PART - 1 - Unit I : CH - 2 Biological Classification — BIOLOGY STD 11 Science — Question

Write four differences between A-band and I-band and draw a labelled diagram illustrating a transverse section of muscle showing muscle bundle and muscle fibres.

The androecium is composed of stamens. Each stamen that represents the male reproductive organ consists of a stalk or a filament and an anther. Each anther is usually bilobed and each lobe has two chambers, the pollen-sacs. Stamens of flowers may be united with other members such as petals or among themselves. The stamens may be epipetalous or epiphyllous. A flower is a modified shoot wherein the shoot apical meristem changes to floral meristem. Internodes do not elongate and the axis gets condensed. The apex produces different kinds of floral appendages laterally at successive nodes instead of leaves. The arrangement of flowers on the floral axis is termed an inflorescence.


i. Observe the figure and mention what is androecium composed of. (1)
ii. The pollen grains are produced in pollen-sacs. What is a sterile stamen is called? (1)
iii. Is salvia and mustard show variation in the length of filaments within a flower? (2)

OR

Mention statement justifies that the given figure is racemose inflorescence. (2)

Briefly describe the structure of the Brain.

Polysaccharides or the macro molecules consisting of long chains of sugar. Only carbohydrates they are not sweet and are insoluble in water. The two ends of the polysaccharide chain are called reducing and non-reducing ends. Based upon their monomeric units these are homo polysaccharides or heteropolysaccharides. Depending upon their location polysaccharides play multiple functions in living world few examples of polysaccharides include Cellulose, chitin, inulin etc.

(1) All the listed polysaccharides are homopolymers except
(a) Starch (b) glycogen (c) Chitin (d) Cellulose

(2) Inulin is a polymer of
(a) glucose (b) fructose (c) glucose and sucrose (d) fructose and galactans

(3) Murein is a heteropolysaccharide like
(a) araban (b) xylan (c) hyaluronic acid (d) agar

(4) A polysaccharide found in the exoskeleton of crabs is
(a) Cellulose (b) pectin (c) murine (d) chitin

(5) The right end of the polysaccharide chain is called
(a) reducing end (b) non-reducing end (c) right end (d) none of these

Write short notes on the function of the following hormone :
Insulin and Glucagon

Briefly describe any four valves found in the human heart. Make labelled diagram of a cross section of a human heart.

As what is Equisetum commonly known? Write any four differences between Bryophytes and Pteridophytes.

Differentiate between
Respiration and Combustion

Draw a standard ECG and explain the different segments in it.