Class 10 Science Chapter 6 MCQ

Yeast, mushroom and bread mould are saprophytes. They break down and convert complex organic molecules present in dead and decaying matter into simpler substances outside their body. These simpler substances are then absorbed by them, (i.e., saprotrophic nutrition). Green plants are autotrophic (make their own food through photosynthesis). Amoeba and Paramecium are holozoic (take solid or fluid organic food) and Cuscuta, lice, tapeworm are parasitic (live on food material obtained from the body of host).

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.

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.

Pyruvic acid is converted into lactic acid in the cytoplasm of muscles cells during deficiency of oxygen in human beings.

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.

Using the material in the form of carbon dioxide and water which is converted into carbohydrates in the presence of sunlight and chlorophyll. Carbohydrates are utilised for providing energy to the plant. 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.

Cells generally does not share the transaction of the particles or molecules.

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

The digestion of food completed in Small intestine. In large intestine only absorption of water take place. In mouth cavity the digestion starts only. In stomach, the digestion of proteins start in acidic medium with the help of pepsin.

Trypsin digests proteins in basic medium of food (pepsin digest proteins in acidic medium) and lipase emulsified fats.

Nostrils → pharynx → larynx → trachea → alveoli. The alveoli provide a surface where the exchange of gases can take place.

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.

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].

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

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.

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.

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.

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 opening and closing of the pore is a function of the guard cells. The guard cells swell when water flows into them, causing the stomatal pore to open. Similarly the pore closes if the guard cells shrink.

When we breathe in, we lift our ribs and flatten our diaphragm, the chest cavity becomes larger. Alveoli is balloon like structure which provides a surface where the exchange of gases occurs the walls of alveoli consist of network of blood-vessels. The air is sucked into the lungs to fill 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. 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 human lungs have millions of air sacs called alveoli whose surface area is many that of the body. These are involved in exchange of gases.

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

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

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.