Science [3 Marks Each] QUE-ANS

No, a leaf from a potted plant kept in dark will not turn blue-black when tested for the presence of starch.
This is because all the stored starch would have been used up by the plant. No fresh starch would be synthesised by leaves due to non-availability of sunlight (i.e. no photosynthesis can occur, thus no food is prepared).

1. Transpiration
2. Photosynthesis
3. Storage of food

The leaves of tulsi, coriander, and China rose have reticulate venation, whereas maize, grass, and wheat have parallel venation. In leaves with reticulate venation, the veins are arranged in a net-like pattern. In parallel venation, the veins are arranged parallel to one another.

• Close look of these plants make it clear that these plants are not of the same type.
• Plants and are small and have soft and thin stem. These are called herbs.
• Plant has many branches arising from the base and its stem is thin but hard. It is a shrub.
• Plant is tall. Its stem is thick and hard, it is a tree.

Sepals, petals, stamens and pistil are the parts of a flower. Stamen is made up of anther and filament and it represents the male part of the flower. The female part of the flower is called the pistil. The basal, swollen part of the pistil is called the ovary which contains the ovules.

1. Transpiration.
2. On a bright sunny day.
3. The set-up must be airtight/polythene bag must be dry/ the twig must be fresh with 10-12 leaves.

Main functions of roots are:

1. Roots absorb water and minerals from soil for the other parts of the plants.
2. Roots hold the plant firmly to the soil.
3. Some roots transform to store food, e.g., radish.
4. Roots of leguminous plants contain symbiotic bacteria which add the fertility of soil by fixing atmospheric nitrogen into nitrates.

Boojho did not get the expected results in his experiment because he missed an important step in the procedure.
He did not boil the leaf in alcohol or spirit to remove chlorophyll (green colour) from the leaf. It is necessary to remove chlorophyll because it interferes with the test for starch. The decolourised leaf, on adding iodine turns blue-black, showing the presence of starch.

1. In the given figure:

1. Petiole.
2. Mid rib.
3. Lamina.
4. Vein.

2. The leaf has reticulate venation, the veins in leaf occur in an irregular way forming a net-like structure.
3. Grass leaves have parallel venation. The vein run parallel to each other on both sides of mid rib.

1. Root
2. Leaf
3. Flower
4. Stem

Yes, the stem of a plant can be compared with a street with two ways traffic because movement of substances occur in different directions in it.

1. It carries water and minerals from the roots to the leaves and other parts of plant in upward direction.
2. It takes the food prepared by the leaves to other parts of the plant, in downward direction.

The veins of leaves and their type of venation are: