If butter has an energy density of 10 cal per gram and has a density of .9 g/cm³ what would be the amount of calories in nook cube of butter that is 5 cm x 5 cm x 20 cm

Amount of calories in that butter is 4500cal

Explanation:

It's relatively simple:

You already have energy density(energy divided by mass)

You already have butter density (mass divided by volume)

And you have dimensions of that butter

From those dimensions (5cmx5cmx20cm) you can calculate the volume, which is 500cm³. Then, using that volume you can calculate the mass (density = mass / volume, which means that mass = density * volume) and that is 450g. Now that you have the mass, you can calculate the amount of calories in that butter (energy density = energy/mass, which means that energy = mass * energy density) and that is 4500cal.

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.