lesson 5 Flashcards
Proteins exit from the ______ in transport vesicles destined for either the _____ _______ or another organelle of the endomembrane system.
golgi, cell surface
______ cells isolate and organize their chemical reactions by aggregating proteins into multicomponent complexes that form biochemical ____________ with distinct _______.
prokaryotic, subcompartments, functions
Transport vesicles carry ____ _____ proteins as well as other proteins and lipids that are part of the ______ membrane from one organelle to another.
soluble cargo, vesicle
How do the interiors of the ER, Golgi apparatus, endosomes, and lysosomes communicate with each other?
a. by small vesicles that bud off of one organelle and fuse with another
Where are most mitochondrial and chloroplast proteins made within the cell?
cytosol
True or False: Proteins that are made in the cytosol and have NO signal sequence will remain in the cytosol rather than being excreted.
true
True or False: The fate of any protein molecule synthesized in the cytosol depends on its amino acid sequence, which can contain a sorting signal that directs the protein to the organelle in which it is required.
true
The _____ ________ signal on proteins destined for the nucleus is recognized by cytosolic proteins called _____ ______ receptors.
nuclear localization, nuclear import
____ _____ ____ help direct a newly synthesized protein to a nuclear _____ by interacting with the tentacle-like _____ that extend from the rim of the pore into the cytosol.
nuclear import receptors, pore, fibrils
True or False: The ER serves as a passing point for proteins destined for the golgi, endosomes, cell surface AND lysosomes.
true
The _____-_____ sequence anchors the protein into the membrane.
stop-transfer
Eventually a stop-transfer sequence forms a _-_______ membrane-spanning segment of the protein.
alpha-helical
The movement of materials from the plasma membrane, through endosomes, and then to lysosomes describes which type of pathway?
endocytic
Proteins that play a central role in the fusion of a vesicle with a target membrane are called what?
SNAREs
By winding around each other tightly, ______ proteins pull the membrane _____ close enough to allow their ____ to flow together.
SNARE, bilayers, lipids
Newly made lipids are supplied to the plasma membrane via the _____ pathway of _____
constitutive, exocytosis
The process in which large particles like microbes and cell debris are consumed.
phagocytosis
_____ can send material back to the plasma membrane, to a different _____ of the plasma membrane or onto the ______ for _____
endosomes, domain, lysosomes, degradation
Which cellular compartment acts as the main sorting station for extracellular cargo molecules taken up by endocytosis?
endosomes
This part of receptor-mediated endocytosis is the molecules packaged into vesicles for transport.
cargo
This part of receptor-mediated endocytosis is the part that captures the correct cargo molecules.
receptor
This part of receptor-mediated endocytosis is the part that mediated contact between the receptor and another component.
adaptin
This part of receptor-mediated endocytosis is the thing that shapes the forming of vesicles.
clathrin
_______ antibodies recognize the exact same ______ or part of an antigen. They are VERY specific.
monoclonal, epitope
______ antibodies recognize different ______ of the same _____. For example mouse anti-rabbit protein X.
polyclonal, epitopes, antigen
True or False: Internal membrane is present in bacteria and eukaryotic cells.
false, only eukaryotic
Membranes are site of selective ________. We see the import and export of small molecules.
permeability
There are many _____ in the membrane that extracellular _____ are able to bind to on the extracellular portion of it.
receptors, ligands
The membrane is assembled in the ___. Proteins are assembled by the ribosomes based on the order of amino acids from the ______ which is determined by the DNA.
ER, mRNA
True or False: There is no genetic sequence for a lipid; it is just the genetic instructions to build a lipid.
true
Lipids are synthesized in the ER using ____ ____, there are also enzymes that synthesize phospholipids on the ______ face of the ER.
fatty acids, cytoplasmic
Phosphate groups are at the hydro____ region of an amphipathic molecule and they have a ____ charge.
philic, negative
Kinked tails means.
unsaturated
Saturate means _____ tails.
unkinked
The ____ molecule is what is directly attached to the phospholipid tails.
glycerol
During _____ synthesis, water is being removed; we see the phosphate attached to the __ place so instead of the third chain we have a phosphate group.
dehydration, 2
The ____ of lipids allows a bilayer to spontaneously assemble in an aqueous environment. This includes ______ interactions to minimize contact with water and formation of ______ spontaneously.
structure, hydrophobic, micelles
Micelles: tails are on the (outside/inside).
inside
In regards to fluidity, _________ means it contains a double bond and is _____ tightly packed aka _____ fluid.
monounsaturated, less, more
In regards to fluidity, _____ means they are ____ tightly packed and thus ____ fluid.
saturated, more, less
The ____ composition of various organelles are VERY different. Different organelles have their own different mix. As a result, different _____ can associate with these membranes supporting different functions.
lipid, proteins
Lipid composition varies between _____ of membranes because the different ‘–’ have different ______. For example, the plasma membrane, one side has an extracellular face and the other side has an intracellular face.
leaflets, functions
Small nonpolar molecules include what 4 examples from class?
O2, CO2, N2, steroid hormones
Small nonpolar molecules can cross ____.
freely
Small _____ ______ molecules can get across but not as freely as small nonpolar molecules. The partial charges are fairly small.
uncharged polar
3 examples of small uncharged polar molecules from class are what?
H2O, ethanol, glycerol
Examples of large uncharged polar molecules include ___ ___, _____ and ______.
amino acids, glucose, nucleosides
True or False: Large uncharged polar molecules may have nonpolar side chains but are still considered polar because of the backbone.
true
What group cannot cross the membrane freely at all?
ions
Movement of solutes across the membrane without the aid of a protein.
simple diffusion
True or False: Simple diffusion sometimes uses channels or transporters.
false
A form of passive transport that utilizes transport proteins to move solutes across the membrane.
facilitated diffusion
A form of transport that moves solutes across a membrane against their concentration gradient.
active transport
Active transport is carried out by ____ that harvest energy from ATP or an ___ ____ or light.
pumps, ion gradient
______ transport by a _____ does NOT require a conformational change.
facilitated, channel
_____ transport by a _______ DOES require a conformational change.
facilitated, transporter
Water-filled pores through which substrates passively diffuse down their electrochemical gradient. They discriminate solutes based on ____ and _____
channels, size, charge
Undergo a cycle of conformational changes linked to substrate binding and dissociation on opposite sides of the membrane. They bind with great _____
transporters, specificity
What 2 things influence the passive transport of a charged solute across the membrane?
concentration gradient and membrane potential
The membrane is a little _____ closer to the inside of the cell and a little _____ towards the outside of the cell.
negative, positive
Glucose may be moved against its concentration gradient via a sodium _____
gradient
If the sodium potassium gradient didn’t work we would see ____ movement of glucose into the cell.
less
The movement of glucose using the sodium potassium pump is an example of _____ active transport.
secondary
In the example of Ca2+ in muscle cells, we needed ____ for the reuptake process because we would be moving Ca2+ _____ its concentration gradient.
ATP, against
We may perform colocalization if we think a pump is not ____ correctly.
localized
A mutation in the start or stop codon may cause the protein to be _____ incorrectly.
folded
We can perform western blot to see if a protein is _____ and thus the pump is not working correctly.
degraded
