cells Flashcards
all cells have three main regions or parts
a plasma membrane, a nucleus (nu′kle-us), and the cytoplasm (si′to-plazm″).
how the cell is structured
The nucleus is usually located near the center of the cell. It is surrounded by the semifluid cytoplasm, which in turn is enclosed by the plasma membrane, which forms the outer cell boundary.
What is the phospholipid bilayer, and how does it contribute to the plasma membrane’s function?
This is made up of two layers. The hydrophilic (water-loving) heads faceing outward, and the hydrophobic (water-fearing) tails face inward. This creats a barrier seperating inner from outer cell, only allowing passing for small,non polar,molecules
What are integral proteins, and what are their main functions in the plasma membrane?
types of proteins are found in the plasma membrane:These span the membrane and help transport molecules across the membrane.act as receptors to tell the cell
What is the phospholipid bilayer, and how does it contribute to the plasma membrane’s function?
The phospholipid bilayer is made of two layers of phospholipids. The hydrophilic (water-loving) heads face outward, and the hydrophobic (water-fearing) tails face inward. This structure creates a barrier that separates the inside of the cell from the outside, allowing selective passage of small, non-polar molecules.
What types of proteins are found in the plasma membrane, and what are their functions?
Cadherins These are located on the surface of the membrane and play roles in cell signaling, shape, and maintaining cell structure.
What role does cholesterol play in the plasma membrane?
so basicaly it makes the plasma membrane not to fluid or to rigid and that its flexible
Carbohydrates in the plasma
Carbohydrates are attached to proteins (called glycoproteins) and lipids (called glycolipids) on the outside of the plasma membrane. These carbohydrates help the cell:
Recognize other cells (for example, in the immune system).
Communicate with other cells.
Stick to other cells (important for tissue formation).
Tight Junctions:plasma membrane
Function: Tight junctions seal adjacent cells together, preventing substances from leaking between them.
Example: They are found in tissues like the lining of the intestines, where they prevent digestive enzymes and harmful substances from leaking into surrounding tissues.
Adherens Junctions
Function: Adherens junctions help anchor cells together, using protein filaments (like actin) to link the cytoskeleton of cells next to them.
Example: Found in tissues that experience mechanical stress, like the heart and skin, to help cells resist stretching.
Desmosomes
bring cells close together, providing strength and helping them resist being pulled apart under stress or tension. They act like strong anchors, ensuring the cells stay connected, even when the tissue stretches or experiences mechanical force.
Gap Junctions:
Function: Gap junctions allow for direct communication between adjacent cells by forming channels that let small molecules (like ions) pass through.
Example: Found in tissues like the heart and smooth muscles, where coordinated cell activity (like muscle contraction) is needed.
