Chapter 2

regulates the passage of substances into and out of the cell

lipids and proteins

• phospholipids
• cholesterol
• glycolipids

bilayer with hydrophilic heads on the outside and hydrophobic heads on the inside

both hydrophilic and hydrophobic

span the cell membrane and can form channels, transporters, receptors, while others are enzymes

attached to either the outer or inner surface of the cell membrane & form cytoskeletal anchors or act as enzymes

• Communication
• Shape & protection
• Selective permeability

the cell membrane creates both a chemical and electrical gradient across the membrane

ions and other charged molecules

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

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

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

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

Transport of large molecules into the cell due to the “engulfing” action of the cell membrane & the subsequent formation of a membrane bound vesicle

“cellular eating” of solid matter

“cellular drinking” of predominantly extracellular fluid

Reverse of endocytosis - secretory vesicles formed within the cell fuse with the cell membrane, emptying their contents into the extracellular environment

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

all cellular contents between the cell membrane & the nucleus - it includes the cytosol, organelles

thick fluid composed of 75% - 90% water with the remaining composed of soluble & insoluble molecules & ions

"organs" of cells that have specific functions

• “Control center” of a cell, contains hereditary material (DNA) arranged as genes on chromosomes
• Surrounded by a double-membrane nuclear envelope which contain nuclear pores to allow the movement of molecules
• between the cytoplasm & nucleus
• Contain nucleoli for the assembly of ribosomes necessary for protein synthesis

• Composed of ribosomal RNA (rRNA) & proteins
• Sites for protein synthesis
• May be free-floating in the cytoplasm or bound to 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

• Composed of flattened, stacked sacs called cisternae
• It processes, sorts, packages, & delivers proteins & lipids to the plasma membrane & forms lysosomes & secretory vesicles

ribosomes, RER, transport vesicles, Golgi complex, secretory vesicles, exocytosis

Contain digestive enzymes

Digestion includes processes such as autophagy - digestion of organelles & autolysis - digestion of their host cell

• Contain oxidizing enzymes, like catalase
• Detoxification function

Site for cellular respiration, production of ATP

Cellular shape & movement

Long, whip-like structure for movement

Short, hair-like structures for movement

Forms the mitotic spindle for cell division & is involved in the formation & regeneration of flagella & cilia

interphase and mitosis

• Composed of G1, S, & G2 phases
• Growth & preparation for division (mitosis) occur during the G phases
• DNA replication occurs during the S phase

Prophase, Metaphase, Anaphase, & Telophase

• chromosomal condensation, nuclear envelope
• disintegration, and spindle formation

“lining up” of the chromatid pairs on the metaphase (equatorial) plate

chromatid separation

reverse of prophase