PART - 1 - Unit III : CH - 8 Cell: The Unit of Life — BIOLOGY STD 11 Science — Question

Name two cell-organelles that are double membrane bound. What are the characteristics of these two organelles? State their functions and draw labelled diagrams of both.

Write the role of diaphragm and intercostal muscles in the inspiratory process.

Define the following. Draw a picture of the fruit mango and coconut.
1. Monoadelphous 2. Diadelphous 3. Polyadelphous 4. Epiphyllous

Write the function of the following in case of frog:

1. Tongue.
2. Pigment cells.
3. Vocal sacs.
4. Mucous glands.
5. Tympanic membrane.

The cells of a unicellular organism are usually spherical whereas those of multicellular tend to be many-sided. Why?

Akshita who is a biology tutor was teaching photosystems to the students at her place. While explaining the topic light reaction said that, "Two of the three products of light reaction, ATP and NADPH are used to drive the reactions in the biosynthetic/dark phase." It has been verified by the fact that immediately after light becomes unavailable, the biosynthetic phase continues for some time and then stops; if light becomes available again, the process continues.
Her brother, student of class XI was also listening the same and was remembering that he had listened the same from his biology teacher also. He interupped her sister and asked her to re-explain the whole process for the better understanding.

1. What are the products of light reaction?
2. Can we say that calling the biosynthetic phase, dark reaction is a misnomer? Justify.
3. Name the first stable product of photosynthesis.
4. What value you learn from this phenomenon if applied in daily life?

Describe the structure of the following with the help of labelled diagrams.
Nucleus

Elaborate on the following :
(i) Testes, (ii) Ovaries.

Stolon, offset and rhizome are different forms of stem modifications. How can these modified forms of stem be distinguished from each other?