MCAT Official Prep Online Practice
Questions from the Official Guide
to the MCAT Exam with Complete
Solutions
Biological and Biochemical Foundations of Living Systems - ANSWER -
red muscle fibers - ANSWER - -increased myoglobin
-increased affinity than Hb
-aerobic energy
-increased mitochondria
-slow, used for high endurance activities, such as long-distance running,
-Triglyceride is the source of energy
My Aer Migrates High So Tri Run
white muscle fibers - ANSWER - -fast twitch
-easy fatigue
-anaerobic
pale in color
-less myoglobin
-less mitochondria and capillaries
used for quick movements, such as jumping.
-Glycogen is source of energy
The cross bridge - ANSWER - The connection of a mosin head group to an actin
filament during muscle contraction (the sliding filament theory).
,Acetylcholine - ANSWER - A neurotransmitter that enables learning and memory and
also triggers muscle contraction. Muscle acetylcholine is a neurotransmitter
released at the neuromuscular junction by the presynaptic neuron that binds to
nicotinic receptors on the muscle fiber. This allows for the influx of sodium the
release of calcium from the sarcoplasmic, reticulum and ultimately muscle
contraction.
mechanism for muscle contraction - ANSWER - sliding filament mechanism.
Calcium is released by the sarcoplasmic reticulum when the action potential arrives,
binds on troponin and exposes tropomyosin. The myosin binds on tropomyosin
binding sites and then pulls on it. Thats the contraction. ATP is then used to release
the myosin and relax the muscle.
What is cell fragments? - ANSWER - Platelets, or thrombocytes, are small, colorless
cell fragments in our blood that form clots and stop or prevent bleeding
Endothelial cells are connected by tight junctions. - ANSWER - true
tight junctions, - ANSWER - Membranes of neighboring cells are pressed together,
preventing leakage of extracellular fluid
The influx of sodium will depolarize the cell and ultimately release of calcium will
cause a muscle contract or relax? - ANSWER - contracts
Acetylcholine causes muscle contraction or relaxation? - ANSWER - contraction
hyperpolarization - ANSWER - The movement of the membrane potential of a cell
away from rest potential in a more negative direction. potassium ions keep leaking
out of the cell via potassium channels. This diffusion of potassium ions (positively
charged ions) into the extracellular space makes the membrane potential more
negative.
pyruvate in lactic acid fermentation - ANSWER - pyruvate reduced to lactate.
Pyruvate accepts the electron from the NADH and is reduced during lactic acid
fermentation.
, Prokaryotic cells - ANSWER - Do not have a nucleus or other membrane-bound
organelles. Contain protein and phospholipids in their cell membrane, they do not
contain glycolipids or sterols.
They do not undergo mitosis and do not form mitotic spindle because they do not
have a nucleus. However, they go through binary fission..
glycolipids and sterols - ANSWER - Membrane carbohydrates that are covalently
bonded to lipids. Synthesized by golgi apparatus.
Sterols like cholesterol are synthesized in the endoplasmic reticulum
Does prokaryotes have cytoskeletal filaments? - ANSWER - yes
Endothelial cells have nuclei, but platelets and mature RBCs do not. - ANSWER -
True
deoxyribose vs. ribose sugar - ANSWER - Both monosaccharides containing 5 carbon
atoms deoxy missing oxygen ribose isn't
Ribose sugar has a hydroxyl (OH) group at position 2, whereas deoxyribose sugar
has a hydrogen (H) atom at position 2. Due to this, deoxyribose sugar is more stable
than ribose sugar.
Deoxy found in DNA ribose found in RNA
Kinases - ANSWER - Enzymes that catalyze the transfer of phosphate groups from
ATP to acceptor molecules.
Decarboxylase - ANSWER - removes carbon/carboxyl group
Dehydrogenase - ANSWER - an enzyme that catalyzes the removal of hydrogen
atoms from a particular molecule, particularly in the electron transport chain
reactions of cell respiration in conjunction with the coenzymes NAD and FAD.
