Class 7 Science Chapter 1 MCQ

Symbiosis is an association between two different organisms that live together and help each other to survive, e.g. lichen (association between an alga and fungus).

The bodies of living organisms are made of tiny units called “cells”. Cells can be seen only under the microscope. Some organisms are made of only one cell. The cell is enclosed by a thin outer boundary, called the “cell membrane”.

Chlorophyll, sunlight, carbon dioxide and water are necessary to carry out the process of photosynthesis. During the process oxygen is released. The carbohydrates ultimately get converted into starch. The presence of starch in leaves indicates the occurrence of photosynthesis. The starch is also a carbohydrate.

Pitcher plant derives nutrition just the way any other plant does. It takes water and minerals from the soil and food by photosynthesis. But the soil in which it grows doesn’t has nitrogen so it uses the pitcher for killing small insects and then digesting them to derive nitrogen from the animal.

All mosquitoes breed in water. A mosquito during its life cycle passes through different modes of nutrition. The larva feeds on microorganisms. The Adult female feeds on blood to supply proteins for eggs and adults of both sucks feed on plant nectar. So, it is most appropriate to considered them as an omnivore.

Pitcher plant has modified leaves that help to trap insect to obtain nitrogen compounds. Thus, it is an insectivorous plant.

Saprophytic nutrition is scene in yeast, mushroom and bread mould. In this mode of nutrition, organisms obtain their food from dead and decaying organic matter. Such organisms are known as saprophytes.

Every plant gets their nutrients from soil. A pitcher plant smells good to trap insects when it lacks some nutrients which it fulfills by eating insects. Therefore, insects help in the enrichment of insectivorous plants like Pitcher Plant and Venus Flytrap. A pitcher plant feeds on insects to obtain essential nitrogen and amino acids.

The mode of nutrition is which organisms depend on other for their food is called heterotrophic nutrition. An organism that takes their food or nutrient from others, without giving anything in return, called “parasitic nutrition”. And the body in which he lives is called a “host” and they take nutrients from the body of host and gradually parasite harms them and possible causing death.

Chlorophyll makes plants green. Chlorophyll is located in a plant’s chloroplasts, which are tiny structures in a plant’s cells. It is basically a group of green pigments used by organisms that convert sunlight into energy via photosynthesis. Without this energy, plants would be unable to initiate the process of photosynthesis, which converts water and carbon dioxide into starches that plants can use for food.

Pitcher plant is an insectivorous plant that grow only in soils which do not contain sufficient nitrogen. These plants trap insects by various methods, kill them and digest then to obtain nitrogen compounds for their growth.

Chlorophyll, sunlight, carbon dioxide and water are necessary to carry out the process of photosynthesis. During the process oxygen is released. The carbohydrates ultimately get converted into starch. The presence of starch in leaves indicates the occurrence of photosynthesis. The starch is also a carbohydrate.

Carbon dioxide is the raw material of photosynthesis that is available in air. It is taken by the plant through the tiny pores, called stomata, present on the surface of leaves. The Other necessary conditions are the presence of water, chlorophyll and sunlight. (Oxygen is released during the process, hydrogen comes from water and nitrogen has no role in photosynthesis).

Yes, because the chlorophyll needed for photosynthesis is hiding within the leaf colour. Plant leaves contain chlorophyll as “Carotenoids” and “Anthocyanins”. These assist chlorophyll in the process of photosynthesis.

Phloem is the tissue in plants that transport food to the parts of the plant where it needs to go. Phloem is composed of various specialized cells called sieve tubes, companion cells, phloem fibres, and phloem parenchyma cells.

Stomata are the numerous small openings observed on the lower surface of a leaf. Each of these pores is surrounded by a pair of guard cells. The stomata help in the exchange of gases (CO2 goes in and O2 is released out).

Generally, leaves have a green pigment called chlorophyll which absorb the sunlight and makes food for the plant by the process of photosynthesis.

Chlorophyll is the green pigment present in leaves of plants that absorbs sunlight energy, to carry out photosynthesis. In the absence of chlorophyll, the leaves would not be able to capture sunlight energy. Therefore, no photosynthesis can occur.

Generally, leguminous plant such as gram, pulses. These plants have root nodules in them which have a symbiotic association with rhizobium bacteria. It converts nitrogen gases as compounds. In return, the plants provide food and shelter to the bacteria. Hence, farmers do not need to apply nitrogenous fertilizers in the field during cultivation.

A yellow tubular structures twining around the stem and branches of a tree. This is a plant called “Cuscuta” (Amarbel). It does not have chlorophyll. It takes readymade food from the plant on which it is climbing. As it deprives valuable nutrients, from the body of host. Hence, it is called a parasite.

When a goat eats all the leaves of a small plant. Still new leaves could be seen sprouting in the plant again. This is just because the small plant survived on the food stored in the stem and roots. It might have undergone gaseous exchange through lenticels on stem.

We see slimy, green patches in ponds or in other stagnant water bodies. These are generally formed by the growth of organisms called “algae”. They contain chlorophyll. Algae can also prepare their own food by photosynthesis, so they are known as “Autotrophs”. We have also seen fluffy patches of white, green, brown color growing on rotting wood during the rainy season. These organisms are called “fungi”. They take in nutrients in solution form from dead and decaying matter, called “Saprotrophs”.

A greenhouse is built of any material through which light can pass, such as glass or plastic. Farmers get many advantages like the crops grow well.

Carbohydrate in wheat to encourage the growth of yeast and other saprophytic fungi. They breakdown carbohydrates into simpler compounds like carbon dioxide and alcohol that leads to a foul smell.

Autotrophs are organisms that make food themselves from simple substances like water, CO2 in the presence of sunlight and chlorophyll, e.g. Green plants. Heterotrophs are organisms, which cannot make their own food and take in food prepared by the plants, e.g. Animals and humans Parasites are organisms, which live and derive nutrition from another organisms, called host, e.g. Cuscuta plant. Saprophytes are organism, which obtain nutrition from dead and decaying organic matter, e.g. Fungi, bacteria etc.