Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

Scientists are attempting to determine the organisation of a cell membrane rather than merely observe the external outli

Detailed membrane structure became accessible with electron microscopy, while chemical and biochemical studies—especially of erythrocyte membranes—revealed lipids, proteins, cholesterol and carbohydrates. Together, these findings supported models of bilayer organisation and membrane proteins.

Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

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Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

A bacterium possesses an outer loose sheath, a rigid layer that maintains shape and an innermost selectively permeable m

The bacterial envelope consists of the outermost glycocalyx, followed by the cell wall and then the plasma membrane. Although the layers perform distinct functions, they operate together as a protective unit.

Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

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Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

Consider the following developments in cell biology: P. Robert Brown described the nucleus. Q. Camillo Golgi observed de

Robert Brown described the nucleus in 1831, Camillo Golgi observed the Golgi structures in 1898, George Palade observed ribosomes in 1953, and Singer and Nicolson proposed the fluid mosaic model in 1972.

Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

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Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

Consider the following relationships within the axoneme of a eukaryotic cilium: I. The two central microtubules are conn

The central pair is connected by bridges and enclosed by a central sheath. Nine radial spokes extend towards the peripheral doublets, and the peripheral doublets are also interconnected by linkers. These relationships accompany the 9+2 axonemal arrangement.

Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

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Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

Two cell-wall samples are chemically analysed: Sample P contains cellulose, galactans, mannans and calcium carbonate. Sa

Algal walls may contain cellulose, galactans, mannans and minerals such as calcium carbonate. In other plants, the wall is composed of cellulose, hemicellulose, pectins and proteins.

Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

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Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

Membranes isolated from two cell types contain phospholipids, cholesterol, proteins and carbohydrates. However, one memb

Cell membranes mainly contain lipids and proteins, and also possess cholesterol and carbohydrates. Different cell types may contain these basic components in different proportions, so their protein-to-lipid ratios need not be identical.

Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

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Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

A substance blocks every nuclear pore without damaging the nuclear envelope itself. Which effect would follow most direc

Nuclear pores are passages formed where the two nuclear-envelope membranes fuse. RNA and protein molecules move through them in both directions between the nucleus and cytoplasm, so blocking the pores would directly obstruct this exchange.

Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

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Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

A change makes the lipid bilayer of a cell membrane much less fluid. Which group of processes is most likely to be affec

Membrane fluidity results from lateral movement of proteins within the quasi-fluid lipid bilayer. This property is important in cell growth, formation of intercellular junctions, secretion, endocytosis and cell division.

Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

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Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

What is a major structural function of the bacterial cell wall?

The bacterial cell wall determines the shape of the cell and provides strong structural support. This support protects the bacterium from bursting or collapsing.

Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

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Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

Which scientist–contribution combination is correctly matched?

Robert Brown described the nucleus as a cell organelle in 1831. Flemming later used the term chromatin for the nuclear material that stained with basic dyes.

Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

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Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

Which combination may occur in the cell wall of algae?

Algal cell walls may contain cellulose, galactans, mannans and minerals such as calcium carbonate. In other plants, the wall contains cellulose, hemicellulose, pectins and proteins.

Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

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Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

What is the principal role of plasmodesmata in plant tissues?

Plasmodesmata traverse the cell walls and middle lamellae of neighbouring plant cells. They establish connections between the cytoplasm of adjacent cells.

Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Eukaryotic Cell - Cell Wall and Cell Membrane - Fluid Mosaic Model

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