Body Fluids and Circulation — BIOLOGY STD 11 Science — Question

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?

Answer the following questions with reference to the anatomy of dicot stem

1. Type of cells present in the hypodermis.
2. Why is the endodermis layer referred to as starch sheath?
3. Why are the vascular bundles present here referred to as 'open' and 'conjoint'?

What is cardiac cycle? Write the difference between right ventricle and left ventricle.

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

Plants require water for their survival. But when watered excessively, plants die. Discuss.

Answer the following:
How many types of nephridia are found in earthworm based on their location?

Write the description of gynoecium in various plants.

What is photorespiration?

List out the important functions of connective tissue.

Explain the pelvic girdle of human skeleton.