CBSE Class 11 Biology Important Questions

1. What are the main characteristics that define living organisms, and how do they differentiate from non-living things?

Answer: Living organisms exhibit several key characteristics, including:

• Metabolism: All living things undergo chemical processes that provide energy for growth and maintenance.

• Growth and Development: Organisms grow and develop according to specific genetic instructions.

• Reproduction: Living beings have the ability to reproduce, either sexually or asexually, to produce offspring.

• Response to Stimuli: They respond to environmental changes through various mechanisms, ensuring survival.

• Homeostasis: Living organisms maintain a stable internal environment despite external changes. These characteristics distinguish living organisms from non-living things, which do not exhibit these complex biological functions.

2. Explain the five major kingdoms of life and provide examples of organisms in each kingdom.

Answer: The five major kingdoms of life are:

• Monera: This kingdom includes unicellular organisms without a nucleus, such as bacteria and cyanobacteria.

• Protista: Comprising mostly unicellular eukaryotic organisms, examples include amoeba and paramecium.

• Fungi: This kingdom consists of multicellular and unicellular organisms that absorb nutrients from organic matter, such as mushrooms and yeast.

• Plantae: Comprising multicellular organisms that perform photosynthesis, examples include flowering plants and ferns.

• Animalia: This kingdom includes multicellular organisms that are heterotrophic, such as mammals, birds, and insects.

3. Describe the main differences between monocots and dicots in the Plant Kingdom.

Answer:

Monocots and dicots are two major groups of flowering plants with distinct features:

• Monocots: They have one cotyledon, parallel leaf venation, scattered vascular bundles, and flower parts typically in multiples of three. Examples include grasses and lilies.

• Dicots: They possess two cotyledons, net-like leaf venation, vascular bundles arranged in a circle, and flower parts typically in multiples of four or five. Examples include roses and sunflowers.

4. What is the morphology of flowering plants, and what are the key parts of a flower?

Answer: The morphology of flowering plants refers to their structural features. Key parts of a flower include:

• Sepals: These protect the flower bud before it opens.

• Petals: Often colourful, petals attract pollinators.

• Stamens: The male reproductive part, consisting of the anther (produces pollen) and filament.

• Carpels: The female reproductive part, made up of the stigma (receives pollen), style, and ovary (contains ovules). These parts work together for reproduction and pollination.

5. Discuss the process of photosynthesis in higher plants, including the light-dependent and light-independent reactions.

Answer: Photosynthesis occurs in two main stages:

• Light-dependent Reactions: These take place in the thylakoid membranes of chloroplasts, where sunlight is absorbed by chlorophyll, leading to the splitting of water molecules (photolysis) and the production of ATP and NADPH.

• Light-independent Reactions (Calvin Cycle): Occurring in the stroma of chloroplasts, ATP and NADPH from the light-dependent reactions are used to convert carbon dioxide into glucose. This process produces energy-rich compounds that sustain plant growth.

6. What are the main components of the cell and their functions?

Answer: Cells have several key components, including:

• Nucleus: Contains genetic material (DNA) and controls cellular activities.

• Mitochondria: Known as the powerhouse of the cell, they produce ATP through respiration.

• Ribosomes: Sites of protein synthesis, translating RNA into proteins.

• Cell Membrane: A selective barrier that regulates the entry and exit of substances.

• Endoplasmic Reticulum (ER): Rough ER is involved in protein synthesis, while smooth ER is involved in lipid synthesis and detoxification.

7. Explain the stages of the cell cycle and the significance of cell division.

Answer: The cell cycle consists of several stages:

• Interphase: The cell grows and prepares for division, with phases including G1 (growth), S (DNA synthesis), and G2 (preparation for mitosis).

• Mitotic Phase: Includes mitosis (division of the nucleus) and cytokinesis (division of the cytoplasm). Cell division is significant for growth, tissue repair, and reproduction. It ensures that each daughter cell receives an identical set of chromosomes, maintaining genetic continuity.

8. What are the mechanisms of breathing and gas exchange in plants and animals?

Plants: Breathing occurs through small openings called stomata, where carbon dioxide enters and oxygen exits. Gas exchange in plants mainly happens during photosynthesis and respiration.

Animals: Breathing involves inhalation and exhalation, facilitated by respiratory organs like lungs or gills. In animals, oxygen is absorbed into the blood, and carbon dioxide is expelled, often through structures like alveoli in the lungs or gill filaments in fish.

9. Discuss the role of body fluids in circulation and the functions of the circulatory system in humans.

Answer: Body fluids, primarily blood, play a crucial role in circulation. The circulatory system consists of:

• Heart: Pumps blood throughout the body.

• Blood Vessels: Arteries carry oxygenated blood away from the heart, while veins return deoxygenated blood.

• Functions: The circulatory system transports oxygen, nutrients, hormones, and waste products. It also helps regulate temperature and pH levels, ensuring homeostasis.

10. Describe the neural control and coordination in animals, focusing on the structure and function of neurons.

Answer: Neural control and coordination involve the nervous system, which consists of the brain, spinal cord, and nerves. Neurons are the fundamental units of the nervous system and consist of:

• Dendrites: Receive signals from other neurons.

• Cell Body: Contains the nucleus and integrates incoming signals.

• Axon: Transmits electrical impulses away from the cell body to other neurons or muscles. The coordinated activity of neurons enables quick responses to stimuli, maintaining homeostasis and facilitating movement and behaviour in animals.

Here, you will find 10 overall important questions for Class 11 Biology. For a more detailed understanding and chapter-wise important questions, please click on the link above to access the complete resource. This will help you understand key concepts and prepare effectively for your exams.

How do Biology Important Questions Class 11 Help you with Exams?

• Biology important questions help students focus on key topics that are likely to appear in exams. This targeted approach makes studying more effective.

• Practicing these questions boosts confidence as students become familiar with the types of questions they may encounter. It also improves their understanding of core concepts.

• Reviewing important questions allows for quick revisions, ensuring that students can easily recall essential information before exams.

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Vedantu's Class 11 Biology Important Questions are a valuable resource for students preparing for their exams. By focusing on key topics and concepts, these questions help understanding and build confidence. Practicing these important questions not only aids in effective revision but also enhances problem-solving skills. Students are encouraged to make the most of this resource to achieve better results and deepen their knowledge of biology.

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