Cell Structure/Mitosis phases Flashcards
(54 cards)
Fluid bi-layer of lipid molecules with protein molecules dispersed in it.
The lipid bilayer is basically comprised of phospholipids with a polar “head” that is charged and hydrophilic (likes water) and an uncharged, nonpolar “tail” that is hydrophobic (hates water)
Plasma membrane
minute fingerlike extensions of the plasma membrane.
Increase the surface area of the plasma membrane.
Found on the surface of absorptive cells such as intestines and kidney tubule cells
Microvilli
a series of integral protein molecules in the plasma membranes of adjacent cells fused together.
Form an impermeable junction that encircles the cell.
Help prevent molecules from passing through the extracellular space between adjacent cells
Tight Junctions
are anchoring junctions.
Prevents adjoining cells from separating
Desmosomes
a communicating junction allowing chemical substances to pass between adjacent cells
Gap junctions
the cellular material between the plasma membrane and the nucleus. Most cellular activities occurs here.
Cytoplasm
Three major elements comprise the cytoplasm
cytosol, cytoplasmic organelles, inclusions
the fluid in which the other cytoplasmic elements are suspended
cytosol
the metabolic machinery of the cell.
cytoplasmic organelles
chemical substances that may or may not be present, depending on the cell type.
Ex. stored nutrients.
inclusions
specialized cellular compartments, each performing its own job to maintain the life of the cell
Cytoplasmic Organelles
threadlike or sausage-shaped membranous organelle.
The “powerhouse” of the cell, providing the cell with most of its ATP supply
Mitochondria
small, dark-staining granules composed of proteins and a variety of RNA called ribosomal RNA. Sites of protein synthesis
Ribosomes
an extensive system of interconnected tubes and parallel membranes enclosing fluid-filled cavities (cisternae).
It coils and twists through the cytosol.
Endoplasmic Reticulum (ER)
Two varieties of Endoplasmic Reticulum (ER)
Rough endoplasmic reticulum (Rough ER)
Smooth endoplasmic reticulum (smooth ER)
External surface contains ribosomes.
ocated in most secretory cells, antibody-producing plasma cells, and liver cells producing most blood proteins.
It’s also the cell’s “membrane factory”.
Integral proteins and phospholipids that form part of all cellular membranes are manufactured here
Rough endoplasmic reticulum
A continuation of the rough ER consisting of tubules arranged in a looping network.
Its enzymes catalyze reactions involved in the following processes:
a. Lipid metabolism, cholesterol synthesis, and synthesis of lipid components of lipidproteins.
b. Synthesis of steroid-based hormones such as sex hormones.
c. Absorption, synthesis, and transport of fats.
d. Detoxification of drugs, certain pesticides, and carcinogens.
e. Breakdown of stored glycogen to from free glucose.
Smooth endoplasmic reticulum
Consists of stacked and flattened membranous sacs associated with swarms of tiny membranous vesicles.
Principal “traffic director” for cellular proteins.
Major function is to modify, concentrate, and package the proteins and lipids made at the rough ER
Golgi apparatus
contain digestive enzymes. Abundant in phagocytes (cells that dispose of invading bacteria and cell debris).
Function as cells’ “demolition crew” by:
Digesting particles taken in by endocytosis.
Degrading worn-out or nonfunctional organelles.
Performing metabolic functions.
Breaking down non-useful tissues.
Break down bone to release calcium ions into the blood.
Lysosomes, if damaged, will self-digest itself by a process called autolysis
Lysosomes
membranous sacs containing a variety of powerful enzymes
Peroxisomes
Hollow tubes made of spherical protein subunits called tubulins.
Determines the overall shape of the cell along with the distribution of organelles.
Mitochondria, lysosomes, and secretory granules attached to microtubules.
Microtubules
the thinnest elements are strands of the protein actin.
Each cell has a unique arrangement. Attached to the cytoplasmic side of the cell’s plasma membrane which gives strength to the cell’s surface.
Involved in cell motility or changes in cell shape.
Funtions: Actin with myosin help contract muscles and forms the cleavage furrow that pinches a cell in two during cell division.
Also responsible for the crawling movement of amoeboid motion, and for the membrane changes that accompany endocytosis and exocytosis
Microfilaments
tough, insoluble protein fibers that have a diameter between those of microfilaments and microtubules.
Most stable and permanent element of the cytoskeleton.
High tensile strength and act as internal guy wires to resist pulling forces exerted on the cell
Intermediate filaments
a region near the nucleus where microtubules are anchored.
Act as a microtubule organizing center and has a granular-looking matrix which contains centrioles
Centrosome
