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BIOLOGY Case study (4 Marks)

MODEL PAPER 1 · Gujarat Board (GSEB) STD 11 Science (GSEB - English Medium). 2 questions.

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Case study (4 Marks)

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2 questions · self-marked practice — reveal the answer and mark yourself.

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.
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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)
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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.<br>b. The flowers are borne laterally in an acropetal succession.
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Question 24 Marks
Linnaeus gave two kingdom classification/which consists of kingdom Plantae and kingdom Animalia. This classification was based on the mode of nutrition/ reproduction/ presence or absence of cell wall. However, this system had many drawbacks like there was no distinction between eukaryotes and prokaryotes. Then, came the three-kingdom classification in which single-celled bacteria and protozoans were kept in the kingdom Protista.This system also failed to classify all living organisms into appropriate categories. Finally a five Kingdom classification was proposed by dividing all the organisms into five kingdom and it will be accepted as modern system of classification.
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i. We know that Haeckel proposed the term Protista for unicellular organisms. Observe the given flowchart and mention what are advantages does the five-kingdom classification have over the two-kingdom classification?
ii. All eukaryotic unicellular organisms belong to which kingdom? Also, mention its two characteristics.
iii. What is heterotropic? Is Euglena heterotropic?
OR
iii. Who proposed the five-kingdom classification? And which criteria were used to classify organism in the 5- kingdom system?
Answer
i. The advantages of five-kingdom classification over two-kingdom classification are as follows:
• It is based on cell structure
• It is based on the body structure
• Nutrition
• Way of living
• Phylogenetic relationship
ii. Protista
Characteristic of protists:
• Most of them live in water while some inhabit moist places.
• They have a membrane-bound nucleus and other cellular organelles
iii. Heterotrophs are those organisms that cannot prepare their own food and depend on other organisms (plants and animals) for food.
Yes, Euglena is hetrotropic and also possess chorophyll like plants to synthesize 1 their food.
OR
iii. R. H. Whittaker proposed the five-kingdom classification.
R.H. Whittaker's primary classification criteria include cell structure, body organization, mode of nutrition, reproduction, and phylogenetic relationships.
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