Life Processes - MCQ Test (22-11-2017) - Class 10 MCQ

Breathing is rhythmic. It is the intake of oxygen and expulsion of carbon dioxide. Respiration is the production of energy in the body, which includes breathing, mastication etc. Through this process, oxygen is inhaled. This inhaled oxygen is used to burn/oxidize/break down the food (glucose). This reaction produces energy which is used to carry out various activities going in our body. Our body needs continuous supply of energy to carry out these activities. So, respiration is a continuous process which makes us able to meet energy demands of our body. If respiration comes to halt the person will die.

Nitrogen is a component of amino acids and urea. Amino acids are the building blocks of all proteins. So, N is essential for the formation of protein.

There are several pigments found in the leaves of the plants. One of the major is Chlorophyll, Green in colour and is the pigment primarily responsible for photosynthesis. While Carotene and Xanthophyll are types of plant pigments that play a role in the metabolism of plants. Xanthophylls are the yellow pigment of the leaves and are classified as accessory pigments which absorb the wavelength that chlorophyll cannot absorb.

The presence of lamellae greatly increases the surface area of the gills, meaning that a large amount of water is available for gaseous exchange at any particular moment of time. In active fish, such as the Atlantic Mackerel (Scomber scombrus), which has nearly the same gill dimensions as the Atlantic Herring, there may be as much as 1,000 square mm of lamellae surface for every gram of body weight. Such a fish weighing 1 kg will have approximately 1 square metre of gill surface area.

Unlike plants, which use carbon dioxide and light as sources of carbon and energy, respectively, fungi meet these two requirements by assimilating preformed organic matter; carbohydrates are generally the preferred carbon source. As fungi grow on land and obtain their nutrients from dead organic matter, Thatswhy, Mode of nutrition in fungi is saprotrophic.

Wind velocity doesn't affect the photosynthesis. Unlike light intensity, CO₂ concentration, and temperature which are the major factors influencing the rate of photosynthesis, the wind has no effect on the reactions and the rate of reactions going in the chloroplast of the leaves of the plant.

Gizzard is the a muscular, thick-walled muscular pouch in the lower part of grasshopper's stomach. It is also present in many birds and reptiles and serves one single purpose of grinds food with chittinous plates, i.e, the breaking down of the food.

Milk is converted into curd or yogurt by the process of fermentation. Milk consists of globular proteins called casein. The curd forms because of the chemical reaction between the lactic acid bacteria and casein. During fermentation, the bacteria use enzymes to produce energy (ATP) from lactose. The byproduct of ATP production is lactic acid. Lactic acid acts on the globular proteins present in the milk and denatures them. This denaturation destroys the tertiary and quaternary structures of proteins and the globular proteins are converted into fibrous proteins thus giving a thick texture to the milk due to coagulation of the proteins.

The plastid is a major double-membrane organelle found in the meristematic tissues especially inside parenchyma cells of the plants or leaves, and the Parenchyma is present inside the central leaf or mesophyll

Carbon dioxide and nitrogen wastes transported through blood by dissolving in plasma in water soluble simpler molecular form, as CO₂ can dissolve with the nitrogen wastes or bind easily with the plasma proteins.

A tadpole lives under water so it only has one way of gas exchange (through the gills). First, the tadpoles open their mouth to let water enter. Then, the water moves into the gills which contain small membranes called lamella.

Photosynthesis and cellular respiration are complementary reactions. Cellular respiration is the process by which most cells make energy. The products of photosynthesis, oxygen and glucose, are the reactants of the cellular respiration reaction.

Saliva contains the enzyme amylase, also called ptyalin, which is capable of breaking down starch into simpler sugars such as maltose and dextrin that can be further broken down in the small intestine. Only about 30% starch digestion takes place in the mouth cavity.

Renal vein contains less nitrogenous waste as Renal artery brings oxygenated blood to the kidneys from the aorta which arises out of heart, Pulmonary artery and vein also carries blood from heart to lungs and lungs to heart respectively but this blood is not pure and has nitrogenous waste in it while renal vein carries deoxygenated but filtered blood to the heart from where it is again pumped to the entire body.

