Latest questions in this category.
The nuclear envelope forms a barrier between the nucleus and cytoplasm. Its outer membrane is continuous with ER and may bear ribosomes. Fusion of its two membranes forms nuclear pores through which RNA and proteins move in both directions.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Endomembrane System - ER Golgi Lysosome Vacuole
ER contributes to intracellular transport and to the synthesis of proteins, lipoproteins and glycogen. Rough ER is associated with protein synthesis and secretion, while smooth ER synthesises lipids and lipid-like steroidal hormones.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Endomembrane System - ER Golgi Lysosome Vacuole
Lysosomes are membrane-bound vesicles containing hydrolytic enzymes that are optimally active at acidic pH. Mitochondria are double-membrane organelles whose inner membrane forms cristae and whose aerobic respiratory activity generates ATP.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Endomembrane System - ER Golgi Lysosome Vacuole
Neutral solutes may diffuse down their concentration gradient without energy. Polar molecules require carrier proteins to cross the non-polar bilayer. Movement against a gradient is active transport and requires energy supplied through ATP.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Endomembrane System - ER Golgi Lysosome Vacuole
Secretory proteins are synthesised on ribosomes attached to RER. Materials from the ER reach the cis or forming face of the Golgi, move through its cisternae and are released from the trans or maturing face.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Endomembrane System - ER Golgi Lysosome Vacuole
The Golgi apparatus packages materials for intracellular delivery or secretion. Lysosomes are also formed through Golgi packaging. ATP production occurs in mitochondria, while lipid and steroid synthesis occurs mainly in the SER.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Endomembrane System - ER Golgi Lysosome Vacuole
RER is abundant in cells involved in protein synthesis and secretion. The Golgi apparatus modifies and packages proteins, while large and numerous nucleoli occur in cells actively carrying out protein synthesis because the nucleolus synthesises ribosomal RNA.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Endomembrane System - ER Golgi Lysosome Vacuole
Lysosomes are membrane-bound vesicular structures formed through packaging by the Golgi apparatus. They contain hydrolytic enzymes capable of digesting several types of biological macromolecules.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Endomembrane System - ER Golgi Lysosome Vacuole
Golgi cisternae are flat, disc-shaped sacs approximately 0.5–1.0 µm in diameter. A variable number of cisternae are stacked parallel to one another and arranged near the nucleus.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Endomembrane System - ER Golgi Lysosome Vacuole
The Golgi apparatus has a distinct convex cis or forming face and a concave trans or maturing face. The two faces are different but interconnected.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Endomembrane System - ER Golgi Lysosome Vacuole
The Golgi apparatus modifies materials received from the endoplasmic reticulum and is an important site for the formation of glycoproteins and glycolipids.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Endomembrane System - ER Golgi Lysosome Vacuole
Plant cells possess a cell wall, plastids and a large central vacuole, which are absent from animal cells. Animal cells possess centrioles, which are absent from almost all plant cells.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Endomembrane System - ER Golgi Lysosome Vacuole
