MODEL PAPER 1 BIOLOGY - MODEL PAPER 1

Loud snoring and labored breathing are symptoms of:

The following substances are the excretory products in animals. Choose the least toxic form among them.

In mosses, the sex organs arise from:

A farmer grows cucumber plants in his field. He wants to increase the number of female flowers in them. Which plant hormones can be applied to achieve this ?

Platelets are formed from the _____________.

Why is the colour of a leaf kept in the dark frequently yellow, or pale green? Which pigment do you think is more stable?

Eichornia crassipes is called as an exotic species while Rauvolfia serpentine is an endemic species in India. What do these terms exotic and endemic refer to?

Mention any four activities regulated by the estrogen hormone.

Draw a well labelled diagram of both ventral and dorsal views of the brain of the frog.

Differentiate between right ventricle and left ventricle.

How do you call the conduction of impulse along a myelinated nerve fibre?

What is the significance of the time gap in the passage of action potential from the sinoatrial node to the ventricle?

Mention and explain the special properties of muscle.

Name one synthetic auxin that can be used as a herbicide. Give one more application of the same.

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)

Give the biochemical composition of plasma membrane. How are lipid molecules arranged in the membrane?

Is there a species or region specific type of plastids? How does one distinguish one from the other?

Describe briefly the main steps on glycolysis from triose phosphate onwards. Highlight the reactions which release energy.

Enumerate the assumptions that we undertake in making the respiratory balance sheet. Are these assumptions valid for a living system? Compare fermentation and aerobic respiration in this context.

A well-known biologist stated that the life history of an organism can be summed up as gametic fusion, equational division and reductional division. Comment on it.

Assertion (A): Abdominal muscle is related with respiration in animals.
Reason (R): Relaxation of abdominal muscles draws in air.

Assertion (A): Enzymes of glycolysis are constitutive enzymes.
Reason (R): They are present over mitochondrial cristae.

Assertion (A): Hippocrates is known as father of Biology.
Reason (R): Hippocrates gave binomial classification of organisms.