|Chapter 6 - Cell Transport| Flashcards
what is homeostasis?
the need of an organism to keep and regulate a constant internal temperature-
temperature, pH, and concentration of other materials have to be maintained within a pretty narrow margin
much of homeostasis is determined by ______
the CELL MEMBRANE controlling movement of things in and out of the cell
list 3 parts of the cell membrane
hydrophilic region - water loving
hydrophobic region - water fearing
transport protein
what is SELECTIVELY PERMEABLE?
certain substances pass through freely, while others must move through a “gate”
what can transport of materials be classified as?
either PASSIVE TRANSPORT or ACTIVE TRANSPORT
what is the cell membrane made of?
how is it arranged?
PHOSPHOLIPIDS aka the phosphate “head” + 2 fatty acid chain “tails”`
it’s arranged in a BILAYER …… POLAR heads (phosphate “head”) = HYDROPHILLIC ….. NONPOLAR tails ( 2 fatty acid chain “tails” ) = HYDROPHOBIC
what materials can and can’t pass easily in SELECTIVE PERMEABILITY?
can pass easily = small - nonpolar - hydrophobic - neutral molecules …. water ( h20 is polar but really tiny(
cannot pass easily = polar molecules (must go through proteins) …. large molecules (must use vesicles)
passive transport
- no extra energy needed BECAUSE molecules move from high concentration (squished together) to low concentration ( spread out) areas DOWN the concentration gradient
ACTIVE TRANSPORT
NEED extra energy (ATP) to bring materials into the cell or expel materials out of the cell moving from low concentration to high concentration AGAINST the concentration gradient
CONCENTRATION?
Number of molecules of a substance in a given volume
CONCENTRATION GRADIENT
Difference in concentration of a substance from one location to another
examples of passive transport
- diffusion
- osmosis
- facilitated diffusion
examples of ACTIVE TRANSPORT
- molecular pumps
- exocytosis
- endocytosis
DIFFUSION? ( active or passive? … def .. what happens? .. examples? )
PASSIVE TRANSPORT
The spreading out of molecules across a membrane until they’re equally concentrated on both sides of the membrane.
molecules move down a concentration gradient, from high area to low area
example - OXYGEN and CARBON DIOXIDE
FACILITATED DIFFUSION ( active or passive? … def .. what happens? .. examples? )
PASSIVE TRANSPORT
a TRANSPORT PROTEIN acts as a protein channel to help ( facilitate) the diffusion of molecules that normally couldn’t pass through the cell membrane ( LARGE MOLECULES AND POLAR MOLECULES)
molecules move down a CONCENTRATION GRADIENT, from high to low- SO NO ATP NEEDED
example: glucose/sugar,,,, sodium/salt
OSMOSIS ( active or passive? … def .. what happens? .. examples? )
PASSIVE TRANSPORT
the diffusion of WATER across the cell membrane
WATER MOLECULES MOVE down a CONCENTRATION GRADIENT, from high to low
OSMOSIS?
LOW OSMOTIC PRESSURE?
osmosis = diffusion of water from high to low
low osmotic pressure = low solute = high water = HYPOTONIC
HIGH osmotic pressure?
= high solute = low water = hypertonic
SOLUTE? SOLVENT? SOLUTION? CONCENTRATION?
solute + solvent = solution …. concentration = solute/solvent
example: osmosis:
1 solution on either side of semi-permeable membrane…. SOLUTION A - CONCENTRATED SUGAR SOLUTION -> SOLUTION B - DILUTE SIGAR SOLUTION …. both contain a mix of sugar and water (equal water, more sugar in A ) molecules ….. -»» osmosis -»> more water is drawn into the concretated solution (more water + sugar in A)
ISOTONIC
equal amount of solute on both sides of membrane (cell stays the same - animal, flaccid - plant)
HYPOTONIC
has too much water; can lyse (swells - animal, normal - plant)
HYPERTONIC
has too little water; can shrivel ( crenate - animal, plasmolyzed - plant)
if a cell is 20% NaCl and 80% H20 within a 10% NaCl and 90% H20 environment, the cell is in a _____ solution and will ____
HYPOTONIC, SWELL
if a cell is 5% NaCl and 95% H20 within a 15% NaCl and 85% H20 environment, the cell in a _____ solution and will _____
HYPERTONIC, SHRIVEL
If a cell is 10% NaCl and 90% H20 within a 10% NaCl and 90% H20 environment, the cell is in a ______ solution and will ______
ISOTONIC, STAY THE SAME
How are gases exchanged in single celled organisms?
Gases exchanged by diffusion in 1-cell organisms diffuse directly into the water.
How are gases exchanged in multi-celled organisms?
Multi-celled organisms require special structures with large surface area.
Example -> gills in fish, lungs in animals, spiracles in insects, stomates in plants
How does air travel in humans?
air travels from GAS EXCHANGE
nose -> pharynx -> tracheae -> bronchi -> alveoli (60m^2) -> lungs
how is waste excreted by single-celled organisms?
waste excretion also needs special structures ,,,
contractile vacuoles in 1 cell organisms
how is waste excreted in animals?
kidneys,,
animal cells are bathed in blood- kidneys keep the blood isotonic by removing excess salt and water
how is waste excreted in humans?
blood plasma filtered by NEPHRONS in kidneys, (after reabsorption of Na, K, and water) -> ureter -> urinary bladder -) urethra and out of body
ACTIVE TRANSPORT?
some molecules have to be pushed “uphill”, against a concentration gradient - needs ATP
substances are moving from LOW TO HIGH concentration
or substances are TOO BIG to move through a protein channel; and have to be enveloped by the cell or excreted by the cell by endocytosis or exocytosis.
ENDOCYTOSIS? ( active or passive? … def .. what happens? .. examples? )
ACTIVE
a cell USES ENERGY to IMPORT large amounts of molecules INTO the cell using a vesicle
example - white blood cells engulf bacteria to fight infection
ENDOCYTOSIS (2 types)( active or passive? … def .. what happens? .. examples? )
ACTIVE
PHAGOCYTOSIS - cell “eating”… cell engulfs SOLIDS into vesicle and “digests” them
PINOCYTOSIS - cell “drinking” … cell engulfs LIQUIDS into vesicle and “digests” them
EXOCYTOSIS
ACTIVE
A cell USES ENERGY to EXPORT large amounts of materials OUT OF the cell using a VESICLE
Example - Nerve cells release neurotransmitters to pass signals to the brain
MOLECULAR PUMPS
ACTIVE
When a cell USES ENERGY to pump molecules across the membrane through a PROTEIN CHANNEL
This allows a cell to concentrate key molecules within the cell or remove waste quickly from the cell.
Example - Calcium (Ca^2+), potassium (k+), chlorine (Cl-), and sodium (Na+) = ions (charged particles)
