DIFFERENCES FROM PAST PAPERS (2002)

1. Rotation & Revolution Of Earth:

Rotation Of Earth:
i) it is the movement of the earth in which the earth makes rotation around its axis.
ii) Rotation of the earth occurs from West to East.
iii) The main effect of the rotation of the earth is the formation of days and nights.

Revolution Of Earth
i) it is the movement of the earth, in which the earth makes revolution around the sun.
ii) Revolution of the earth occurs in counter clockwise direction or from right to left.
iii) The main effect of the revolution of the earth is the change of seasons.

2. Dicot & Monocot Stem

Dicot Stem:
i) In dicot stem pericycle is broken.
ii) There are few vascular bundles.
iii) The vascular bundles are open.

Monocot Stem:
i) In monocot stem pericycle is not broken.
ii) there are many vascular bundles.
iii) The vascular bundles are closed.

3. Pollination & Fertilization (already described in paper 1995)

4. Penumbra & Umbra

Penumbra:
The term relates to the solar and lunar eclipse. When during its revolution, the moon comes between the sun and the earth then solar eclipse takes place. A shadow is created. The outer shadow region in the eclipse is called penumbra.

Umbra:
Similarly, when the solar eclipse takes place, two regions of shadow are created. Out of these the dark inner shadow region is called Umbra.

5. Nucleus & Nucleolus

Nucleus:
i) The nucleus is the main organelle.
ii) It is mostly present in the centre of the cell.
iii) It is membrane bound.
iv) The nucleus contains DNA.
v) It contains hereditary material in the form of chromosome and genes and controls all the activities of the cell.

Nucleolus:
i) The nucleolus is a sub-organelle.
ii) It is present in nucleus.
iii) It is non-membrane bound.
iv) It contains RNA.
v) It takes part in protein formation.