BIOL 221 Lecture Exam 2 UWEC

iron accumulation in the liver

Hemochromatosis

The phospholipid bilayer is _____

semi-fluid

amphipathic; hydrophobic

Cholesterol is _____ & _____

within; within

Lipids can rotate _____ the plane of the phospholipid bilayer, (within/between) leaflets

in their own

Lipids can move laterally (in their own/between) leaflets

flippase

Movement between leaflets requires the _____ enzyme

glycosphingolipids

contain carb groups attached to fatty acid tails that don't have many C=O, so they aren't kinked

endocytosis and cell signaling

Lipid rafts are involved in

across leaflets

Transmembrane proteins allow movement

nonpolar amino acids

Transmembrane proteins contain

lipids; amino acid

Lipid-anchored proteins have _____ covalently attached to an ________ side chain

fatty acid tails

In lipid-anchored proteins, _____ insert into the hydrophobic portion of the membrane

non-covalent; phospholipid polar heads

In peripheral membrane proteins, (covalent/non-covalent) bonds form with either transmembrane proteins or with ______

plasma membrane

Cell adhesion in membrane proteins: proteins in the ________ of adjacent cells hold the cells together

proteins

Membrane transport in membrane proteins: _____ in the plasma membrane allow the transport of substances in and out of cells

extracellular signal; signal cascade; cellular response

Cell signaling in membrane proteins: an ___________ binds to a receptor that activates a ______, leading to a _______

-cell adhesion

-cell signaling

-membrane transport

Membrane protein functions

more

Protein movement is (more/less) restricted than lipid movement in the membrane

larger; slowly

Transmembrane proteins are much (larger/smaller) than phospholipids, so they move much more (fast/slowly)

-phospholipid composition

-presence of cholesterol

What affects membrane fluidity?

selective permeability

only some ions and molecules can move through the plasma membrane

down

Diffusion; movement of a solute (down/up) its gradient

isn't

Diffusion; transport protein (is/isn't) needed

passive

Diffusion is a type of (active/passive) transport

-size

-polarity

-charge

-concentration

What are the four characteristics that determine whether molecules can cross the membrane by DIFFUSION?

faster; more

Diffusion (Size); smaller molecules tend to diffuse (faster/slower), and are (more/less) likely to be able to diffuse

faster; more

Diffusion (Polarity); nonpolar molecules are (faster/slower) and are (more/less) likely to be able to diffuse

more

Diffusion (Charge); neutral molecules are (more/less) likely to diffuse

faster

Diffusion (Concentration); the rate of movement is (faster/slower) when solute concentration is higher on one side of the membrane versus the other

down

Facilitated diffusion; movement (up/down) gradient

is

Facilitated diffusion; transport protein (is/isn't) necessary

passive

Facilitated diffusion is a type of (active/passive) transport

against

Active transport; movement (with/against) a gradient

with

Active transport occurs (with/without) the help of a transport protein

limiting ATP access

Active transport can be shut down by

higher on one side of the membrane than the other

In a concentration gradient, the concentration of a solute is...

in

Na+ moves (in/out) of the cell

out

K+ moves (in/out) of the cell

solute concentrations

Movement of water is dependent on _______

no net movement of water across the membrane

Osmosis; when the outside is isotonic to the inside, there will be ____

movement of the water toward the outside

Osmosis; when the outside is hypertonic to the inside, there will be _____

movement of the water toward the inside

Osmosis; when the outside is hypotonic to the inside, there will be _____

higher; lower

Water moves from (higher/lower) concentration to a region with (higher/lower) concentration

shrinkage

Osmosis; crenation means

rupture

Osmosis; osmotic lysis means

shrink

Osmosis; when placed in a hypertonic solution, cells will

rupture

Osmosis; when placed in a hypotonic solution, cells will

cholesterol

Lipid rafts usually have a high amount of

less;more

When lipids have shorter tails, they are (more/less) likely to interact with one another, making the membrane (more/less) fluid

more

More double bonds means (more/less) fluidity

short and rigid

The presence of cholesterol stabilizes the membrane because it is

down

During osmosis, water moves (up/down) its concentration gradient

aquaporins

Water channels in the plasma membrane that allow faster movement of water

channels

Transmembrane proteins that form a pore or passageway through the membrane

can

Channels (can/cannot) open and close

doesn't

Channels; the movement of a substance (does/doesn't) require the channel to change confirmation

fast

Channels are (fast/slow)

down

Channels always move substances (down/up) the gradient

transporters

Specific binding pockets for the molecule(s) being transferred

do

Transporters (do/don't) have to change confirmation

conformational changes

When a molecule is moved across the membrane via a transporter, the transporter must undergo a series of _____

slow

Transporters are (slow/fast)

uniporter

A carrier protein that transports a single molecule across the plasma membrane.

