Cell membranes are made up of a phospholipid bilayer. which part of the phospholipid bilayer interacts with water? which part does not interact with water?

The polar head groups of phospholipids interact with water while the hydrophobic hydrocarbon tails are packed away from the water.

Explanation:

A phospholipid contains glycerol to which hydrocarbon tails are bonded. These hydrocarbon tails make the hydrophobic region of the phospholipids and are packed away from the water to make the inner core of the membranes. Glycerol of a phospholipid also has a phosphate group attached to its third carbon. The phosphate and glycerol moiety together make the hydrophilic head part of the phospholipid and interact with the surrounding water.

both anaerobic and aerobic respiration use glucose (or other carbohydrates), proteins and lipids to produce atp and nadh. cell uses those energy molecules, obtained from food and   breaks them down during the chemical reactions of respiration. in anaerobic respiration, nadh is regenerated to nad+ by enzymes lactate dehydrogenase (lactate is produced, e.g. in muscle cells) or by alcohol dehydrogenase where ethanol is produced (alcohol fermentation), while in aerobic respiration, electrons from nadh are deposited in the mitochondria to regenerate nad+ (electron transport chain. anaerobic respiration produces 2 atp per molecule of glucose compared to aerobic respiration where about 38 atp molecules are produced.

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