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Biology · CELL THE UNIT OF LIFE
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Biology · CELL THE UNIT OF LIFE
In plant cells, the tonoplast plays a crucial physiological role by facilitating the transport of a number of ions and other materials. What is the direction and nature of this transport relative to concentration gradients?
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Given below are two statements:\n Statement I: The ribosomes of chloroplasts are 70S, which are smaller than the cytoplasmic 80S ribosomes of eukaryotic cells.\n Statement II: The inner membrane of the chloroplast is comparatively more permeable to solutes than its outer membrane. \nIn the light of the above statements, choose the most appropriate answer from the options given below:
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Consider the following statements regarding the formulation of cell theory: (A) Matthias Schleiden concluded that the presence of cell wall is a unique character of plant cells. (B) Theodore Schwann studied different types of animal cells and observed a thin outer layer known as plasma membrane. (C) Schleiden and Schwann together formulated the cell theory but could not explain how new cells were formed. Which of the above statements are correct?
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Gas vacuoles are specialized non-membrane bound structures providing buoyancy. In which group of organisms are they found?
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Based on his studies on plant tissues, who concluded that the presence of a cell wall is a unique character of plant cells?
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Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Mitochondria, chloroplasts, and peroxisomes are not considered parts of the endomembrane system. Reason (R): The functions of mitochondria, chloroplasts, and peroxisomes are not coordinated with the components consisting of ER, Golgi complex, lysosomes, and vacuoles. In the light of the above statements, choose the correct answer from the options given below:
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Consider the following statements regarding the eukaryotic cytoskeleton and motile appendages: (A) The cytoskeleton comprises microtubules, microfilaments, and intermediate filaments involved in mechanical support, motility, and cell shape maintenance. (B) Prokaryotic flagella possess a \( 9+2 \) axonemal microtubular arrangement identical to eukaryotic cilia. (C) Both cilium and flagellum emerge from a centriole-like structure known as the basal body. (D) Centrioles form the basal body of cilia and flagella, and spindle fibres that give rise to spindle apparatus during animal cell division. How many of the above statements are correct?
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Given below are two statements: Statement I: Mycoplasmas are the smallest known cells and are only 0.3 µm in length. Statement II: The largest isolated single cell is the egg of an ostrich. In the light of the above statements, choose the most appropriate answer from the options given below:
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Match List-I with List-II: List-I (Bacterial Shape) List-II (Morphological Form) A Bacillus I Spherical B Coccus II Comma-shaped C Vibrio III Rod-like D Spirillum IV Spiral Choose the correct answer from the options given below:
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Which of the following statements regarding the nuclear envelope, perinuclear space, and nucleolus in an interphase eukaryotic cell is fully accurate?
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Consider the structural polarity and dimensional characteristics of the Golgi apparatus. Which of the following statements accurately describes its architecture?
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Mesosomes in prokaryotes are formed by extensions of the plasma membrane. Which of the following functions is NOT carried out by mesosomes?
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Which structural and chemical feature correctly distinguishes the inner mitochondrial membrane and matrix from the outer mitochondrial membrane?
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Who among the following scientists first observed and described a live cell?
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Refer to the provided diagram depicting types of chromosomes based on the position of centromere (Figure 8.13). What is the correct sequence of chromosome types shown from left to right?
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Refer to the diagrammatic representation of the Fluid mosaic model of plasma membrane (Figure 8.4): Where are the hydrophobic tails of saturated hydrocarbons located in relation to the aqueous exterior?
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Consider the following statements regarding differences between plant and animal cells: (A) Plant cells possess cell walls, plastids, and a large central vacuole. (B) Animal cells have centrioles which are absent in almost all plant cells. (C) Centrosome is a membrane-bound organelle involved in photosynthesis. (D) Plant cells possess centrioles to assist in spindle formation. Choose the correct answer from the options given below:
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The given diagrammatic representation (Figure 8.10) shows the cross-section of a eukaryotic flagellum/cilium. Which statement correctly identifies the components and microtubular geometry of this axoneme?
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Match List-I with List-II: List-I List-II A Middle lamella I Mainly composed of calcium pectate B Algal cell wall II Cellulose, galactans, mannans and minerals like \( \text{CaCO}_3 \) C Primary cell wall III Capable of growth, diminishes as cell matures D Secondary cell wall IV Formed on the inner (towards membrane) side of the cell Choose the correct answer from the options given below:
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Which of the following cellular organelles are excluded from the endomembrane system, and on what conceptual basis is this exclusion justified?
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Refer to the diagram of an animal cell (Figure 8.3b): Which non-membrane bound organelle is visible in the animal cell that helps in cell division but is absent in almost all plant cells?
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Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Phospholipids in the plasma membrane are arranged with their hydrophobic tails facing towards the aqueous outer surface. Reason (R): The nonpolar tails of saturated hydrocarbons require constant contact with water molecules to stabilize the lipid bilayer. In the light of the above statements, choose the correct answer from the options given below:
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