Class 10 Science Chapter 5 MCQ

It is incorrect as; autotrophs can convert carbon dioxide and water into carbohydrates only in the presence of sunlight. The autotrophs contain the green pigment called chlorophyll which is capable of trapping sun energy. This trapped energy is utilised by them to make food by combining inorganic materials like CO2 and H2O by the process of photosynthesis. The food that is not used immediately, is stored in the form of starch. These autotrophs constitute the first trophic level in food chains.

Food comes first in Mouth and then moves through Oesophagus and stomach → small intestine → large intestine.

The blood leaving the tissues becomes richer in Carbon Dioxide. Because tissues receive the oxygenated blood from arteries and used up the oxygen to take energy and release the carbon dioxide.

Lactic acid is produced in the muscle from the metabolism of carbohydrate in the cells. When muscles work hard (as during the time of exercise), the ament of O2 needed is used during energy production. Thus O, lacks in the muscles. This results to another process called anaerobic metabolism. The product of this process of obtaining energy by anaerobically is lactic acid which is build up in muscles caused pain. However, lactic acid produced helps in healing process actually.

Fermentation is a form of anaerobic respiration. Pyruvate can be converted into ethanol and CO, in yeast during fermentation. Since this process takes place in the absence of air (oxygen), it is called anaerobic respiration. It takes place in cytoplasm. Break down of pyruvate using oxygen, i.e., aerobic respiration takes place in the mitochondria.

The digestion in stomach is taken care of by the gastric glands present in the wall of the stomach. These release hydrochloric acid, a protein digesting enzyme called pepsin and mucus. The mucus protects the inner lining of the stomach from the action of the acid under normal conditions.

Organisms which can make their own food from carbon dioxide and water are called autotrophs. Carbon dioxide and water are inorganic substance. So, we can say that, those organisms which can make their own food from the inorganic substances present in the environment are called autotrophs. All the green plants are autotrophs.

Here, all the statements are correct. Hence your answer will be option [D].

Green plants are autotrophic and synthesize their own food by the process of photosynthesis. The process of photosynthesis can be represented as: 6CO2 + 6 H2O + Sunlight + Chlorophyll → C6H12O6 + 6O2 (releases)

Carbon dioxide is used in photosynthesis for the products on of food. The oxidation of carbon compounds occurs in respiration.

Chloroplast are the organelles in the cells of green plants which contain chlorophyll and where photosynthesis take place. Thus, photosynthesis occurs in the organelles called the chloroplast present in the photosynthetic cell or mesophyll cell of green plants. In the other words, the site of photosynthesis in cell of the leaf are chloroplast. Chloroplast can be seen easily by using a light microscope.

A cell is the basic structural and functional unit of a living being. Each cell is made up of molecules. The molecules exhibit movement during cellular reactions that lead to life activities but their movements of molecules do not take place in the cells. The growth of a living organism starts with the division of its cells. All living things have an organised structure, which if breaks down leads to various diseases, disorders and even death. Therefore, the living things have to repair and maintain their structures through various processes. These life processes require energy which is obtained from food.

Here, all the statements are correct. Hence your answer will be option [D].

The blood leaving the tissues becomes richer in CO2. The main artery (aorta) carries oxygenated blood to all the organs of the body from the heart. When the oxygenated blood passes through the capillaries of the body organs/tissues, it gives oxygen to the body cells. At the same time, carbon dioxide produced during respiration enters into blood. Thus, deoxygenated blood (carrying CO2) leaves the tissues and enters the vena cava, from where they are again passed to the lungs for oxygenation.

Oxygen liberated during photosynthesis comes from water. The following events occur during photosynthesis (i) Absorption of light energy by chlorophyll. (ii) Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen. (iii) Reduction of carbon dioxide to carbohydrates, which is used as food for plants

Hippocampus, Exocoetus, Anabas. Because the rate of energy required for the body activities is very low.

Pisces have only two chambers to their hearts, and the blood is pumped to the gills, is oxygenated there, and passes directly to the rest of the body. Thus, blood goes only once through the heart in the fish during one cycle of passage through the body.

In Pisces (fishes), the heart is 2 chambered oral pumps deoxygenated blood to the gills, where oxygenation takes place by diffusion. The oxygenated blood from the gills is supplied to the body parts where oxygen is utilised and CO2 enters it making the blood deoxygenated. This deoxygenated blood returns to the heart. Thus, it has single circulation, i.e., blood passes through the heart only once during one complete cycle.

Valves ensure. that blood does not flow backwards when the atria or ventricles contract. Since ventricles have to pump blood into various organs with high pressure, they have thicker walls than atria. The separation of the right side and left side of heart by valve also helps to keep oxygenated and deoxygenated blood from mixing so as to supply high amount of oxygen to the body.

Left ventricle pumps oxygenated blood to different body parts while right ventricle pumps deoxygenated blood to lungs. Whereas right atrium receives deoxygenated blood from different parts of the body while left ventricle pumps oxygenated blood to different parts of the body. Hence, Deoxygenated blood flows through the right side of the heart. Oxygenated blood flows through the left side of the heart.

When we eat something a fluid called saliva secreted by the salivary glands. The saliva contains an enzyme called salivary amylase that breaks down starch which is a complex molecule to give simple sugar.

Here, all the statements are correct. Hence your answer will be option [D].

Carbon dioxide gas turns limewater milky. When air is blown from mouth into test, the lime water turns milky because the air we breathe out has more CO2.

Generally, the normal blood pressure values are: Systolic pressure: 120 mm Hg Diastolic pressure: 80 mm Hg This is usually written as 120 by 80.

The small intestine in human beings is the site of complete digestion of food. It is also the main region for absorption of digested food. However, digestion begins in the mouth cavity, food is further digested in the stomach to form a semi-solid paste. The undigested food from small intestine passes into large intestine that absorb most of the water.