Organelles 1

What does amphipathic mean

containing polar and non-polar segments

What can travel through the phospholipid membrane without assistance

small nonpolar molecules and uncharged polar molecules

What is a membrane’s transition temperature in reference to?

The specific temperature at which a lipid bilayer shifts its physical state from a highly ordered, rigid gel phase to a disordered, fluid liquid-crystalline phase

What determines the transition temperature of a membrane

the lipid composition

What effect does cholesterol have on the membrane

Reduced membrane fluidity, increased
membrane integrity, reduced temperature sensitivity

Where does cholesterol pack in the membrane

with unsaturated fatty acids

How does fatty acid saturation of the lipids within the membrane affect rigidity

unsaturated fatty acids kink, reduce lipid density, increasing fluidity

What allows membranes to repair

they can move laterally

Aside from repair, what else does lateral fluidity allow

membrane fusion

What does the extracellular matrix allow for

protection, hold cells together in tissues

What does it mean to be gram-positive

One lipid bilayer with a thick outer peptidoglycan shell

What does it mean to be gram-negative

Two lipid bilayers with a thin peptidoglycan shell between the bilayers

What cells have the extracellular matrix

animal cells

What’s the difference between heterochromatin and euchromatin

heterochromatin = dark staining

euchromatin = light staining

Where are ribosomes made

inside the nucleolus

What is the nuclear pore made of

large complex of several proteins that span the nuclear envelope

Why is a positive control used

to confirm that the setup is working correctly and capable of producing a known, expected result

Why is a negative control used

to establish a baseline, ensuring that results are caused by the experimental treatment rather than external factors or contamination