Questions from the Official Guide
to the MCAT Exam with Complete
Solutions
Biological and Biochemical Foundations of Living Systems - ANSWER -
red muscle fibers - ANSWER - -increased myoglobin
-increased affinity than Hb
-aerobic energy
-increased mitochondria
-slow, used for high endurance activities, such as long-distance running,
-Triglyceride is the source of energy
My Aer Migrates High So Tri Run
white muscle fibers - ANSWER - -fast twitch
-easy fatigue
-anaerobic
pale in color
-less myoglobin
-less mitochondria and capillaries
used for quick movements, such as jumping.
-Glycogen is source of energy
The cross bridge - ANSWER - The connection of a mosin head group to an actin
filament during muscle contraction (the sliding filament theory).
,Acetylcholine - ANSWER - A neurotransmitter that enables learning and memory and
also triggers muscle contraction. Muscle acetylcholine is a neurotransmitter
released at the neuromuscular junction by the presynaptic neuron that binds to
nicotinic receptors on the muscle fiber. This allows for the influx of sodium the
release of calcium from the sarcoplasmic, reticulum and ultimately muscle
contraction.
mechanism for muscle contraction - ANSWER - sliding filament mechanism.
Calcium is released by the sarcoplasmic reticulum when the action potential arrives,
binds on troponin and exposes tropomyosin. The myosin binds on tropomyosin
binding sites and then pulls on it. Thats the contraction. ATP is then used to release
the myosin and relax the muscle.
What is cell fragments? - ANSWER - Platelets, or thrombocytes, are small, colorless
cell fragments in our blood that form clots and stop or prevent bleeding
Endothelial cells are connected by tight junctions. - ANSWER - true
tight junctions, - ANSWER - Membranes of neighboring cells are pressed together,
preventing leakage of extracellular fluid
The influx of sodium will depolarize the cell and ultimately release of calcium will
cause a muscle contract or relax? - ANSWER - contracts
Acetylcholine causes muscle contraction or relaxation? - ANSWER - contraction
hyperpolarization - ANSWER - The movement of the membrane potential of a cell
away from rest potential in a more negative direction. potassium ions keep leaking
out of the cell via potassium channels. This diffusion of potassium ions (positively
charged ions) into the extracellular space makes the membrane potential more
negative.
pyruvate in lactic acid fermentation - ANSWER - pyruvate reduced to lactate.
Pyruvate accepts the electron from the NADH and is reduced during lactic acid
fermentation.
, Prokaryotic cells - ANSWER - Do not have a nucleus or other membrane-bound
organelles. Contain protein and phospholipids in their cell membrane, they do not
contain glycolipids or sterols.
They do not undergo mitosis and do not form mitotic spindle because they do not
have a nucleus. However, they go through binary fission..
glycolipids and sterols - ANSWER - Membrane carbohydrates that are covalently
bonded to lipids. Synthesized by golgi apparatus.
Sterols like cholesterol are synthesized in the endoplasmic reticulum
Does prokaryotes have cytoskeletal filaments? - ANSWER - yes
Endothelial cells have nuclei, but platelets and mature RBCs do not. - ANSWER -
True
deoxyribose vs. ribose sugar - ANSWER - Both monosaccharides containing 5 carbon
atoms deoxy missing oxygen ribose isn't
Ribose sugar has a hydroxyl (OH) group at position 2, whereas deoxyribose sugar
has a hydrogen (H) atom at position 2. Due to this, deoxyribose sugar is more stable
than ribose sugar.
Deoxy found in DNA ribose found in RNA
Kinases - ANSWER - Enzymes that catalyze the transfer of phosphate groups from
ATP to acceptor molecules.
Decarboxylase - ANSWER - removes carbon/carboxyl group
Dehydrogenase - ANSWER - an enzyme that catalyzes the removal of hydrogen
atoms from a particular molecule, particularly in the electron transport chain
reactions of cell respiration in conjunction with the coenzymes NAD and FAD.
