Final - Midterm 2 Flashcards
how to manipulate differential centrifugation that results in the largest particles forming a pellet first
an initial slow centrifuge spin for a short amount of time
when viewing cells on a microscope, what happens when the wavelength of light hitting the cells on a slide is decreased:
the resolution of the cells is increased
microsomes:
the small vesicles that are formed when cells are homogenized, the ER is fragmented and self seals
what are 4 parts of the endomembrane system
- lysosomes
- rough ER
- smooth ER
- golgi complex
constitutive secretion:
production and transport of materials in secretory vesicles which occurs continuously
cell-free system:
studies of cell physiology that occur in test tubes that do not contain whole cells
what determines the function of a cell’s smooth ER
protein content
autophagy:
the process responsible for organelle turnover in the cell and for the carrying out of regulated destruction of the cell’s own organelles for the purpose of recycling the components of which they are made
cisternal maturation model:
suggests that the golgi cisternae are transient structures that form at the cis face of the stack by fusion of membranous carriers from the ER and that each cisterna travels through the golgi complex from the cis to the trans end of the stack, changing in conformation as it progresses
what takes place in the golgi apparatus
- O-linked glycosylation
- post-translational processing of the Oligosaccharide precursor
- sorting for transport to other sites in the cell
using genetic engineering techniques, which of the following would you do to a protein that is normally constitutively secreted to make it accumulate in the ER
add a KDEL sequence to its C-terminus
fusion of late endosomes containing intralumenal vesicles with a lysosome leads to:
the degradation of the contents of late endosomes by lysosomal endosomes
clathrin:
is a protein that coats vesicles that contain lysosomal enzymes as they are transported from the TGN
if newly synthesized lysosomal acid hydrolases are secreted from the cells rather than being delivered to the lysosomes, what is the most likely reason:
phosphorylated mannose is not added in the cis golgi network
which molecules do that AP2 adaptors in a clathrin coat complex connect
the cytoplasmic tails of specific membrane receptors and clathrin molecules
carbohydrate chains attached to integral membrane proteins are thought to shield:
lysosomal membranes against attack by their enclosed enzymes
substances the enter the cell by receptors-mediated endocytosis bind receptors that collect in specialized domains of the plasma membrane called:
coated pits
in an otherwise normally functioning cell, the what impact would the absence of clathrin have on the LDL receptor
would inhibit internalization of the LDL receptor
what are the differences between ribosomes that make secretory proteins and those that make proteins intended for the cytosol
there are no differences
what effect does the binding of the SRP to the growing polypeptide chain and the ribosome have on protein synthesis
protein synthesis ceases temporarily
how do integral membrane proteins enter the lipid bilayer
the translocan channel has a gate that continuously opens and closes, giving each nascent polypeptide segment a chance to partition itself into the lipid bilayer’s hydrophobic core
to what residue of a polypeptide are N-linked oligosaccharide chains attached as that polypeptide enters the RER lumen through the translocan
asparagine
what happens if the unfolded protein response (UPR) is unsuccessful in relieving the stressful conditions in the cell
apoptosis is triggered and the cell is destroyed
proteasomes:
responsible for destroying misfolded proteins in the cytoplasm
with respect to proteins that are synthesized in the cytosol but then must be imported into the mitochondrial matrix:
- they must be unfolded
- they will transit through two import complexes
- they will have a signal sequence that directs them to mitochondria
what would happen to the movement of vesicles toward their eventual target if a microtubule inhibitor like colchicine were added to the cells
vesicle movement would slow or stop
vesicles move along microtubules by attaching to microtubules via
motor proteins
noncovalent interactions:
are thought to hold microtubular structure together
in cell biology with respect to microtubules, the term ‘dynamic’ means:
ever-changing in structure
hydrolysis of ATP:
is the direct source of energy that powers molecular motors