In cellular respiration, an organism oxidises glucose (i.e., combines it with oxygen) so as to form the energy-rich compound known as Adenosine Triphosphate (ATP). ATP, critical to metabolism (the breakdown of nutrients to provide energy or form new material), is the compound used by cells to carry out most of their ordinary functions. Among those functions are the production of new cell parts and chemicals, the movement of compounds through cells and the body as a whole, and growth.

Iron (Fe) atom is present in Fe²⁺ or Fe³⁺ oxidation states in the centre of porphyrin ring of 'heme' group.The heme group (a component of the hemoglobin protein) is a metal complex, with iron as the central metal atom, that can bind or release molecular oxygen.

6 CO₂ + 12 H₂O + light → C₆H₁₂O₆ (Glucose) + 6 H₂O + 6 O₂ (In presence of sunlight and chlorophyll)
In photosynthesis, CO₂ is reduced to glucose using electrons gained from the oxidation of water.
When water gets split into ions (H⁺ and OH^-) then hydrogen added to associated electrons of CO₂ to form a carbohydrate. So by gaining electrons, the CO₂ is reduced. The 6 O₂ at the end of the reaction are from water, water lost electrons in the process so it is oxidized.

Riya can receive blood from both Ayush and Ishoo as her blood type is AB and she can receive blood from types A, B, AB and O (AB is the universal recipient: recipients with AB blood are compatible with any other blood type).

Glycolysis involves the breaking down of a sugar (generally glucose, although fructose and other sugars may be used) into more manageable compounds in order to produce energy. The net end products of glycolysis are two Pyruvate, two NADH, and two ATP.

Osmoregulation is the active regulation of the osmotic pressure of an organism's body fluids to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration of electrolytes (salts in solution) to keep the fluids from becoming too diluted or concentrated.

Vestigial organs can be defined as an organ that once was useful in an animal's evolutionary past, but that now is useless or very close to useless. As vermiform appendix plays no significant function in humans, so it is considered as a vestigial organ.

Thromboplastin is a complex enzyme that is found in brain, lung, and other tissues and especially in blood platelets and that functions in the conversion of prothrombin to thrombin in the clotting of blood—called also thrombokinase.

The compounds oxidised during the process of respiration are called respiratory substrates. Carbohydrates, especially glucose, act as respiratory substrates.

The sieve tubes, the companion cells and the phloem parenchyma represent the living components of the tissue while phloem fibres represent the only nonliving component of the tissue. Phloem is commonly described as a living, complex permanent tissue.

Aerobic cell respiration (glycolysis + the Krebs cycle + respiratory electron transport) produces 36 ATP/glucose consumed. Aerobic cell respiration is roughly 18 times more efficient than anaerobic cell respiration. Your cells require a lot of energy and are dependent on the high efficiency of aerobic respiration.

Sunlight first activates chlorophyll and thus the chlorophyll become excited and it releases high energy rich electron and thus the chlorophyll become electron deficient. This electron deficient chlorophyll for getting it's electron thus splits the water to release hydrogen ion and hydroxyl ion.

Bile or gall is a dark green to yellowish brown fluid, produced by the liver of most vertebrates, that aids the digestion of lipids in the small intestine. In humans, bile is produced continuously by the liver (liver bile), and stored and concentrated in the gallbladder (gallbladder bile).

Green plants make their own food by the process of photosynthesis. Chlorophyll, the green pigment found in chloroplasts, traps light energy from the sun. The plant also takes in raw materials from the environment, water through its roots and carbon dioxide moves into the stomata by diffusion.

The first step of photosynthesis is the excitation of electrons of chlorophyll. The energy from the sun, raises an energy level in the chlorophyll molecule, causing electrons to leave the molecule and travel along the electron transport chain (ETC) in a series of oxidation and reductions.

Cellular Respiration is divided into two series of biochemical reactions: anaerobic and aerobic reactions. Anaerobic reactions occur in the cytoplasm of the cell and aerobic reactions occur in the mitochondria of the cells.