Class 10 Science Chapter 6 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.

The first step is the break-down of glucose, a six-carbon molecule, into a three-carbon molecule called pyruvate. This process takes place in the cytoplasm.

Heterotrophs do not synthesise their own food. They feed on autotrophs for their nutrition.

Non-living things which are not alive cannot move by themselves. For example, a stone is a non-living thing which cannot move by itself from one place to another or show any other type of movement. We will have to move it by applying force from outside.

Energy is required by an organism even during sleep because when we are asleep a number of biological processes keep on occurring in the body which require energy. Our heart beats non-stop even when we are asleep to pump blood throughout the body. And this beating of heart requires energy. Thus, the working of heart requires are continuous supply of energy.

The solution turned blue-black in colour just because of starch.

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.

Nitrogen is an essential element used in the synthesis of proteins and other compounds. This is taken up in the form of inorganic nitrates or nitrites. Sometimes it is taken up as organic compounds i.e., urea, which have been prepared by bacteria from atmospheric nitrogen.

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

The summary equation of photosynthesis is: 6CO2 + 12H20+ Chlorophyll +Sunlight → C6H12O6 +6CO2 + 6H2O by using. Photosynthesis is a process by which green plants make their own food, e.g., glucose, CO2 and H2O in the presence of sunlight energy and chlorophyll in the presence of. Oxygen gas is released during the process of photosynthesis.

Oxygen-rich blood from the lungs comes to the thin-walled upper chamber of the heart on the left, the left atrium. The left atrium relaxes when it is collecting this blood. It then contracts, while the next chamber, the left ventricle, relaxes, so that the blood is transferred to it. When the muscular left ventricle contracts in its turn, the blood is pumped out to the body. De-oxygenated blood comes from the body to the upper chamber on the right, the right atrium, as it relaxes. As the right atrium contracts, the corresponding lower chamber, the right ventricle, dilates. This transfers blood to the right ventricle, which in turn pumps it to the lungs for oxygenation. Since ventricles have to pump blood into various organs, they have thicker muscular walls than the atria do. Valves ensure that blood does not flow backwards when the atria or ventricles contract.

In autotrophs, the cellular energy reserve is starch. However, carbohydrates serve as a major fuel in the cells to provide energy for life processes. The sugar (glucose) produced that is not used immediately gets stored in the form of starch in plants. In animals, food is stored in the form of glycogen. These food reserves provide energy as and when required by the organisms.

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

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

The human saliva contains an enzyme called salivary amylase, which breaks down the starch present in food into sugar. The digestion of starch (carbohydrates) begins in the mouth. In case, saliva is lacking, it will affect the break-down of starch. The protein digestion begins in the stomach by the enzyme pepsin and completes in small intestine by enzyme trypsin, chymotrypsin, carboxypeptidases, aminopeptidases and dipeptidases. The fats are broken down into small particles by bile in small intestine and then broken-down fatty acids and glycerol by lipases present in pancreatic juice. Absorption of vitamins takes place in the small intestine.

During the photosynthesis, the following steps take place: (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.

Arteries are the vessels which carry blood away from the heart to various organs of the body. Since the blood emerges from the heart under high pressure, the arteries have thick, elastic walls. Veins collect the blood from different organs and bring it back to the heart. They do not thick walls because the blood is no longer under pressure, instead they have valves that ensure that the blood flows in only one direction.

Living things can move by themselves. The plants are fixed in the soil at a place so they cannot move like animals from place to place but the plants can only move parts of their body such as leaves, flowers, roots etc.

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

The whole process of an aerobic respiration take place in the cytoplasm of cells.

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.

Pancreas secretes pancreatic juice which contain following: Digestive enzymes amylases, lipases, trypsin. Amylase breaks down the starch, trypsin digests the proteins and lipase breaks down the emulsified fats.

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 blue black colour of rice water confirms the presence of starch. No colour change will be seen in case of proteins fats in iodine solution colour, when iodine is added with them. Note: A starch solution on addition of iodine turns blue black in colour.