MCAT 2026 EXAM TEST ACTUAL QUESTIONS AND
ANSWERS SURE A+
✔✔An astronaut throws a baseball in space. Select all that will occur as a result of the
throw. - ✔✔As the ball is pushed forward (throughout the entire throwing motion) the
astronaut is pushed backwards. It is not necessary to consider the exact motion of the
arm for this, as it is sufficient to realize that if the baseball is experiencing a net forward
force than the astronaut is experiencing a net backwards one. The magnitude of these
forces is exactly the same, however the acceleration produced by the two is not:
abaseball = F/mbaseball, while aastronaut = F/mastronaut. As a result, we can expect
the baseball to accelerate more (until the instant it leaves the hand) than the astronaut.
Once the two objects are no longer in contact, neither is accelerating.
✔✔An automotive clutch spring is a mechanism that pushes two circular, rotating plates
(the clutch and the flywheel) together with the purpose of keeping them locked together
and rotating at the same angular velocity. Assume a maximum force of static friction
exerted of about 6000 N between the clutch and flywheel and a coefficient of friction of
0.25 and a compression of the spring of 0.4 meters, what is the spring constant of the
clutch spring? - ✔✔60,000 N*m
To answer this, it is important to realize that the force of the clutch spring will be the
source of the normal force (contact force) between the clutch and the flywheel. And we
can determine the maximum force exerted by static friction (before the clutch and
flywheel begin slipping) by Fstatic ≦ μstatic*N. Since we know that N = Fspring = -kx
and we want to solve for k, we can substitute our expression to get Fstatic max = μstatic
*( -kx) and then isolate k, resulting in -k = Fstatic max /(μstatic*x) or k = -Fstatic max
/(μstatic*x).
Solving this, we arrive at k = -6000N /(0.25*-0.4 m) = 60000 N/m. Notice that we did not
formulate static friction as an inequality in this case because we were dealing with the
boundary condition, the maximum possible static friction, and therefore designated our
variable Fstatic max.
✔✔Main structural component of plasma membrane - ✔✔phospholipids
✔✔phospholipid structure - ✔✔glycerol + 2 fatty acids (cis conformation) + phosphate
group
✔✔how are fatty acids added to glycerol in phospholipid? - ✔✔esterification
✔✔phospholipids are ____ - ✔✔amphipathic molecules, containing hydrophobic and
hydrophilic regions
✔✔second main component of phospholipid bilayer - ✔✔cholesterol
✔✔What is function of cholesterol in the plasma membrane - ✔✔modulates fluidity
,✔✔structure of cholesterol - ✔✔4 ring structure
✔✔third main component of phospholipid bilayer - ✔✔glycolipids
✔✔glycolipid key components and function - ✔✔Key components: glycerol or
sphingosine backbone, lipid modified with carbohydrates
Involved in cell signaling and adhesion processes
✔✔Sphingolipids - ✔✔long fatty acid chain
polar head group
backbone=amino alcohol (not glycerol)
✔✔Sphingomyelin - ✔✔make lipid rafts along with sterols for various signaling
processes
✔✔integral proteins - ✔✔embedded in the membrane, most are transmembrane
proteins
✔✔Transmembrane proteins have - ✔✔hydrophilic (interacts with inside and outside of
cell) and hydrophobic domain (which is in contact with nonpolar interior of cell
membrane)
✔✔Examples of transmembrane proteins - ✔✔proton pumps, ion channels, G protein-
coupled receptors
✔✔lipid-anchored proteins - ✔✔covalently bound to single or multiple lipid molecules
✔✔G proteins - ✔✔intracellular enzyme complexes involved in a variety of second
messenger systems
✔✔Peripheral proteins - ✔✔found within cytoplasm of cell, includes some enzymes and
hormones, can be Glycosylated by adding oligosaccharides
✔✔Glycoproteins - ✔✔-main histocompatibility complex
-antigens of ABO blood type system
-involved in cell recognition and communication processes
✔✔liposomes - ✔✔-Membrane-bound droplets that form when lipids are added to water.
