Biomolecules — BIOLOGY STD 11 Science — Question

Give one antagonistic functions of each of the following hormone pairs.

1. Gibberellins- Abscisic acid
2. Cytokinin- Ethylene
3. Ethylene- Auxin

Neurospora- an ascomycetes fungus has been used as a biological tool to understand the mechanism of plant genetics much in the same way as Drosophila has been used to study animal genetics. What makes Neurospora so important as a genetic tool?

Write short notes on:

1. Erythrocytes.
2. Leucocytes.
3. Structure of Heart.

A rubber band stretches and reverts back to its original position. Bubble gum stretches, but it would not return to its original position.
Is there any difference between the two processes? Discuss it with respect to plant growth (Hint: Elasticity (reversible) Plasticity (irreversible))

Write the types of following structures in mammals.
1. Kidney.
2. Fertilisation.
3. RBCs.
4. Brain.
5. Paternal care.
6. Sexual dimorphism.

"All vertebrates are chordates but all chordates are not vertebrates". Justify the statement.

Which of the following will release more energy on oxidation? Arrange 1 them in ascending order.

1. 1gm of fat.
2. 1gm of protein.
3. 1gm of glucose.
4. 0.5g of protein + 0.5g glucose.

Explain the difference between ultrafiltration and selective reabsorption.

Mention any four activities regulated by the estrogen hormone.

OR

List any four effects produced by estrogen.

Write the functions in brief in Column B, appropriate to the structures given in Column A.

1. Nictitating membrane __________. 
2. Tympanum __________.
3. Copulatory pad __________.