State the role of the following in human digestive system :
(i) Digestive enzymes (ii) Hydrochloric acid (iii) Villi
(i) Digestive enzymes – Foods need to be broken into their small or simpler
molecules so that they can be absorbed into the bloodstream. However, the physical breakdown of food is not enough. Enzymes are hence needed for the chemical breakdown of food and speeding up the digestive process. The products of digestion can hence be small enough to be absorbed.
(ii) Hydrochloric acid – Hydro chloric acid helps to kill the germs which might have entered in to the system through food. It creates acidic medium for the pepsin to act on food to breakdown proteins.
(iii) Villi – Villi are finger like projections in the small intestine. They help to increase the surface area for absorption of the digested food. Villi are richly supplied with blood vessel which help to absorb digested food in to the blood stream.
What is the name of tiny projections on the inner surface of small intestine which help in absorbing the digested food ?
State the three common features of all the respiratory organs like skin, gills and lungs.
(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 ?
Write correct sequence of four steps of method for the preparation of temporary mount of a stained leaf peel.
(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
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).
A Give one reason why multicellular organisms require special organs for exchange of gases between their body and their environment. :
Name the process by which plant parts like roots, stems, and leaves get oxygen required for respiration.
What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
Draw a neat diagram of excretory system of human beings and label on it:
(i) Left kidney (ii) Urinary bladder
Name the intermediate and the end products of glucose breakdown in aerobic respiration.
(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."
Arrange the following processes involved in the nutrition in animals in the correct order (in which they take place):
Assimilation, Egestion, Ingestion, Absorption, Digestion
What are the differences between aerobic and anaerobic respiration ? Name some organisms that use anaerobic mode of respiration.
(a)Explain how does the exchange of gases occur in plants across the surface of stems, roots and leaves.
(b) How are water and minerals transported in plants ?
In human alimentary canal, name the site of complete digestion of various components of food. Explain the process of digestion.
List the three kinds of blood vessels of human circulatory system and write ¦ their functions in tabular form.
(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?
Draw a neat diagram of excretory system of human beings and label the following:
(i) Kidney
(ii) Ureter
(iii) Urinary Bladder
(iv) Urethra
(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
Name the green dot like structures in some cells observed by a student when a leaf peel was viewed under a microscope. What is this green colour due to?
Name the component of blood that helps in the formation of blood clot in the event of a cut.
Apart from sunlight and chlorophyll, what other things are required to make food by photosynthesis ?