-used by researchers to deliver material to target cells and used to test cell membrane
permeability
,✔✔Micelles - ✔✔lipid molecules orient with polar (hydrophilic) head toward water and
nonpolar (hydrophobic) tails away from water
-surfactants, because they reduce surface tension of the solution
✔✔What essential function does a plasma membrane fulfill? Select all that apply. -
✔✔establishment of a boundary, inhibition of random diffusion, absorption and secretion
regulation, assists in cell signaling
✔✔fluid mosaic model - ✔✔Structural model of the plasma membrane where molecules
are free to move sideways within a lipid bilayer.
✔✔Flippases - ✔✔move phospholipids from the outer leaflet to the inner leaflet.
✔✔Scramblase - ✔✔moves lipids in either direction, toward equilibrium
✔✔membrane fluidity - ✔✔the degree to which phospholipids can move around laterally
✔✔lower temperatures are associated with ____ fluidity - ✔✔less
✔✔cholesterol ____ membrane fluidity at low temperatures - ✔✔promotes
✔✔cholesterol ____ membrane fluidity at high temperatures - ✔✔reduces
✔✔difference between saturated and unsaturated fatty acids - ✔✔sat f.a contain no
carbon to carbon double bonds, regular structure. More stackable, interact with
eachother easier, high melting points; make less fluid; butter
unsat contain 1 or more double bonds, if in cis - becomes less linear; less stackable;
lower melting points, make membrane more fluid; olive oil
✔✔Floppases - ✔✔move phospholipids from the inner leaflet to the outer leaflet.
✔✔difference between sphingolipids and glycolipids - ✔✔Glycoglycerolipids and
sphingolipids differ from each other in their backbone molecule:
Glycoglycerolipids have a glycerol backbone and sphingolipids have a sphingosine
backbone.
Glycoglycerolipids and sphingolipids can contain the same hydrocarbon head group, but
they still belong to their respective glycolipid subclasses because of their backbone.
✔✔While glycoglycerolipids and sphingolipids are both amphipathic, only ___ are found
in lipids rafts with cholesterol in the form of sphingomyelin. - ✔✔sphingolipids
, ✔✔While glycoglycerolipids and sphingolipids both contain two fatty acid tails, only ___
have a glycerol backbone. Sphingolipids have a ___ backbone. - ✔✔glycoglycerolipids;
sphingosine
✔✔do spingolipids and glycolipids always have a carbohydrate attached? -
✔✔Glycolipids always have a carbohydrate attachment, but only some types of
sphingolipids have a carbohydrate group attachment.
✔✔True or false: Lipid anchored proteins are not in contact with the plasma membrane.
- ✔✔true; they are not in contact with membrane itself, just anchored to it
✔✔Prokaryote - ✔✔A unicellular organism that lacks a nucleus and membrane bound
organelles
✔✔What are two types of prokaryotes? - ✔✔Bacteria and Archaea
✔✔Archaea - ✔✔-Domain of unicellular prokaryotes that have cell walls that do not
contain peptidoglycan
-many are extremophiles, thrive in extreme temp, pH or salt conditions
-use whatever energy source they can access
✔✔mutualistic relationship - ✔✔both organisms benefit
✔✔commensal - ✔✔A relationship between two organisms in which one organism
benefits and the other is unaffected
✔✔parasitic - ✔✔one party benefits while host is harmed
✔✔most bacterial relationships to humans are - ✔✔commensal
✔✔Pathogens - ✔✔bacteria that are harmful to the body
✔✔How to pathogenic bacteria harm their hosts? - ✔✔Many different mechanisms,
including reproducing intracellularly, outside of host cells, and secreting damaging
toxins
✔✔How are bacterial infections treated? - ✔✔antibiotics
✔✔What is responsible for MRSA? - ✔✔Multidrug resistance
✔✔coccus shaped - ✔✔spherical
✔✔bacillus shape - ✔✔rod
ANSWERS SURE A+
✔✔An astronaut throws a baseball in space. Select all that will occur as a result of the
throw. - ✔✔As the ball is pushed forward (throughout the entire throwing motion) the
astronaut is pushed backwards. It is not necessary to consider the exact motion of the
arm for this, as it is sufficient to realize that if the baseball is experiencing a net forward
force than the astronaut is experiencing a net backwards one. The magnitude of these
forces is exactly the same, however the acceleration produced by the two is not:
abaseball = F/mbaseball, while aastronaut = F/mastronaut. As a result, we can expect
the baseball to accelerate more (until the instant it leaves the hand) than the astronaut.
