Chapter 5 Exam 2 Flashcards
what are the essential features of a cell
can store and transmit info, has a plasma membrane, can harness energy from environment
what is a micelle
ball like structure formed by lipids with a bulky hydrophilic head and a single fatty acid tail
what is a liposome
closed structure with an inner space, no free edges that would expose lipids to the environment
what does the speed of molecules moving within and across a membrane depend on
Temperature and structure of hydrocarbon tails
explain saturated vs unsaturated fatty acids
saturated have no double bonds, unsaturated has double bonds
what does cholesterol do
increases or decreases the fluidity of membrane depending on temperature
what does normal temperatures do to cholesterol
reduces the mobility of phospholipids and fluidity of the membrane
what does lower temperatures do to cholesterol
prevents phospholipids from packing tightly increasing fluidity
what is carrier mediated diffusion
binding of the transporter molecule inducing a conformational change in the carrier membrane protein, allowing the molecule to be transported across the lipid bilayer
what is an antiporter
pump that moves ions in opposite directions
what is an example of an antiporter
sodium potassium pump
what is a symporter
transporter that moves 2 molecules in same direction
what is secondary active transport
using one gradient to drive transport against another
what is hypertonic
cell is shrunk because water leaves and sodium is high outside the cell
what is hypotonic
cell is swollen because water comes in because sodium is high inside
what is a cell wall composed of
polysaccharides
what are vacuoles
water filled organelles that contribute to structural rigidity of plants by maintaining turgor pressure against cell walls
what are chloroplasts
enable plant cells to harness energy from sunlight to synthesize sugars
what makes up the endomembrane system
nuclear envelope, ER, Golgi apparatus, vesicle, lysosome, plasma membraen
what are some characteristics of the nuclear membrane
defines boundary of nucleus, inner and outer membranes. contains nuclear pores
what molecules require active transport through nuclear pores? passive?
active-large proteins and RNA
passive- small molecules and ions
where do proteins made in the cytosol with no signal peptidases go
cytosol
where do proteins made in the cytosol with amino terminal signals go
chloroplast or mitochondrion
where do proteins made in the cytosol with internal signals go
nucleus by a nuclear localization signal
