Lecture: Chapter 03 Flashcards
CELLS
the basic structural unit of all living organisms
3 MAJOR REGIONS OF CELL
1) Plasma Membrane (a.k.a. Cell Membrane)
2) Cytoplasm
3) Nucleus
- PLASMA MEMBRANE-
p. 64
a.k.a. Cell membrane; outer boundary of a cell; selectively permeable; a phospholipidus bilayer w/ proteins floating in it; hydrophobic(hating), hydrophilic(loving); about 20% of membrane is cholesterol, which stabilizes it; proteins make up about HALF of membrane by mass & are responsible for specialized functions (float in/on membrane itself);proteins coated in carbohydrate called Glycocalyx( a.k.a. “biological markers”) to recognize “self” from “non-self”
SPECIALIZED AREAS
of plasma membrane
1) Microvilli
2) Cilia
3) Flagella
4 FUNCTIONS
of plasma membrane
1) Protection: selectively permeable
2) Transport: in & out of cell
3) Resting Membrane Potential: important in muscles & nerves
4) Cell Environment Interaction: when anything extracellular interacts
MEMBRANE JUNCTIONS
1) Tight junctions
2) Desmosomes
3) Gap junctions
(see following cards)
TIGHT JUNCTIONS
sticks adjacent cells together; permeable.
*Found in: intestines, stomach, bladder.
DESMOSOMES
anchoring junctions
*Found in: skin, heart muscle.
GAP JUNCTIONS
communicating junction; different things can pass through; permeable.
*Found in: heart, smooth muscle
MEMBRANE TRANSPORT
figure 3.9 on page 71
Passive & Active
see following cards
PASSIVE TRANSPORT
does NOT use energy; includes: diffusion, facilitated diffusion, filtration, tonicity, isotonic, hypertonic, hypotonic.
DIFFUSION
movement from area of High concentration to area of Low concentration; diffusion of water called “osmosis.” (PASSIVE)
FACILITATED DIFFUSION
large molecules are piggy-backed across membrane on other molecules. (PASSIVE)
FILTRATION
forces water and solutes through a membrane wall; uses fluid pressure; Not selectively permeable; high pressure to area of low pressure. (PASSIVE)
TONICITY
ability to change shaped cells (tone) by changing internal volume. (PASSIVE)
ISOTONIC
same as tonicity (iso); no net loss/gain of water. (PASSIVE)
HYPERTONIC
Higher concentration of solutes; lose water, shrinks (a.k.a. “Crenation”). (PASSIVE)
HYPOTONIC
Lower concentration of solutes; absorb water, swells. (PASSIVE)
ACTIVE TRANSPORT
requires energy (ATP); moves up a concentration gradient; includes Exocytosis, Endocytosis.
EXOCYTOSIS
stuff to be released from cell is enclosed in vesicle, vesicle fuses w/ membrane, stuff is dumped OUT. (ACTIVE)
ENDOCYTOSIS
3 types: Phagocytosis, Pinocytosis, & Receptor-mediated endocytosis (ACTIVE)
PHAGOCYTOSIS
“cell eating” (phago=to eat); solid stuff taken into cell; EX: Macrophages- cells that dispose of(eat) dead cells.
PINOCYTOSIS
“cell drinking” (pino=to drink); liquids w/ dissolved molecules taken into cell; EX: Absorbative cells, found in kidneys & intestines.
RECEPTOR-MEDIATED ENDOCYTOSIS
similar to phagocytosis except stuff takein in must exactly match receptors on the cell; Allows a cell to take in cholesterol from extracellular fluid.