symporter

transporter that carries two different ions or small molecules, both in the same direction

antiporter

transporter that carries two ions or small molecules in different directions

hydrophilic

Channel gating provides a route through the membrane for (hydrophilic/hydrophobic molecules)

ligands

Channel gating is controlled by the binding of _____ like hormones and neurotransmitters

voltage/mechanical force

Some channel gates are controlled by

hydrophilic

Transporters have a binding pocket that is (hydrophobic/hydrophilic) and provide and hydrophilic environment for the ligand to pass through the membrane

sugars, amino acids, nucleotides, hormones, neurotransmitters, and waste products

Transporters move things like _____,_____,_____,_____,_____,_____ though the membrane

single molecule

Uniporters bind and move a ______ across the membrane

faster

Uniporters; the transport of a molecule is (faster/slower) than had the molecule diffused across the membrane

down

Uniporters; (up/down) the gradient

reversible

Uniporters are (reversible/irreversible)

two or more; same

Symporters move ______ substances across the membrane, in the _____ direction

secondary active

Symporters use ______ transport

two or more; opposite

Antiporters move ______ substances across the membrane in the _____ direction

secondary active

Antiporters use _______ transport

direct; ATP

Primary Active Transport uses ___ acquisition of energy from ____

ATP, terminal phosphate group, against

Pumps in primary active transport bind to ____ and use the energy from hydrolysis of the _________ of ATP to power movement of ions or small molecules (with/against) gradients

plasma membrane

Na+/K+-ATPase are located in the ________ of all animal cells

cytosol; hydrolyzed; ADP; Pi; E2

Na+/K+-ATPase; Step 1; 3Na+ bind from the ________. ATP is ______. ___ is released and _____ is covalently attached to the pump, switching it to the ___ confirmation

Na+

Na+/K+-ATPase; Step 2; 3 ___ are released from outside of the cell

K+

Na+/K+-ATPase; Step 3; 2 __ bind from outside of the cell

Phosphate; E2; cytosol

Na+/K+-ATPase; Step 4; _____ is released and the pump switches to the __ confirmation. 2 __ are released into the ____. The process repeats

take up nutrients and export waste products

Electrochemical Gradients; transport of ions and molecules; symporters and antiporters use H+ and Na+ gradients to _____

synthesize ATP

Electrochemical Gradients; production of energy intermediates; in the mitochondrion and chloroplast, H+ gradients are used to ____

cytosol; extracellular fluid

Electrochemical Gradients; osmotic regulation; animal cells control their internal volume by regulating ion gradients between the _____ & _____

action potentials

Electrochemical Gradients; neuronal signaling; Na+ & K+ gradients are involved in conducting _____

muscle fibers to contract

Electrochemical Gradients; muscle contraction; Ca2+ gradients regulate the ability of _______

bacterial flagella

Electrochemical Gradients; bacterial swimming; H+ drive the rotation of _______

sucrose

Primary and Secondary Active Transport can be coupled to move ______ against the concentration gradient to a cell

protein coat

Exocytosis; Step 1; A vesicle loaded with cargo is formed as a ________ wraps around it

Golgi

Exocytosis; Step 2; A vesicle is released from the _____ carrying cargo molecules

coat is shed

Exocytosis; Step 3; ____

plasma membrane

Exocytosis; Step 4; vesicle fuses with ______ and releases cargo outside

bind to the membrane; invaginates; a vesicle to form

Receptor-Mediated Endocytosis; Step 1; Cargo binds to receptor, receptors aggregate and cause the coat proteins to _________. The plasma membrane ________ as coat proteins cause ______

vesicle

Receptor-Mediated Endocytosis; Step 2; ____ is released into the cell

coat is shed

Receptor-Mediated Endocytosis; Step 3; __

internal organelle

Receptor-Mediated Endocytosis; Step 4; Vesicle fuses with an ________, such as a lysosome