The muscle cells of people with muscular dystrophy lack a protein, called dystrophin, that maintain the sarcoplasmic reticulum of muscle cells. as a result, the sarcoplasmic reticulum allows calcium ions to leak out. why would this condition affect muscle function?

It will affect muscle contraction because it is needed for the formation of muscle contraction cross-bridge.

Explanation: During muscle contraction calcium binds to troponin, a protein complex that regulates muscle contraction by exposing the binding site of actin filament. Actin filament active site is where myosin head binds to, creating a cross-bridge using enzyme ATPase to speed the reaction. Calcium ion are needed to activate troponin movement, otherwise it stays in its inactive form blocking the active site of actin filament. Without calcium ions, troponin will not move and there will be no muscle contractions.

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.