Plant Growth and Development — BIOLOGY STD 11 Science — Question

Many discoveries in science have been accidental. This is true for plant hormones also. Can you justify this statement by giving an example? Also what term is used for such accidental findings?

Define the term inflorescence. Explain the basis for the different types inflorescence in flowering plants.

Why biologists do not favour common names? Discuss briefly.

Sporozoans are parasitic protozoan protists which lack locomotory organelles atleast in trophozoite stage.

1. Where are they found?
2. What kind of nutrition they have?
3. Do they have nucleus?
4. What is the mode of reproduction?
5. List any four examples of sporozoans.

A sample of urine was diagnosed to contain high content of glucose and ketone bodies. Based on this observation, answer the following:

1. Which endocrine gland and hormone is related to this condition?
2. Name the cells on which this hormone acts.
3. What is the condition called and how can it be rectified?

Write one feature of sweet pea of each of following:

1. Flower onoman.
2. Calyx w ollen ZET.
3. Corolla onyo.
4. Androecium.
5. Gynoecium.
6. Fruit.

Give a brief account of structure and functions of Endoplasmic Reticulum.

A transverse section of a trunk shows alternate concentric rings

1. What are these rings known as?
2. How are these rings formed?
3. What is the significance of these alternate concentric rings?

OR
A transverse section of a stem of a tree shows concentric rings. How are these rings formed? Statethe significance of these rings.

Kritika's biology teacher explained the different phases of plant growth in her class. She taught that growth of plants takes place in three successive steps or phases from germination to maturation phase. Kritika reached home and asked her elder sister, a biology post-graduate student to clarify the phases in detail. Kritika's sister told her that she will explain the complete process with the help of experimentation. She took few seeds of pea and germinated them on a circular filter paper, soaked with water in a petri-dish. After two days of growth, she picked up a couple of seedlings with straight radicle and marked it from tip to base with the help of a waterproof ink and again placed the seedlings on moist filter paper to allow them to grow.

1. Mention different phases of growth in plants?
2. List the conditions required for growth.
3. What values are reflected from nature of Kritika's sister?

Cross pollination is necessary for bringing variations in plants; while self pollination does not bring variations. Find a similar statement from the following. Explain the benefits of cross pollination of ideas.

1. Inter-caste marriages are good for bringing cross-cultural assimilation; while same-caste marriages are not.
2. Interacting with people of different mindsets can enrich our thought, while sticking to interacting with like-minded people can stunt our mental development.
3. We should respect the feelings of all religions and cultures.