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Biology Study Notes: Osmosis, Diffusion, and Transport Processes, Quizzes of Biochemistry

Definitions and explanations of various terms related to osmosis, diffusion, and transport processes in biology. Topics include osmosis and its effects on cell volume, osmotic pressure, diffusion, factors that control diffusion, facilitated diffusion, active transport, and different types of transport proteins. Understanding these concepts is essential for students of biology and related fields.

Typology: Quizzes

2012/2013

Uploaded on 05/13/2013

amygouldsbrough
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TERM 1
Osmosis
DEFINITION 1
Osmosis is the net movement of water molecules through a
partially permeable membrane from an area of high water
potential to an area of low water potentialhigh water
potential - dilute - lots of waterlow water potential -
concentrated - little waterpermeable to water but not
solutein lipid bilayer or through aquaporins
TERM 2
Osmotic Pressure
DEFINITION 2
Osmotic pressure is the pressure required to prevent the
inward flow of water across a semipermeable membrane.
Osmosis controls cell volumeHypotonic - More H2O enters
cell rather than leaves. Swells and bursts.Hypertonic - More
H20 leaves rather than enters. Shrivels and dies.Isotonic - No
net movement of H20.
TERM 3
Diffusion
DEFINITION 3
Movement of small, non polar particles from an area of high
conc to low conc. Down conc gradient.No ATP required for
simple diffusion due to kinetic energy possessed by
particles.Random movement.
TERM 4
Factors that Control
Diffusion
DEFINITION 4
Conc gradient - Larger gradient - faster diffusionTemp -
Higher temp - faster diffusion (more kinetic energy)Surface
Area - Higher SA - FasterDistance - Smaller distance - Faster
TERM 5
Factors that Control
Diffusion
DEFINITION 5
Size of Solute - Smaller - FasterCharge - No charge - Able,
Charge - Not ablePolarity/Hydrophobicity - Less polar -
FasterO2, CO2, vitamins drugs etc - diffuse through
membrane
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Osmosis

Osmosis is the net movement of water molecules through a partially permeable membrane from an area of high water potential to an area of low water potentialhigh water potential - dilute - lots of waterlow water potential - concentrated - little waterpermeable to water but not solutein lipid bilayer or through aquaporins TERM 2

Osmotic Pressure

DEFINITION 2 Osmotic pressure is the pressure required to prevent the inward flow of water across a semipermeable membrane. Osmosis controls cell volumeHypotonic - More H2O enters cell rather than leaves. Swells and bursts.Hypertonic - More H20 leaves rather than enters. Shrivels and dies.Isotonic - No net movement of H20. TERM 3

Diffusion

DEFINITION 3 Movement of small, non polar particles from an area of high conc to low conc. Down conc gradient.No ATP required for simple diffusion due to kinetic energy possessed by particles.Random movement. TERM 4

Factors that Control

Diffusion

DEFINITION 4 Conc gradient - Larger gradient - faster diffusionTemp - Higher temp - faster diffusion (more kinetic energy)Surface Area - Higher SA - FasterDistance - Smaller distance - Faster TERM 5

Factors that Control

Diffusion

DEFINITION 5 Size of Solute - Smaller - FasterCharge - No charge - Able, Charge - Not ablePolarity/Hydrophobicity - Less polar - FasterO2, CO2, vitamins drugs etc - diffuse through membrane

Hydrophobicity

Dislike of a molecule for H2OMeasured using K = Cm / CaqCm = solubility in membraneCaq = solubility in H2OHigher K = more hydrophobic TERM 7

Facilitated Diffusion (no ATP needed) - passive

DEFINITION 7 Solute binds to protein in membraneMoves down conc gradientSpecific protein for specific soluteSpeed depends on amount of proteins availableSteepness of gradient TERM 8

Kinetics of Passive Transport

DEFINITION 8 Similar to enzyme kineticsVmax = maximum rate of transport1/2 Vmax = half max rateKtr = substrate conc at which 1/2 Vmax is TERM 9

Carrier Proteins used in Facilitated

Diffusion

DEFINITION 9 Undergo conformational changeChannel proteins - hydrophilic pores or ion channelsWhen conc of [S] inside = conc of [S] outsideNo net movementRate inward = rate outward TERM 10

Carrier Proteins

DEFINITION 10 Two conformational states - AllostericTransport one type of molecule - SpecificLimited no available for transport - SaturableUniport or cotransport exists (two molecules)Co transport - passive - conc gradient down used to move other molecule against their conc gradient

ABC transporters

Protein superfamilyUse energy from ATP hydrolysis to transport variety of substrates across membraneDrug is quickly pumped out cells using this method before it has an effect TERM 17

Secondary Active Transport

DEFINITION 17 Uses energy stored in ionic concentration gradientCouples transport of substrate against conc gradient with transport of substrate down conc gradientLactose permease symporter (H+ moves down) (Lactose moves up) TERM 18

Digitalis

DEFINITION 18 Slows action of Na+/K+ pump.Na+ accumulates in heart muscle cells.Smaller Na+ gradient in cellsCa2+ remains in cardiac cellsStrengthens force of cardiac contractionCauses disturbance to heart rhythm etc TERM 19

Vesicular Transport

DEFINITION 19 Vesicle - liquid within another liquid in bubblemembrane enclosed sac used to store, digest or transport materialOne lipid bilayerUseful for transport of proteinendocytosis - moves something into cellexocytosis - moves something out of cell TERM 20

Endocytosis

DEFINITION 20 Phagocytosis - bacteria and virus' engulfed and digested.

Exocytosis

Release of material from cellSecretions from cellVesicle fuses with membrane and releases products (synapses releasing neurotransmitters)Secretion is triggered by extracellular signal TERM 22

Pinocytosis and Phagocytosis

DEFINITION 22 Pinocytosis - lysosome fuses with pinocytic vesicle, digestion with lysosomal enzymes, residual body, exocytosis.No pseudopods form.Phagocytosis - lysosome fuses with phagosome, digestion with lysosomal enzymes, residual body, exocytosis.Pseudopods extend to form phagosome. TERM 23

Receptor Mediated Endocytosis

DEFINITION 23 Required substance binds to receptor protein inclathrincoated pit in cell membrane. Lattice structure of clathrin causes pit.Membrane folds inwards.Vesicle combines with endosome.Ligands digested by lysosomal enzymes or are transported across the cell in the vesicle