BackAnatomy & Physiology: Cell Structure and Function
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Terms in this set (25)
A cell is the basic structural and functional unit of all living organisms, capable of independent life and performing essential life processes.
The fluid mosaic model describes the cell membrane as a flexible layer made of a phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates, allowing fluidity and selective permeability.
Phospholipids form the bilayer structure of the membrane, with hydrophilic heads facing outward and hydrophobic tails inward, creating a semi-permeable barrier.
Membrane proteins act as channels, carriers, receptors, enzymes, and structural anchors, facilitating transport and communication across the membrane.
Cholesterol stabilizes membrane fluidity by preventing phospholipids from packing too tightly or becoming too fluid.
Carbohydrates attached to proteins or lipids form glycoproteins and glycolipids, which are involved in cell recognition and signaling.
Key organelles include the nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, ribosomes, and cytoskeleton.
The nucleus stores genetic material (DNA) and controls cellular activities by regulating gene expression.
Mitochondria generate ATP through cellular respiration, providing energy for the cell.
The RER synthesizes and processes proteins destined for membranes or secretion, characterized by ribosomes on its surface.
The SER synthesizes lipids, metabolizes carbohydrates, and detoxifies drugs and poisons.
The Golgi apparatus modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.
Lysosomes contain digestive enzymes that break down waste materials and cellular debris.
Ribosomes are the sites of protein synthesis, translating mRNA into polypeptide chains.
The cytoskeleton is a network of protein filaments that maintain cell shape, enable movement, and organize organelles.
Interphase includes G1 (cell growth), S (DNA replication), and G2 (preparation for mitosis).
During G1, the cell grows and synthesizes proteins and organelles needed for DNA replication.
S phase is when the cell duplicates its DNA, resulting in two identical sets of chromosomes.
G2 phase involves further growth and synthesis of proteins required for mitosis.
The stages are prophase, metaphase, anaphase, and telophase.
In prophase, chromatin condenses into chromosomes, the nuclear envelope breaks down, and spindle fibers form.
During metaphase, chromosomes align at the cell's equatorial plate, attached to spindle fibers.
Anaphase involves separation of sister chromatids, which move toward opposite poles of the cell.
In telophase, chromosomes decondense, nuclear envelopes reform, and the cell prepares to divide.
Mitosis enables growth, tissue repair, and replacement of damaged or dead cells.