Life Processes: 10 CBSE Science Biology

Question: Name the following with reference to the alimentary canal:

1. (i) the largest gland.
   (ii) the gland that secretes digestive enzymes as well as hormones.
   (iii) the part where digested food is absorbed.
2. What are villi? Mention their function.

Answer:

1. (i) Liver  (ii) Pancreas  (iii) Small intestine
2. Numerous finger like projections present in the inner lining of the intestine which increase the surface area for absorption.

Function: It absorbs digested food in small intestine. Absorbs water in large intestine.

Question: List the three kinds of blood vessels of human circulation system and write their functions in tabular form.

Answer:

Question: Explain how the human body responds when adrenaline is secreted into the blood.

Answer: The heart beats faster, resulting in supply of more oxygen to our muscles. The blood to the digestive system and skin is reduced due to contraction of muscles around small arteries in these organs.

This diverts the blood to our skeletal muscles. The breathing rate increases because of the contraction of the diaphragm and the rib muscles.

Question:

1. Name the following:
   (i) part in which urine is produced
   (ii) part which stores the urine
   (iii) part which connects (i) and (ii)
   (iv) part from which urine is passed out.
2. Name the factors on which the amount of water reabsorbed along the tubular part of nephron depend on?

Answer:

1. (i) Kidney,  (ii) Urinary bladder, (iii) Ureter, (iv) Urethra
2. The amount of water reabsorbed depends on how much excess water there is in the body and on how much of dissolved waste there is to be excreted.

Question:

1. Name the following:
   (i) part where air is filtered by fine hair and mucus.
   (ii) part which terminates where exchange of gases takes place.
   (iii) balloon – like structures where exchange of gases takes place.
   (iv) part which separates chest cavity from abdominal cavity.
2. Why is the rate of breathing in aquatic organisms much faster than in terrestrial organism?

Answer:

1. (i) Nasal passage, (ii) Bronchioles, (iii) Alveoli, (iv) Diaphragm
2. Since the amount of dissolved oxygen is fairly low as compared to amount of oxygen in the air, the rate of breathing in aquatic organisms is much faster than that in terrestrial is much faster than that in terrestrial organisms.

Question: List in tabular form, three different between arteries and veins.

Answer: Arteries:

1. They carry blood from the heart to various organs of the body.
2. They have thick, elastic walls.
3. They do not have valves.

Veins:

1. They collect the blood from different organs and bring it back to the heart.
2. They have thin walls.
3. They have valves.

Question: Name three different glands associated with the digestive system in humans. Also name their secretions.

Answer:

Question:

1. Name the followings:
   (i) Organ which stores bile
   (ii) Organ which produces bile
2. Name one enzyme present in pancreatic juice and give its functions.
3. What are peristaltic movements?

Answer:

1. (i) Gall bladder, (ii) Liver
2. (i) Trypsin: Digest proteins into amino acids.
   (ii) Amylase: Digest carbohydrates into simple sugars.
   (iii) Lipase: Digest fats into fatty acids and glycerol.
3. The lining of alimentary canal has muscles that contract rhythmically in order to push food forward. These are known as peristaltic movements.

Question: Define nutrition? What are the different modes of nutrition?

Answer: Nutrition is the process of intake, as well as utilization of nutrients by an organism. The different modes of nutrition are saprophytic nutrition, parasitic nutrition and horologic nutrition.

Question: What is the mode of nutrition in fungi?

Answer: Saprophytic nutrition is the mode of nutrition that is seen in fungi.

Question: Name the pigment, which can absorb solar energy.

Answer: Chlorophyll is the pigment, which can absorb solar energy.

Question: Name the two stages in photosynthesis.

Answer: The two stages in photosynthesis are:

(i) Light reaction and
(ii) Dark reaction.

Question: Name the factors, which affect photosynthesis.

Answer: The factors which affect photosynthesis, are light, water, temperature, humidity, age of the leaf and carbon dioxide.

Question: Define a herbivore and a carnivore.

Answer: The animals that feed only on plants are called herbivores. The animals that feed only on flesh are called carnivores.

Question: How does amoeba engulf its food?

Answer: Amoeba engulfs its food by extending Pseudopodia. This process is known as Phagocytes.

Question: Name the parts of the digestive system of a grasshopper.

Answer: The parts of digestive system of a grasshopper are pharynx, salivary glands, hepatic caeca, malpighian tubules, ileum, colon, rectum and anus.

Question: What are the functions of the liver and the pancreas?

