BIO 141 - CLASS - CHPT 3: PLASMA/CELL MEMBRANE - part 2

Na+ diffusion favored by concentration (chemical) gradient and electrical gradient

Cl- diffusion favored by the concentration but not by the electrical gradient

Na+ high concentration
Cl- high concentration

- transport of glucose, amino acids, and ions
- transported substances bind carrier proteins or pass through protein chanells

Who is helping it? some sort of protein

- are integral transmembrane proteins
- show specificity for certain polar molecules including sugars and amino acids

*are specific for what they do

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- occurs when the concentration of a solvent is different on opposite sides of a membrane.
- diffusion of water across a semipermeable membrane.
- osmolarity
- tonicity

total concentration of solute particles in a solution
(in water)

how a solution affects cell volume

- the passage of water and solutes through a membrane by hydrostatic pressure
- pressure gradient pushes solute-containing fluid from a high-pressure area to a lower-pressure area

- Affect of total solute concentration in a water solution

- things to remember:
ISO = equal
HYPER = high
HYPO = low
(all indicate how much solute in the solutions)
not referring to how much water you have

solutions with the SAME solute concentration as that of the cytosol

transport of large particles and macromolecules across plasma membranes

moves substance from the cell interior to the extracellular space. "EXIT"

enables large particles and macromolecules to enter the cell. "in"

moving substances into, across, and then out of a cell. "IN AND OUT"

moving substances from one area in the cell to another

pseudopods engulf solids and bring them into the cell's interior

(white blood cells do this)

the plasma membrane infolds, bringing extracellular fluid and solutes into the interior of the cell

clathrin-coated pits provide the main route for endocytosis and transcytosis

caveolae that are platforms for a variety of signaling molecules

Kinetic Energy (KE)

Movement of O2 through membrane

KE

Movement of glucose into cells

KE

Movement of H2O in and out of cells

Hydrostatic pressure

Formation of kidney filtrate

ATP

Movement of ions across membranes

ATP

Neurotransmitter secretion

ATP

White blood cell phagocytosis

ATP

Absorption by intestinal cells

ATP

Hormone and cholesterol uptake

ATP

Cholesterol regulation

ATP

Intracellular trafficking of molecules

- voltage across a membrane
- resting membrane potential
- steady state

the point where K+ potential is balanced by the membrane potential
- ranges from -20 to -200 mV
- results from Na+ and K+ concentration gradients across the membrane
- differential permeability of the plasma membrane to Na+ and K+

potential maintained by active transport of ions

- anchor cells to the extracellular matrix
- assist in movement of cells past one another
- rally protective white blood cells to injured or infected areas

1. contact signaling
2. electrical signaling
3. chemical signaling
4. G protein-linked receptors

important in normal development and immunity

voltage-regulated "ion gates" in nerve and muscle tissue

neurotransmitters bind to chemically gated channel-linked receptors in nerve and muscle tissue

ligands bind to a receptor while activates a G protein, causing the release of a second messenger,s uch as cyclic AMP

ATP

Intracellular trafficking of molecules

- voltage across a membrane
- resting membrane potential
- steady state

the point where K+ potential is balanced by the membrane potential
- ranges from -20 to -200 mV
- results from Na+ and K+ concentration gradients across the membrane
- differential permeability of the plasma membrane to Na+ and K+

potential maintained by active transport of ions

- anchor cells to the extracellular matrix
- assist in movement of cells past one another
- rally protective white blood cells to injured or infected areas

1. contact signaling
2. electrical signaling
3. chemical signaling
4. G protein-linked receptors

important in normal development and immunity

voltage-regulated "ion gates" in nerve and muscle tissue

neurotransmitters bind to chemically gated channel-linked receptors in nerve and muscle tissue

ligands bind to a receptor while activates a G protein, causing the release of a second messenger,s uch as cyclic AMP

- an extracellular ligand (first messenger), binds to a specific plasma membrane protein
- the receptor activities a G protein that relays the message to an effector protein

enzyme that produces a second messenger inside the cell

activates a kinase

can trigger a variety of cellular responds

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material between plasma membrane and the nucleus

largely water with dissolved protein, salts, sugars, and other solutes

metabolic machinery of the cell

chemical substances such as glycosomes, glycogen granules, and pigment

- specialized cellular compartments
- membranous
- nonmembranous

mitochondria, peroxisomes, lysosomes, endoplasmic reticulum, and golgi aparatus

cytoskeleton, centrioles, and ribosomes

- double membrane structure with shelf-like cristae
- provide most of the cell's ATP via aerobic cellular respiration
- contain their own DNA and RNA

- granules containing protein and rRNA
- site of protein synthesis
- free ribosomes sythesize soluble proteins
- membrane-bound ribosomes synthesize proteins to be incorporated into membranes

- interconnected tubes and parallel membranes enclosing cisternae.
- continuous with the nuclear membrane.
- two varieties - rough ER and smooth ER

- external surface studded with ribosomes
- manufactures all secreted proteins
- responsible for the synthesis of integral membrane proteins and phospholipids for cell membranes

- mRNA
- SRP is released and polypeptide grows into cisternae
- the protein is released into the cisternae and sugar groups are added
- the protein folds into a 3-dimesional conformation
- the protein is enclosed in a transport vesicle and moves toward the golgi apparatus

ribosomes complex is directed to rough ER by a signal-recognition particle (SRP)

- tubules arranged in a looping network

- in the liver- lipid and cholesteral metabolism, breakdown of glycogen and, along with the kidneys, detoxification of drugs.
- In the testes - synthesis of steroid-based hormones
- In the intestinal cells - absorption, synthesis and transport of fats
- In skeletal and cardiac muscle - storage and release of calcium