeba, several digestive enzymes react on the food present in the food vacuoles and break it down into simple and soluble molecules.
(iii) Absorption: The food digested by digestive enzymes is then absorbed in the cytoplasm by the process of diffusion. While the undigested food remains in the food vacuole. If a large amount of food is absorbed by amoeba, the excess food is stored in the cytoplasm in the form of glycogen and lipids.
(iv) Assimilation: During this step the food absorbed by the cytoplasm is used to obtain energy, growth and repair. This process of utilizing absorbed food for obtaining energy, repair and growth is called assimilation.
(v) Egestion: When sufficient amount of undigested food gets collected in the food vacuole, it is thrown out of the body by rupturing cell membrane. The process of removal of undigested food from the body is called egestion.
(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 ?
Name the following :
(a) The process in plants which converts light energy into chemical energy.
(b) Organisms that cannot prepare their own food.
(c) Organisms that can prepare their own food.
(d) The cell organelle where photosynthesis occurs.
(e) The cells which surround a stomatal pore.
(f) An enzyme secreted by gastric glands in stomach which acts on proteins.
State whether the following statements are true or false :
(a) During respiration, the plants take C02 and release 02.
(b) Energy can be produced in cells without oxygen.
(c) Fish and earthworm exchange gases during respiration in the same way.
Apart from sunlight and chlorophyll, what other things are required to make food by photosynthesis ?
State the three common features of all the respiratory organs like skin, gills and lungs.
A Give one reason why multicellular organisms require special organs for exchange of gases between their body and their environment. :
What is the name of tiny projections on the inner surface of small intestine which help in absorbing the digested food ?
What are the different ways in which glucose is oxidised to provide energy in various organisms ? Give one example of each.
What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
(a) Draw a sectional view of the human heart and label on it – Aorta, Right ventricle and Pulmonary veins.
(b) State the functions of the following components of transport system:
(i) Blood (ii) Lymph
(a) What are heterotrophs ? Give one example of heterotrophs.
(b) What is the difference between autotrophic nutrition and heterotrophic nutrition ?
(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) Leaves of a healthy potted plant were coated with vaseline. Will this plant remain healthy for long ? Give reason for your answer.
(b) What will happen to the rate of photosynthesis in a plant under the following circumstances ?
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).
What is the name of those cells in the leaf of a plant which control the opening and closing of stomata?
(a) Define a nutrient. Name four important nutrients present in our food.
(b) What are the various types of heterotrophic nutrition ?
a) How do plants obtain food ?
(b) Why do plants need nitrogen ? How do plants obtain nitrogen ?
(a) What is the role of hydrochloric acid in our stomach ?
(b) What is the function of enzymes in the human digestive system ?