Answer: The liver secretes bile, which contains bile pigments and bile salts. The bile secreted by the liver cells is normally stored in the gall bladder, until needed in the duodenum. Pancreas lie parallel to and beneath the stomach. It is a large gland, which secretes digestive enzymes as well as the hormones, insulin and glucagons. Both bile and pancreatic juice enter duodenum through a common duct. Bile emulsifies fat present in the food. Pancreatic juice contains trypsin, for digesting proteins and pancreatic amylase for the breakdown of starch.

Question: Define breathing.

Answer: Breathing is a process by which organisms inhale oxygen. The inhaled oxygen gets diffused into the blood and the carbon dioxide from the blood diffuses back into the alveoli from where it is exhaled.

Question: How is respiration different from breathing?

Answer: Respiration is a complex process, which includes breathing, the mechanism of exchange of gases,oxygen and carbon dioxide and oxidation of digested food occurring in the cells in order to release energy. The main outcome of respiration is the release of energy through oxidation of simple food molecules such as glucose.

Question: In which kind of respiration is more energy released?

Answer: In aerobic respiration more energy is released.

Question:Which part of the roots is involved in exchange of respiratory gases?

Answer: Root hair is the part of the root which is involved in exchange of respiratory gases.

Question: What are (i) stomata and (ii) lenticels?

Answer:

1. Stomata are tiny apertures found on the surface of the leaf, which regulate the exchange of respiratory gases and transpiration.
2. Lenticels are the raised pores in the woody plants that allow the exchange of gases between the atmosphere and the internal tissues.

Question: Give two points of differences between respiration in plants and respiration in animals.

Answer: The respiration in plants differ from respiration in animals in two respects, they are

1. There is minimal transport of gases from one part of the plant to another, unlike the animals.
2. Plant respiration occurs at a much slower rate than animal respiration.

Question: Name the respiratory organs of

1. fish
2. mosquito
3. earthworm
4. dog

Answer: The respiratory organs of

1. fish – gills
2. mosquito – tracheoles
3. earthworm – skin
4. dog – lungs.

Question: From where do the following take in oxygen?
(i) prawn (ii) rat.

Answer:
(i) Prawns take in oxygen that is dissolved in water.
(ii) Rat takes in oxygen from the atmosphere.

Question: State the function of epiglottis.

Answer: Epiglottis prevents the food from entering into the trachea.

Question: Define photolysis.

Answer: The phenomenon of breaking down of water in the illuminated chloroplast is known as photolysis.

Question: What are the living organisms that cannot make their own food called?

Answer: The living organisms that cannot make their own food called heterotrophs.

Question: What are Chemotrophs?

Answer: Chemotrophs are organisms, which do not require light. They manufacture their food from inorganic substances in the presence of energy derived from the oxidation of simple inorganic compounds of iron, Sulphur etc.
e.g. bacterium Nitrosomonas.

Question: What is compensation point?

Answer: The compensation point is the amount of light on the light curve where the rate of photosynthesis exactly matches the rate of respiration.

At this point, the uptake of CO2 through photosynthetic pathways is exactly matched to the respiratory release of carbon dioxide, and the uptake of O2 by respiration is exactly matched to the photosynthetic release of oxygen. This point is reached during early mornings and late evenings.

Question: Other than chlorophyll, which other pigment is necessary for photosynthesis?

Answer: Carotenoids are the pigments, which are necessary for photosynthesis other than chlorophyll. Carotenoids are yellow, orange, red or brown pigments, which absorb sunlight and pass this energy on to chlorophyll for the purpose of photosynthesis. Thus, the Carotenoids themselves do not carry out photosynthesis but help in photosynthesis.

Question: Where does digestion begin?

Answer: Digestion begins from the mouth.

Question: What is the name given to the process of using the absorbed food for producing energy?

Answer: The name given to the process of using the absorbed food for producing energy is assimilation.

Question: What happens to visible light of the Sun when it falls on chlorophyll?

Answer: Visible light of the Sun consists of seven colors, namely, violet, indigo, blue, green, yellow, orange and red. Out of these lights of different wave lengths, chlorophyll absorbs mainly blue, violet, red and orange lights but does not absorb the green light. It is due to the reflection of green light by the chlorophyll that the plant looks green in colour.

Question: Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?

Answer: In multi-cellular organisms all the cells may not be in direct contact with the surrounding environment. Hence diffusion will not meet all the requirements of all the cells.

Question: What criteria do we use to decide whether something is alive?

Answer: Movement in response to external stimuli, breathing, growth etc.

Question: What are outside raw materials used for by an organism?

Answer: Outside raw materials are used for maintenance and sustenance of life by an organism.

Question: What processes would you consider essential for maintaining life?

Answer: All processes that perform the maintenance function of living organisms are called life processes. All life processes are essential for maintaining life.