Question

which lipid - composition gives the least membrane fluidity?
phospholipids with long - chain, unsaturated fatty acids
phospholipids with short - chain, saturated fatty acids
phospholipids with long - chain, saturated fatty acids
phospholipids with short - chain, unsaturated fatty acids

18 multiple - choice 1 point
during ____, large molecules are broken down and energy is released.
active transport
anabolism
catabolism
osmosis
diffusion

19 multiple - choice 1 point
which of the answer choices is not considered to be a part of the endomembrane system?
plasma membrane
lysosome
endoplasmic reticulum
mitochondria
golgi

Explanation:

1. For the first question, saturated fatty - acids have straight chains that can pack closely together, reducing membrane fluidity. Long - chain saturated fatty acids further increase this tight packing. Unsaturated fatty acids have kinks that increase fluidity, and short - chain fatty acids have less surface area for interactions, also increasing fluidity.
2. For the second question, catabolism is the process in which large molecules are broken down to release energy. Anabolism builds large molecules from small ones and requires energy. Active transport moves substances against a concentration gradient and requires energy input. Osmosis and diffusion are passive transport processes related to the movement of substances across membranes, not the breakdown of large molecules for energy release.
3. For the third question, the endomembrane system includes the plasma membrane, lysosomes, endoplasmic reticulum, and Golgi apparatus. Mitochondria have their own unique structure and function and are not part of the endomembrane system.

Answer:

1. C. phospholipids with long - chain, saturated fatty acids
2. C. Catabolism
3. D. Mitochondria