CBSE Questions for Class 10 Biology Life Processes Quiz 3 - MCQExams.com

• Lymph nodes are the oval-shaped lymphatic organ scattered throughout the body and play an important role in the body's defense mechanisms. 
• It is majorly composed of WBC and devoid of RBC. 
• Lymph nodes do not perform the endocrine function.

Correct Option: A
Explanation:

• Excretion is an essential process in all forms of life. It is a process in which metabolic waste is eliminated from the body of an organism. Accumulation of these wastes beyond a level inside the body is harmful to the body of an organism.
• In mammals, urine is expelled with the help of the excretory system. In unicellular organisms, waste products are discharged directly through the surface of the cell.
• In green plants, excretory gases like carbon dioxide and oxygen exit the plant body through stomata, root cell walls, etc. They also eliminate waste materials in the form of resin, saps, latex, etc.
  

Correct Option: D
Explanation:

• The autotropic mode of nutrition is a process in which an organism produces its own food from raw materials.
• The raw material for photosynthesis is water and carbon dioxide. 
•  This process occurs in presence of sunlight, where chlorophyll which is a green-coloured pigment helps in the formation of oxygen and carbohydrate.
• Hence, in the autotropic mode of nutrition, it requires all of the above.

Cellular respiration is defined as a set of metabolic reactions and processes that take place in the cells of organisms. These reactions and processes convert chemical energy from oxygen molecules or nutrients into adenosine triphosphate (ATP) and then release waste products.

The glucose molecule is the primary fuel for cellular respiration. Without it, the entire process would not be able to start as there would be no pyruvate to initiate Kreb's cycle (second step in cellular respiration).

Hence, the correct answer is option C.

Blood pressure is the pressure of the circulating blood against the walls of the arteries, the veins, and the chambers of the heart. The blood pressure in the large artery of the heart, the aorta, and the other large arteries of a healthy adult is usually 120 mm Hg during the contraction of the heart (systole), and 80 mm Hg during relaxation of the heart (diastole). Normal blood pressure is less than 120/80 mm Hg. So, the correct answer is-120/80 mm Hg.

• A storage organ is a part of a plant modified for storage of energy (generally in the form of carbohydrates) or water. 
• Storage organs often grow underground, where they are protected from attack by herbivores. 
• Hence, A storage organ is a part of a plant modified for storage of energy generally in the form of Carbohydrates.
• So, the correct answer is 'Carbohydrates'.

• The mechanism of filtration of blood (1100-1200 ml) by the kidneys (nephrons) per minute is called ultrafiltration. 
• Reproduction is the biological process by which organisms produce young ones similar to themselves.
• Diffusion is the movement of substances from the region of the higher concentration to the area of lower concentration.
• Osmosis is the movement of solvent or water molecules from the region of their higher diffusion pressure to the region of their lower diffusion pressure through a semipermeable membrane.

• Humans have double circulation. The blood pumped by the right ventricle enters the pulmonary artery, whereas the left ventricle pumps blood into the aorta. 
• The deoxygenated blood pumped into the pulmonary artery is passed onto the lungs from where the oxygenated blood is carried by the pulmonary veins into the left atrium. 
• This pathway constitutes the pulmonary circulation. 

$$\textbf{Correct option: }$$ A

$$\textbf{ Solution: }$$

$$\textbf{ Option (A): }$$

$$\bullet$$The process of translocation in plants is defined as the movement of substances like amino acids and sucrose. 

$$\bullet$$This is a process which allows the relocation of the substances to happen in the internal body plant body. 

$$\textbf{ Option (B): }$$

$$\bullet$$Mimosa pudica is a sensitive plant which is also known as touch-me-not plant shows nastic movement caused by touch. 

$$\textbf{ Option (C): }$$

$$\bullet$$Chemotaxis is the movement of a motile cell or organism, in the direction of the increased concentration gradient of a particular type of substance. 

$$\textbf{ Option (D): }$$

$$\bullet$$Phototaxis is the orientation of free moving organisms towards the direction of light. 

Hence, the correct answer is option (A).

• The translocation of water and minerals in the xylary elements is always unidirectional, i.e., in the upward direction, from roots to aerial parts. 
• The driving force for transport in xylary elements is transpiration. 
• The translocation of organic solutes in phloem is bidirectional. 
• The transport of prepared food is from source to sink. 
• Wherever sugars are present in higher concentrations, from there, sugars will be transported to a region, where sugars are required or need to be stored.

• The lungs are large, paired, spongy organs present in the thoracic (chest) cavity. 
• The right lung is divided into three lobes, the left lung into two lobes. Because the lung consists largely of air tubes and elastic tissue, it is a spongy, elastic organ with a very large internal surface area for gas exchange. 
• Inside the lungs, the bronchi branch, becoming smaller and more in number. These branches give rise to more than 1 million tiny bronchioles in each lung. 
• Each bronchiole ends in a cluster of tiny air sacs, the alveoli. 
• Each human lung contains more than 300 million alveoli, which provide an internal surface area with the approximate size of a tennis court. 
• Each alveolus is lined by an extremely thin, single layer of epithelial cells.

In a normal human, the amount of blood pumped by the heart per minute is 5 litres. It can be calculated based on the heart rate which is defined as heartbeats per minute (72 beats a minute) and a stroke volume which is defined as the volume of blood pumped by one ventricle with each heartbeat (which is 70 ml per beat). Therefore, the average amount of blood pumped by the heart = 70*72 ml =~5 litres. 

Thus, the correct answer is option B.

• Humans have a four-chambered heart with complete separation between oxygenated and deoxygenated blood. 
• The right atrium receives deoxygenated blood from the upper and lower parts of the body.
• The right ventricle pumps deoxygenated blood to the lungs for oxygenation through the pulmonary artery. 
• Thus, the right atrium and the right ventricle are the chambers of the human heart that carry deoxygenated blood.
  Hence, Option B is correct.