Cell Structure and Cell Types

Early biologists saw cells as simple membranous sacs, while modern biologists know that cells are complex structures with various organelles and intricate arrangements of fibers.

The cell membrane separates the extracellular material from the intracellular material, maintains the integrity of the cell, and controls the passage of materials into and out of the cell. It is composed of a double layer of phospholipid molecules with embedded proteins.

The nucleus is the control center of the cell, determining how the cell will function and its basic structure. It is formed by a nuclear membrane around a fluid nucleoplasm and contains chromatin with DNA and a nucleolus with RNA.

<p>The cytoplasm is the gel-like fluid inside the cell, serving as the medium for chemical reactions and containing organelles and fibers.</p> Signup and view all the answers

<p>Intracellular materials are those found inside the cell, while extracellular materials are those found outside the cell.</p> Signup and view all the answers

<p>Proteins in the cell membrane provide structural support, form channels for passage of materials, act as receptor sites, function as carrier molecules, and provide identification markers.</p> Signup and view all the answers

<p>The nucleolus is a dense region of RNA in the nucleus and is the site of ribosome formation.</p> Signup and view all the answers

<p>Organelles are miniscule but distinct structures found within the cytoplasm of a cell, performing specific functions necessary for cellular survival.</p> Signup and view all the answers

<p>A 'generalized cell' is a concept that includes features from all cell types, introduced for descriptive purposes to illustrate the common structures found in all cells.</p> Signup and view all the answers

<p>The cell membrane serves as the boundary of the cell, controlling the passage of materials into and out of the cell and maintaining the integrity of the cell.</p> Signup and view all the answers