Morphology of Flowering Plants — BIOLOGY STD 11 Science — Question

Describe the role of different regions of a nephron in urine formation.

Succinic dehydrogenase is an enzyme that causes the substrate, succinate, to breakdown into fumarate.
Malonate is a substance that resembles succinate and inhibits the activity of succinic dehydrogenase.

1. State the type of inhibition of succinic dehydrogenase by malonate.
2. Explain how this type of inhibition affects the activity of the enzyme.

What is the significance of step-wise release of energy in respiration?

Compare the following:
Resting potential and action potential

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

Write an account on skeleton of sponges.

Biology teacher was teaching cell cycle in the class. She taught that cell is the basis from which life exists. Also explained well about cell cycle. Robin who was a bright student was facing difficulties in understanding the topic he reached home and asked her sister who is a student of biology in a college about details of cell cycle and cell theory. She explained him that according to cell theory, cells arise from pre-existing cells and the process involved is cell division. Sexually reproducing organisms start their life from a single cell, called zygote, and cell divisions do not stop with the formation of a mature organism, but continue throughout the life.

1. What is meant by cell cycle?
2. Which is the actual phase of cell division?
3. When (at what phase) do the cell organelles duplicate?
4. What values are reflected from the Robin's concern?

What is the need of a classification system in biology? How did different classification systems develop over a period of time?

According to the classification of enzymes ligases are one of the important class of enzymes. Explain it by giving example.