Ncert Science Class 10 Solutions Chapter 5 Life Processes
Welcome to NCTB Solutions. Here with this post we are going to help 10th class students for the Solutions of NCERT Class 10 Science Book Chapter 5, Life Processes. Here students can easily find step by step solutions of all the questions in Life Processes. Also our Expert Science Teacher’s solved all the problems with easily understandable language with proper guidance so that all the students can understand easily. Here in this post students will get chapter 5 solutions. Here all Question Answer are based on NCERT latest syllabus.
Life Processes Exercise question Solutions :
(1) The kidneys in human beings are a part of the system for
Answer :
Correct option – (d) Excretion.
The excretory system of human beings includes a pair of kidneys, a pair of ureters, a urinary bladder and a urethra. The function of kidney is to remove urea and uric acid through urethra.
(2) The xylem in plants are responsible for
Answer :
Correct option – (a) Transport of water.
In xylem tissue, vessels and tracheids of the roots, stems and leaves are interconnected to form a continuous system of water-conducting channels reaching all parts of the plant, so the xylem in plants is responsible for transport of water.
(3) The autotrophic mode of nutrition requires
Answer :
Correct option – (d) All of the above.
Autotrophic is the process by which autotrophs take in substances from the outside and convert them into stored forms of energy. This material is taken in the form of carbon dioxide and water which is converted into carbohydrates in the presence of sunlight and chlorophyll.
(4) The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
Answer :
Correct option – (b) Mitochondria.
Breakdown of pyruvate using oxygen takes place in the mitochondria. Hence the answer is mitochondria.
(5) How are fats digested in our bodies? Where does this process take place?
Answer :
Carbohydrates, proteins, fats and all are digested in small intestine. Secreation of liver and pancreas are used for this purpose. Food from stomach is mostly acidic for enzymes and pancreas to act on it, it has to be made alkaline. Bile juice from liver is used for this purpose.
Fats in small intestine is present in the form of large globule, which is hard to process. Bile salts make it smaller, the pancreatic juice given by pancreas has enzymes like trypsin for protein digestion and lipase for breaking down emulsified fats. The glands are present in the wall of small intestine which secrets intestinal juice. The enzymes present in them finally convert proteins from amino acid, complex carbohydrates to glucose and fats into fatty acid and glycerol.
(6) What is the role of saliva in the digestion of food
Answer :
Naturally the food has to be processed to generate particles which are small and of the same texture. This is achieved by crushing the food with our teeth. Since the lining of the canal is soft, the food is also wetted to make its passage smooth.
When we eat something we like, our mouth ‘waters’. This is actually not only water, but fluid called saliva secreted by the salivary glands. Another aspect of the food we ingest is its complex nature. If it is to be absorbed from the alimentary Canal, it has to be broken into smaller molecules. This is done with the help of biological catalysts called enzymes. The saliva contains an enzyme called salivary amylase that breaks down starch which is a complex molecule to give simple sugar. The food is mixed thoroughly with saliva and moved around the mouth while chewing by the muscular tongue.
(7) What are the necessary conditions for autotrophic nutrition and what are its byproducts?
Answer :
Carbon and energy requirements of the autotrophic organism are fulfilled by photosynthesis. It is the process by which autotrophs take in substances from the outside and convert them into stored forms of energy. This material is taken in the form of carbon dioxide and water which is converted into carbohydrates in the presence of sunlight and chlorophyll. Carbohydrates are utilized for providing energy to the plant. We will study how this takes place in the next section. The carbohydrates which are not used immediately are stored in the form of starch, which serves as the internal energy reserve to be used as and when required by the plant.
(8) What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
Answer :
(1) Anaerobic respiration :
- It happens in absence of oxygen
- Pyruvate is converted into ethanol and carbon dioxide.
- This process takes place in cytoplasm.
- This process takes place in yeast during fermentation.
- It release less energy as compared to aerobic respiration
(2) Aerobic Respiration :
- It happens in presence of oxygen.
- It convert pyruvate into molecule of carbon dioxide and water.
- This process takes place in mitochondria.
- It release more energy than anaerobic respiration.
(9) How are the alveoli designed to maximise the exchange of gases?
Answer :
Within the lungs, the passage divides into smaller and smaller tubes which finally terminate in balloon-like structures which are called alveoli (singular–alveolus). The alveoli provide a surface where the exchange of gases can take place. The walls of the alveoli contain an extensive network of blood-vessels. As we have seen in earlier years, when we breathe in, we lift our ribs and flatten our diaphragm, and the chest cavity becomes larger as a result.
Because of this, air is sucked into the lungs and fills the expanded alveoli. The blood brings carbon dioxide from the rest of the body for release into the alveoli, and the oxygen in the alveolar air is taken up by blood in the alveolar blood vessels to be transported to all the cells in the body. During the breathing cycle, when air is taken in and let out, the lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released.
(10) What would be the consequences of a deficiency of haemoglobin in our bodies?
Answer :
In human beings, the respiratory pigment is haemoglobin which has a very high affinity for oxygen. This pigment is present in the red blood corpuscles. The deficiency creates irregular oxygen carrying in blood, which can cause anaemia, low blood pressure, fatigue, bad effect on immunity system and weight loss.
(11) Describe double circulation of blood in human beings. Why is it necessary?
Answer :
The heart is a muscular organ which is as big as our fist. Because both oxygen and carbon dioxide have to be transported by the blood, the hearth as different chambers to prevent the oxygen-rich blood from mixing with the blood containing carbon dioxide.
(12) What are the differences between the transport of materials in xylem and phloem?
Answer :
The difference between xylem and phloem are
Xylem :
- It moves water and mineral upwards.
- It only moves water in upward direction from root to all parts of body.
- transpiration helps water to move upward hence water requirement is fulfilled.
- It uses simple physical force.
Phloem :
- It transports soluble product of photosynthesis.
- it also transports amino acid and other substance.
- it transports in both direction upward as well as downward.
- It uses energy from ATP.
(13) Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.
Answer :
Alveoli in Lungs :
- Structure :
The passage divides into smaller tubes which create balloon-like structure called alveoli. The walls of alveoli contain an extensive network of blood vessels.
- Function :
Air is sucked into the lungs and fills the expanded alveoli. The blood brings carbon dioxide from the rest of the body for release into the alveoli, and the oxygen in the alveolar air is taken up by blood in the alveolar blood vessels to be transported to all the cells in the body. During the breathing cycle, when air is taken in and let out, the lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released.
Nephrons in the Kidneys :
- Structure :
A cluster of very thin-walled blood capillaries. Each capillary cluster in the kidney is associated with the cup-shaped end of a coiled tube called Bowman’s capsule that collects the filtrate. Each kidney has large numbers of these filtration units called nephrons packed close together. Some substances in the initial filtrate, such as glucose, amino acids, salts and a major amount of water, are selectively re-absorbed as the urine flows along the tube.
- Function :
The amount of water re-absorbed depends on how much excess water there is in the body, and on how much of dissolved waste there is to be excreted. The urine forming in each kidney eventually enters a long tube, the ureter, which connects the kidneys with the urinary bladder. Urine is stored in the urinary bladder until the pressure of the expanded bladder leads to the urge to pass it out through the urethra.
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