Case study (4 Marks)

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Question 14 Marks

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)

Answer

i. An androecium is the male part of the flower which is composed of a long filament and an anther attached to its tip.
ii. Sterile stamen is called staminode.
iii. Yes, salvia and mustard show variation in the length of filaments within a flower.

OR

a. The main axis continues to grow.
b. The flowers are borne laterally in an acropetal succession.

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Question 24 Marks

Sarcodines are unicellular/jelly-like protozoa found in fresh or sea water and in moist soil. Their body lacks a periplast. Therefore, they may be naked or covered by a calcareous shell. They usually lack flagella and have temporary protoplasmic outgrowths called pseudopodia. These pseudopodia or false feet help in movement and capturing prey. They include free-living forms such as Amoeba or parasitic forms such as Entamoeba. Zoo flagellates ciliates and I sporozoans are other groups of protozoan protists. They are all unicellular and heterotrophic. They may be holozoic, saprobic or parasitic.

i. Write two lines about flagellated protozoans and also mention some flagellated protozoans. (1)
ii. Observe the given protozoan classification and mention what is the basis of protozoan classification. (1)
iii. Mention some locomotory organs of protozoa. (2)

OR

Which protozoan group has two nuclei, macronucleus, and micronucleus? Mention characteristics of it. (2)

Answer

i. Flagellated protozoans are either free-living or parasitic protozoans that have flagella. Sleeping sickness is caused by parasitic
versions of the parasite.Trypanosoma is a good example.
ii. • Locomotion
• Protozoan are eukaryotic having different shapes and sizes. Some are ciliated flagellated or both may be absent.
iii. a. Cilia
b. Flagella
c. Pseudopodia

OR

Ciliata has two nuclei, macronucleus, and micronucleus.
Ciliates are characterized as organisms propelled by rows of cilia and possessing two types of nuclei. They are a large macronucleus involved in vegetative functions of the organism, and a small micronucleus involved in sexuality.

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BIOLOGY Case study (4 Marks)

Case study (4 Marks)

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