cell membrane
regulates the passage of substances into and out of the cell
What molecules make up the cell membrane?
lipids and proteins
types of lipids
phospholipidscholesterol glycolipids
phospholipids
bilayer with hydrophilic heads on the outside and hydrophobic heads on the inside
amphipatic
both hydrophilic and hydrophobic
integral proteins
span the cell membrane and can form channels, transporters, receptors, while others are enzymes
peripheral proteins
attached to either the outer or inner surface of the cell membrane & form cytoskeletal anchors or act as enzymes
functions of a cell membrane
Communication Shape & protectionSelective permeability
maintenance of electrochemical gradient
the cell membrane creates both a chemical and electrical gradient across the membrane
What kind of entities contribute to the development of the electrical gradient across the membrane?
ions and other charged molecules
simple diffusion
Movement of molecules from a region of high concentration to an area of low concentration: does not require an input of energy, a cell membrane, or transport/carrier proteins
facilitated diffusion
Movement of molecules from a region of high concentration to an area of low concentration: does not require an input of energy, but does require transport/carrier proteins in the cell membrane
osmosis
Movement of water molecules or solvent molecules from a region of high water concentration to an area of low water concentration: does not require an input of energy, does not require pores in the cell membrane
active transport
Movement of molecules from a region of low concentration to an area of high concentration: does require and input of energy & transport/carrier proteins in the cell membrane
endocytosis
Transport of large molecules into the cell due to the �engulfing� action of the cell membrane & the subsequent formation of a membrane bound vesicle
Phagocytosis
�cellular eating� of solid matter
pinocytosis
�cellular drinking� of predominantly extracellular fluid
Exocytosis
Reverse of endocytosis - secretory vesicles formed within the cell fuse with the cell membrane, emptying their contents into the extracellular environment
Receptor-mediated endocytosis
specific pathway in which a molecule must bind to a specific receptor in the cell membrane to initiate an endocytotic event. Once within the cell, the receptors & molecules separate with the receptors returning to the cell membrane, while the specific molecules are processed
cytoplasm
all cellular contents between the cell membrane & the nucleus - it includes the cytosol, organelles
cytosol
thick fluid composed of 75% - 90% water with the remaining composed of soluble & insoluble molecules & ions
organelles
organs" of cells that have specific functions
nucleus
�Control center� of a cell, contains hereditary material (DNA) arranged as genes on chromosomesSurrounded by a double-membrane nuclear envelope which contain nuclear pores to allow the movement of moleculesbetween the cytoplasm & nucleusContain nucleoli for the assembly of ribosomes necessary for protein synthesis
ribosomes
Composed of ribosomal RNA (rRNA) & proteins Sites for protein synthesis May be free-floating in the cytoplasm or bound to endoplasmic reticulum
endoplasmic reticulum
Smooth ER is continuous with the nuclear envelope & is involved in Reticulum (ER) lipid metabolism & detoxification Rough ER has ribosomes attached to it & is involved in modification, storage, & transportation on proteins
golgi complex
Composed of flattened, stacked sacs called cisternae It processes, sorts, packages, & delivers proteins & lipids to the plasma membrane & forms lysosomes & secretory vesicles
protein route for exocytosis
ribosomes, RER, transport vesicles, Golgi complex, secretory vesicles, exocytosis
lysosomes
Contain digestive enzymes Digestion includes processes such as autophagy - digestion of organelles & autolysis - digestion of their host cell
peroxisomes
Contain oxidizing enzymes, like catalaseDetoxification function
mitochondria
Site for cellular respiration, production of ATP
cytoskeleton
Cellular shape & movement
flagella
Long, whip-like structure for movement
cilia
Short, hair-like structures for movement
centrioles
Forms the mitotic spindle for cell division & is involved in the formation & regeneration of flagella & cilia
cell cyle
interphase and mitosis
interphase
Composed of G1, S, & G2 phasesGrowth & preparation for division (mitosis) occur during the G phasesDNA replication occurs during the S phase
Mitosis
Prophase, Metaphase, Anaphase, & Telophase
prophase
chromosomal condensation, nuclear envelopedisintegration, and spindle formation
metaphase
�lining up� of the chromatid pairs on the metaphase (equatorial) plate
anaphase
chromatid separation
telophase
reverse of prophase