Movements Through Cell Membrane Flashcards Preview

Anatomy and Physiology > Movements Through Cell Membrane > Flashcards

Flashcards in Movements Through Cell Membrane Deck (27):
1

passive transport

-Physical process that requires no cellular energy

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4 examples of passive transport

-Simple diffusion
-facilitated diffusion
-osmosis
-filtration

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Active transport

Physiological process that requires energy

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3 examples of active transport

-endocytosis
-exocytosis
-transcytosis

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Simple diffusion

Movement of substances from regions of higher concentration to regions of lower concentration (no energy required)

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In what 3 substances does simple diffusion occur?

Oxygen, carbon dioxide, and lipid-soluble substances

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What is another way to explain going from high concentration to low concentration?

Going down/along the concentration gradient

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Facilitated Diffusion

Diffusion across a membrane with help of a channel or carrier molecule (no energy required)

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Phenomenon

Event you observe; either good/bad

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Saline

salt

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Osmosis

Simple diffusion; movement of water through a selectively permeable membrane from regions of higher concentration to regions of lower concentration.

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In what direction does water move during osmosis?

Toward a higher concentration of solutes; (high concentration of WATER to low concentration of WATER)

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Osmotic Pressure

Ability of osmosis to generate enough pressure to move a volume of water

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Osmotic pressure _____________ as the concentration of non permeable solutes increases

Osmotic pressure INCREASES

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Isotonic

Same osmotic pressure

RBC: normal physiological saline (0.85% NaCl)

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Hypertonic

Higher osmotic pressure

RBC: crenation (i.e., 1.5% NaCl)

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Hypotonic

Lower osmotic pressure

RBC: hemolysis (i.e., 0.25% NaCl)

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Filtration

Smaller molecules are forced through porous membranes.

Hydrostatic pressure is important in the body

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Hydrostatic pressure

Pressure a fluid exerts on the wall of its container

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Filtrate

Substances you collect after filter

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Active transport

*Requires energy (ATP)

Carrier molecules transport substances across a membrane from regions of lower concentration to regions of higher concentration

(against concentration gradient)

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What molecules are usually involved in active transport? (4)

Sugars, amino acids, sodium ions, potassium ions

Molecules the cell really needs

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Endocytosis

Cell engulfs a substance by forming a vesicle around the substance

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Receptor-mediated endocytosis

requires the substance to bind to a membrane-bound receptor

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What are two factors that affect the rate of diffusion?

1. Temperature (warmer=happen faster)
2. Size

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Exocytosis

Reverse of endocytosis
Substances in a vesicle fuse with cell membrane; contents released outside of the cell

i.e., release of neurotransmitters from nerve cells

27

Transcytosis

Endocytosis followed by exocytosis; transports a substance rapidly through a cell

i.e., HIV crossing a cell layer