PART - 1 - Unit III : CH - 9 Biomolecules — BIOLOGY STD 11 Science — Question

Ankit, a Xl class student was continuously listening to his sister and her friend's discussion about the growth of plant. They were discussing that plant growth involves three phenomena, i.e., differentiation, dedifferentiation and redifferention. Listening this Ankit interrupted them in between and asked her sister to elaborate the things in detail and the basic phenomenon behind it. As the topic was the part of the Ankit's syllabus also. Her sister explained him that the cells in plant undergo differentiation to attain a maturity in order to perform specific functions.

1. What is dedifferentiation? Name two tissues formed by this process phenomenon.
2. What is redifferentiation?
3. What value is learnt from the Ankit's character as an ideal biology student.

Differentiate between the following: Imbibition and diffusion

Mention the ploidy of the following:
i. Protonemal cell of a moss
ii. Primary endosperm nucleus in dicot
iii. Leaf cell of a moss
iv. Prothallus cell of a fern
v. Gemma cell in Marchantia
vi. Meristem cell of monocot
vii. Ovum of a liverwort
viii. Zygote of a fern

Sunday morning Abhishek and his friends emptied all the overhead tanks belonging to flat owners who were not residing in their apartments for the last few months. On their return, the owners complained about their empty tanks. Some elderly people even spoke against Abhishek and his friends. Abhishek humbly apologised for the inconvenience caused. He explained that water in the tanks had become stagnant and become a breeding ground for mosquitoes which will give rise to malaria. The people appreciated the boys.

1. What values are reflected by Abhishek in the above case?
2. What is the causal agent of malaria and how does it reach human body?
3. How many phases the causal organism undergoes in its life cycle?
4. As an individual what can you do to avoid malaria in your neighbourhood?

The number and kinds of organism is not constant. How do you explain this statement?

Apart from chlorophyll, algae have several other pigments in their chloroplast. What pigments are found in blue-green, red and brown algae that are responsible for their characteristic colours?

Describe the basis on which Gap-1 phase, Synthetic phase and Gap-2 phase of cell cycle are named.

How are ascospores and conidia, both produced by Ascomycetes, different from each other?

Name the hormones, their source glands and their mode of functioning to achieve calcium hormeostasis in the human body.