Question: Name the components of blood which transport:
- Food, carbon dioxide and nitrogenous wastes
Answer: (1) Plasma, (2) Hemoglobin
Question: When we breathe out, why does the air passage not collapse?
Answer: Because it is supported by cartilaginous rings which prevent its collapsing.
Question: Name the process of loss of water in the form of vapour from the aerial parts of the plants.
Question: Name the component of food that is not digested in the stomach.
Question: Name the stored food of animals.
Question: In which part of the digestive system is water absorbed?
Answer: Large intestine
Question: Which type of nutrition is present in tapeworm?
Answer: Heterotrophic nutrition
Question: Explain Holozoic nutrition.
Answer: The feeding of complex organic matter by ingesting, which is subsequently digested and absorbed is called holozoic nutrition e.g., amoeba, frog, human beings etc.
Question: The volume of glomerular filtrate produced is 18 L but the volume of urine excreted is just 1-2 L. Give a suitable reason for this statement.
Answer: It is because the remaining filtrate is reabsorbed in the kidney tubules.
Question: How does transportation of water occur at night in the absence of transpiration?
Answer: At night, transportation of water occurs due to the root pressure.
Question: How many chambers are present in the heat of fishes? How many times blood flows through heart during each cycle?
Answer: Two chambered.
Question: What role does bile play in digestion?
Answer: Emulsification of fats.
Question: How do autotrophs obtain CO2 and N2 to make their food?
- CO2 from atmosphere through diffusion of stomata.
- N2 is absorbed from soil in the form of nitrates and nitrites.
Question: Why rate of breathing in aquatic organisms is much faster than that seen in terrestrial organism?
Answer: Because the amount of dissolved oxygen is fairly low as compared to the amount oxygen in the air.
Question: Why ventricles have thicker walls than auricles?
Answer: Since ventricles have to pump blood into various organs, therefore, they have thicker muscular walls than the auricles.
Question: What is the function of platelet cells in bloods?
Answer: The platelet cells in blood circulate around the body and help to clot the blood at the point of injury.
Question: Where does digestion of fat take place in our body?
Answer: In the small intestine by the use of bile and Lipase.
Question: Name the organelle in which photosynthesis occurs.
Answer: Photosynthesis occurs in the green colored plastids called chloroplast.
Question: What are the raw materials used during photosynthesis?
(i) CO2 (from atmosphere)
(ii) Water (from soil)
Question: What is the main toxic waste kidney filters from the blood?
Answer: Urea or uric acid
Question: Name any two substances which are selectively reabsorbed from the tubules of a nephron.
Answer: Water, glucose, amino acids
Question: Give two functions of stomata.
Answer: (i) Exchange of gases (ii) Transpiration
Question: During breathing cycle, what is the advantage of residual volume of air in lungs? Explain.
Answer: So that there is sufficient time for oxygen to be absorbed and for CO2 to be released.
Question: Why do the walls of the trachea not collapse when there is less air in it?
Answer: Presence of rings of cartilage in the throat ensure that the air passage does not collapse.
Question: Mention the purpose of making urine.
Answer: The purpose of making urine is to filter out waste products (urea or uric acid) from the blood.
- Name the protein digesting enzyme present in pancreatic juice and the hormone secreted by pancreas.
- What is the function of pancreatic juice?
- (i) Name of Protein digesting enzyme: Trypsin
(ii) Hormone secreted by Pancreas: Insulin
- Pancreatic juice digests protein and fat.
Question: How are oxygen and carbon dioxide transported in human beings?
Answer: Hemoglobin present in the red blood cells takes up the oxygen from the lungs and carries it to the tissues. Carbon dioxide is more soluble in water than oxygen, hence it is mostly transported in the dissolved from in our blood and taken to the lungs where it is expelled out through the nostrils.
Question: Where do the following processes take place?
- Filtration of blood
- Reabsorption of glucose and water
- Secretion of salts to make final filtrate
- Collection of the final filtrate
- Renal tubules
- Tubular cells
- Collecting duct
Question: State in brief the function of:
- Renal artery
- Urinary bladder
- Renal artery: It brings blood to the kidney for filtering waste.
- Kidney: It filters the blood and forms urine.
- Ureter: It passes urine from kidneys to urinary bladder.
- Urinary bladder: It stores the urine until it is released through the urethra.
Question: Name the two glands associated with the digestive system in humans. Name their secretion also.
- Gastric glands: These are present in the walls of stomach. These release HCl, a protein digesting enzyme called pepsin and mucus.
- Pancreatic enzymes: The pancreas secretes pancreatic juice which contains enzymes like Trypsin for digesting proteins and Lipase for breaking down emulsified fats.
Question: What are the common features of the respiratory organs in aquatic and terrestrial animals?
- Large surface area
- Thin walled
- Richly supplied with blood
- Well protected