Neural Control and Coordination — BIOLOGY STD 11 Science — Question

Amrita while playing with her friend, near the pond noticed in the pond that a green colour covering is floating on the surface of the water. She discussed this with her friend and both got surprised. Next day in the school Amrita asked her teacher about the same. Teacher told her, that was nothing, but green algae which occur both in fresh and marine water habitats.

1. Mention the economic importance of algae.
2. Why green algae are considered to be the ancestors of all land plants. Justify the statement by giving reasons.
3. What values as a good biology student are reflected from Amrita's character.

Define the following:

1. Respiration.
2. Respiratory substrate.
3. How does a tree trunk exchange gases with the environment although it lacks stomata?
4. Which is the most important energy carrier? Is this compound mobile?
5. Name the major respiratory substrates used by most organisms. It unavailable at time, what other substances can be used for respiration?

What is the benefit of cell walls, in plant cells?

Eukaryotic cell have organelles which may
bound by a double membrane.
Group the various sub-cellular organelles into these categories.

Proteins have been called 'biological polymers'.Explain.

An abnormal type of secondary growth is called anomalous secondary growth.

1. In which plants it occur?
2. How does it occur?

Compare the following:
Central neural system (CNS) and Peripheral neural system (PNS)

Which vascular system is found in humans? Write any three importance of this system.

What is meant by development in plants? Represent schematically the processes in the development of a plant cell.

Differentiate between nucleosides and nucleotides. Give one example for each.