Photosynthesis in Higher Plants — BIOLOGY STD 11 Science — Question

Seeds of some plants germinate immediately after shedding from the plants while in other plants they require a period of rest before germination. The later phenomena is called as dormancy. Give the reasons for seed dormancy and some methods to break it.

Non-living things also grow. Explain the statement with example.

What are the different types of cells present in the gastric gland?

The diagram shows a section through a villus. What is the function of structure X?

1. To absorb amino acids.
2. To carry blood.
3. To transport fats.
4. To transport glucose.

What does ‘S’ refer in a 70S & an 80S ribosome?

What effect will it have if all joints in the human arm become immobile?

1. When is a mineral element considered toxic in plant nutrition?
2. Why are the symptoms of toxicity difficult to identify?

1. Which phytohormone is also called a stress hormone? How does this hormone overcome stress conditions?
2. Name the phytohormone, which is widely used to kill the dicotyledonous weeds?

Which one of the following phylum is characterized by absence of true coelom?

1. Annelida.
2. Mollusca.
3. Echinodermata.
4. Nematoda.

State what will happen if plants are supplied with,

1. Low content of nitrogen.
2. Excess of sulphur.