Cells Flashcards
(87 cards)
Cellular Projections
Not found in all cells, used for movement
Cilia moves materials across the cell surface
Flagellum propels the cell
Phospholipid Structure
A phospholipid molecule consists of a polar phosphate “head”, which is hydrophilic and non-polar lipid “tail”, which is hydrophobic. Unsaturated fatty acids result in kinks in the hydrophobic tails.
Phospholipid Bilayer
The phospholipid bilayer consists of two adjacent sheets of phospholipids, arranged tail to tail. The hydrophobic tails associate with one another, forming the interior of the membrane. The polar heads contact the fluid inside and outside of the cell.
Cell Membrane
The cell membrane of the cell is a phospholipid bilayer containing many different molecular components, including proteins and cholesterol, some with carbohydrates groups attached.
Simple diffusion across the call (plasma) membrane
The structure of the lipid bilayer allows only small non-polar substances such as oxygen and carbon dioxide to pass through the cell membrane, down their concentration gradient, by simple diffusion.
Facilitated Diffusion
Facilitated Diffusion of substances crossing the cell (plasma) membrane takes place with the help of proteins such as channel proteins and carriers proteins. Channel proteins are less selective than carrier proteins, and usually mildly discriminate between their cargo based on size and charge. Carrier proteins are more selective often only allowing one particular type of molecule to cross.
Osmosis
Osmosis is the diffusion of water through a semipermeable membrane down its concentration gradient. If a membrane is permeable to water, though not to a solute, water will equalize its own concentration by diffusion to the side of lower water concentration (and thus the side of higher solute concentration).
Hypertonic
solute concentration higher than another solution
Isotonic
solution has a solute concentration equal to another solution
Hypotonic
a solute concentration lower than another solution
sodium potassium pump
It is found in many cell (plasma) membranes. Powered by ATP, the pomp moves sodium and potassium ions in opposite directions, each against its concentration gradient. In a single cycle of the pump, 3 sodium ions are extruded from and 2 potassium ions are imported into the cell.
3 sodium (NA+): 2 potassium (K+)
endocytosis
Is a form of active transport in which a cell envelopes extracellular materials using its cell membrane.
Phagocytosis
which is relatively nonselective, the cell takes in a large particle
pinocytosis
the cell takes in small particles in fluid.
Receptor- mediated endocytosis
is quite selective, when external receptors bind a specific ligand, the cell responds by endocytosing the ligand
Exocytosis
Endocytosis in reverse. Material destined for export is packaged into a vesicle inside the cell. The membrane of the vesicle fuses with the cell membrane, and the contents are released into the extracellular space.
Smooth ER
synthesizes phospholipids, steroid hormones, regulates the concentration of cellular CA++, metabolizes some carbohydrates, and breaks down certain toxins
Rough ER
studded with numerous ribosomes, which are sites for protein synthesis
Golgi Apparatus
Manipulates products from the rough ER, and also produces new organelles called lysosomes. Proteins and other products of the ER are sent to the Golgi apparatus, which organizes, modifies, packages, and tags them. Some of these products are transported to other areas of the cell and some are exported from the cell through exocytosis.
Mitochondrion
They are the energy- conversion factories of the cell. A mitochondrion is composed of 2 separate lipid bilayer membranes. Along the inner membrane are various molecules that work together to produce ATP, the cell’s major energy currency.
Peroxisome
membrane bound organelles that contain an abundance of enzymes for detoxing harmful substances and lipid metabolism.
3 components of the cytoskeleton
consists of microtubules, microfilaments, and intermediate filaments. The cytoskeleton plays an important role in maintaining cell shape and structure, promoting cellular movement, and aiding cell division.
Nucleus
the control center of the cell, the nucleus of living cells contains the genetic material that determines the entire structure and function of that cell
multinucleate muscle cell
Unlike cardiac muscle cells and smooth muscle cell, which have single nucleus, a skeletal muscle cell contains many nuclei, and is referred to as “multinucleated”. These muscle cells are long and fibrous (often referred to as muscle fibers). During development, many smaller cells fuse to form a mature muscle fiber. The nuclei of the fused cells are conserved in the mature cell, thus imparting a multinucleated characteristic to mature muscle cells.