Once the two objects are no longer in contact, neither is accelerating.
✔✔An automotive clutch spring is a mechanism that pushes two circular, rotating plates
(the clutch and the flywheel) together with the purpose of keeping them locked together
and rotating at the same angular velocity. Assume a maximum force of static friction
exerted of about 6000 N between the clutch and flywheel and a coefficient of friction of
0.25 and a compression of the spring of 0.4 meters, what is the spring constant of the
clutch spring? - ✔✔60,000 N*m
To answer this, it is important to realize that the force of the clutch spring will be the
source of the normal force (contact force) between the clutch and the flywheel. And we
can determine the maximum force exerted by static friction (before the clutch and
flywheel begin slipping) by Fstatic ≦ μstatic*N. Since we know that N = Fspring = -kx
and we want to solve for k, we can substitute our expression to get Fstatic max = μstatic
*( -kx) and then isolate k, resulting in -k = Fstatic max /(μstatic*x) or k = -Fstatic max
/(μstatic*x).
Solving this, we arrive at k = -6000N /(0.25*-0.4 m) = 60000 N/m. Notice that we did not
formulate static friction as an inequality in this case because we were dealing with the
boundary condition, the maximum possible static friction, and therefore designated our
variable Fstatic max.
✔✔Main structural component of plasma membrane - ✔✔phospholipids
✔✔phospholipid structure - ✔✔glycerol + 2 fatty acids (cis conformation) + phosphate
group
✔✔how are fatty acids added to glycerol in phospholipid? - ✔✔esterification
✔✔phospholipids are ____ - ✔✔amphipathic molecules, containing hydrophobic and
hydrophilic regions
✔✔second main component of phospholipid bilayer - ✔✔cholesterol
✔✔What is function of cholesterol in the plasma membrane - ✔✔modulates fluidity
,✔✔structure of cholesterol - ✔✔4 ring structure
✔✔third main component of phospholipid bilayer - ✔✔glycolipids
✔✔glycolipid key components and function - ✔✔Key components: glycerol or
sphingosine backbone, lipid modified with carbohydrates
Involved in cell signaling and adhesion processes
✔✔Sphingolipids - ✔✔long fatty acid chain
polar head group
backbone=amino alcohol (not glycerol)
✔✔Sphingomyelin - ✔✔make lipid rafts along with sterols for various signaling
processes
✔✔integral proteins - ✔✔embedded in the membrane, most are transmembrane
proteins
✔✔Transmembrane proteins have - ✔✔hydrophilic (interacts with inside and outside of
cell) and hydrophobic domain (which is in contact with nonpolar interior of cell
membrane)
✔✔Examples of transmembrane proteins - ✔✔proton pumps, ion channels, G protein-
coupled receptors
✔✔lipid-anchored proteins - ✔✔covalently bound to single or multiple lipid molecules
✔✔G proteins - ✔✔intracellular enzyme complexes involved in a variety of second
messenger systems
✔✔Peripheral proteins - ✔✔found within cytoplasm of cell, includes some enzymes and
hormones, can be Glycosylated by adding oligosaccharides
✔✔Glycoproteins - ✔✔-main histocompatibility complex
-antigens of ABO blood type system
-involved in cell recognition and communication processes
✔✔liposomes - ✔✔-Membrane-bound droplets that form when lipids are added to water.
