All MCAT Biology Resources
Example Questions
Example Question #32 : Bone
Which of the follwoing is not an important function of bone?
Regulation of ion concentration
Muscular contraction
Organ and nerve protection
Regulation of pH through hydration
Regulation of pH through hydration
The skeleton plays a role in musclular contraction in that it serves as an anchor and provides leverage against which muscles can exert force. It also serves as protection and support for soft tissues. Bones also maintain certain ion concentrations. The correct answer choice is the regulation of pH through hydration, which is not a function of the skeletal system.
Example Question #33 : Bone
Bone hardness is primarily due to which of the following?
Hydroxyapatite (composed of glycosaminoglycans and collagen) and bicarbonate
Hydroxyapatite (composed of calcium and bicarbonate) and collagen
Hydroxyapatite (composed of calcium and phosphorus) and collagen
Glycosaminoglycans and collagen
Hydroxyapatite (composed of calcium and phosphorus) and collagen
There are organic (collagen) and inorganic (hydroxyapatite) components of the bone that contribute to its characteristic hardness. The key here is knowing the composition of hydroxypatite, which is primarily constructed of calcium and phosphorus.
Example Question #34 : Bone
Which of the following would cause a bone to lose flexibility?
Removal of proteins
Removal of hydroxyapatite
Removal of bone minerals
Removal of organic and inorganic bone components
Removal of proteins
Collagen is a protein that allows the bone to be somewhat flexible, so "removal of proteins" is the only correct answer. Other answer choices involve inorganic bone material, which add to hardness of the skeleton, but not to its flexibility.
Example Question #33 : Bone
Haversian systems are found in which of the following?
Compact bone
Red bone marrow
Spongy bone
Yellow bone marrow
Compact bone
Compact and spongy bone have similar chemical and structural compositions and are both hard and resistant to compression; however, due to the fact that compact bone is denser, nutrients are delievered through canals called Haversian systems in compact bone; spongy bone is less dense and lacks these specialized canals.