-used by researchers to deliver material to target cells and used to test cell membrane
permeability
,✔✔Micelles - ✔✔lipid molecules orient with polar (hydrophilic) head toward water and
nonpolar (hydrophobic) tails away from water
-surfactants, because they reduce surface tension of the solution
✔✔What essential function does a plasma membrane fulfill? Select all that apply. -
✔✔establishment of a boundary, inhibition of random diffusion, absorption and secretion
regulation, assists in cell signaling
✔✔fluid mosaic model - ✔✔Structural model of the plasma membrane where molecules
are free to move sideways within a lipid bilayer.
✔✔Flippases - ✔✔move phospholipids from the outer leaflet to the inner leaflet.
✔✔Scramblase - ✔✔moves lipids in either direction, toward equilibrium
✔✔membrane fluidity - ✔✔the degree to which phospholipids can move around laterally
✔✔lower temperatures are associated with ____ fluidity - ✔✔less
✔✔cholesterol ____ membrane fluidity at low temperatures - ✔✔promotes
✔✔cholesterol ____ membrane fluidity at high temperatures - ✔✔reduces
✔✔difference between saturated and unsaturated fatty acids - ✔✔sat f.a contain no
carbon to carbon double bonds, regular structure. More stackable, interact with
eachother easier, high melting points; make less fluid; butter
unsat contain 1 or more double bonds, if in cis - becomes less linear; less stackable;
lower melting points, make membrane more fluid; olive oil
✔✔Floppases - ✔✔move phospholipids from the inner leaflet to the outer leaflet.
✔✔difference between sphingolipids and glycolipids - ✔✔Glycoglycerolipids and
sphingolipids differ from each other in their backbone molecule:
Glycoglycerolipids have a glycerol backbone and sphingolipids have a sphingosine
backbone.
Glycoglycerolipids and sphingolipids can contain the same hydrocarbon head group, but
they still belong to their respective glycolipid subclasses because of their backbone.
✔✔While glycoglycerolipids and sphingolipids are both amphipathic, only ___ are found
in lipids rafts with cholesterol in the form of sphingomyelin. - ✔✔sphingolipids
, ✔✔While glycoglycerolipids and sphingolipids both contain two fatty acid tails, only ___
have a glycerol backbone. Sphingolipids have a ___ backbone. - ✔✔glycoglycerolipids;
sphingosine
✔✔do spingolipids and glycolipids always have a carbohydrate attached? -
✔✔Glycolipids always have a carbohydrate attachment, but only some types of
sphingolipids have a carbohydrate group attachment.
✔✔True or false: Lipid anchored proteins are not in contact with the plasma membrane.
- ✔✔true; they are not in contact with membrane itself, just anchored to it
✔✔Prokaryote - ✔✔A unicellular organism that lacks a nucleus and membrane bound
organelles
✔✔What are two types of prokaryotes? - ✔✔Bacteria and Archaea
✔✔Archaea - ✔✔-Domain of unicellular prokaryotes that have cell walls that do not
contain peptidoglycan
-many are extremophiles, thrive in extreme temp, pH or salt conditions
-use whatever energy source they can access
✔✔mutualistic relationship - ✔✔both organisms benefit
✔✔commensal - ✔✔A relationship between two organisms in which one organism
benefits and the other is unaffected
✔✔parasitic - ✔✔one party benefits while host is harmed
✔✔most bacterial relationships to humans are - ✔✔commensal
✔✔Pathogens - ✔✔bacteria that are harmful to the body
✔✔How to pathogenic bacteria harm their hosts? - ✔✔Many different mechanisms,
including reproducing intracellularly, outside of host cells, and secreting damaging
toxins
✔✔How are bacterial infections treated? - ✔✔antibiotics
✔✔What is responsible for MRSA? - ✔✔Multidrug resistance
✔✔coccus shaped - ✔✔spherical
✔✔bacillus shape - ✔✔rod
