MCAT 2026 UPDATED SET COMPLETE
STUDY GUIDE WITH PRACTICE
QUESTIONS AND VERIFIED ANSWERS|
GRADED A+ | GUARANTEED SUCCESS
Updated 2026 Questions and Answers | 100% Verified
Exam Prep and Comprehensive Rationales Included
,Nucleus Eukaryotic membrane bound organelle. Genetic material is encoded in DNA
which is further organized into chromosomes. Control center of the cell.
Contains all genetic material necessary for replication of the cell.
Surrounded by nuclear membrane.
Nuclear Membrane A double membrane which envelops the nucleus, interrupted periodically by
pores; found in eukaryotes only. Maintains a nuclear environment separate
and distinct from the cytoplasm.
Nuclear Pores Small hole present in the nuclear membrane. Allows for the selective two-
way exchange of material between the cytoplasm and the nucleus.
Genes Coding regions in DNA. DNA sequences that code for heritable traits that
can be passed from one generation to the next
Histones Organizing proteins in which linear DNA is wound around. These are then
further wound into linear strands called chromosomes.
Nucleolus Where Ribosomal RNA (rRNA) is synthesized. 25% of the volume of the
nucleus.
Mitochondria Called the power plants of the cell in reference to their important metabolic
functions. Has two layers: the outer and inner membranes. They are semi
autonomous. Contain some of their own genes and replicate independently
of the nucleus via binary fission. Keeps cell alive by providing energy and is
capable of killing the cell by release of enzymes from the electron transport
chain. Where aerobic respiration and ATP synthesis occur.
Outer Membrane of the Mitochondria Serves as a barrier between the cytosol and the inner environment of the
mitochondrion.
Inner Membrane of the Mitochondria Contains the molecules and enzymes necessary for the electron transport
chain
Cristae Infoldings in the inner membrane of the mitochondria. Increase the surface
area available for electron transport chain enzymes.
Intermembrane Space Space between the inner and outer membranes of the mitochondria
Mitochondrial Matrix Space inside the inner membrane. The pumping of proteins from the
mitochondrial matrix to the intermembrane space establishes the proton-
motive force; ultimately, these protons flow through ATP synthase to
generate ATP during oxidative phosphorylation.
Cytoplasmic or Extranuclear Inheritance The transmission of genetic material independent of the nucleus.
,Apoptosis Programmed cell death. Occurs in a highly organized manner in response to
either external or internal signals. Cell divides itself into many self-
contained pieces called apoptotic blebs which are then digested by other
cells.
Lysosomes Membrane-bound structures containing hydrolytic enzymes that are
capable of breaking down many different substrates.
Autolysis Release of enzymes which results in apoptosis. Leads to degradation of
cellular components.
Endoplasmic Reticulum (ER) Membrane bound channels in the cytoplasm that transport proteins and
lipids to various parts of the cell. Series of interconnected membranes that
are actually contiguous with the nuclear envelope.
Rough Endoplasmic Reticulum (RER) Portion of the endoplasmic reticulum that appears rough microscopically
due to the presence of ribosomes attached to the outer surface; site of
protein synthesis for proteins destined to be membrane-bound or secreted.
Smooth Endoplasmic Reticulum (SER) Lacks ribosomes and is utilized primarily for lipid synthesis. Also transports
proteins from the RER to the Golgi Apparatus and detoxifies drugs and
poisons.
Golgi Apparatus Organelle that plays a role in the packaging and secretion of proteins and
other molecules produced intracellularly. Consists of stacked membrane-
bound sacs. Materials from ER are transferred to Golgi apparatus in vesicles.
They are then modified by addition of various groups. May also modify
cellular products through the introduction of signal sequences which direct
the delivery of the product to a specific cellular location. They are
repackaged and transferred to the correct cellular location.
Peroxisomes Contain Hydrogen Peroxide. Breakdown very long chains of fatty acids via
Beta Oxidation. Participate in the synthesis of phospholipids.
Cytoskeleton Provides structure to the cell and helps it to maintain its shape. Provides a
conduit for the transport of materials around the cell. Has three
components: microfilaments, microtubules, and intermediate filaments
Microfilaments Made of solid polymerized rods of actin. Play a role in cytokinesis. Forms
cleavage furrow in mitosis.
Actin Filaments Organized into bundles and networks and are resistant to both compression
and fracture which provides protection for the cell. Use ATP to generate
force for movement by interacting with myosin
Cytokinesis Division of materials between daughter cells. Actin filaments organize as a
ring at the site of division between the two new daughter cells. The actin
filaments within the ring contract, the ring becomes smaller, eventually
pinching off the connection between the two daughter cells.
, Microtubules Hollow polymers of tubulin proteins. Provide the primary pathways along
which motor proteins like kinesin and dyenin carry vesicles.
Cilia Projections from a cell that are primarily involved in movement of materials
along the surface of the cell.
Flagella Structures involved in movement of the cell itself. Long whiplike structures
that can be used for propulsion. Composed of a filament, basal body, and a
hook. The filament is a hollow, helical structure composed of flagellin.
9+2 Stucture Seen only in eukaryotic organelles of motility. Nine pairs of microtubules
forming an outer ring, two microtubules in the center. Key structure in cilia
and flagella.
Centrioles Small organelle in the cytoplasm of animal cells. Found in the centrosome.
They are organizing centers for microtubules and are structured as nine
triplets of microtubules with a hollow center. During mitosis they migrate to
opposite poles of the cell and organize the mitotic spindle. Attach at
kinetochores and pull the sister chromatids apart.
Intermediate Filaments Diverse group of filamentous proteins including keratin, desmin, vimentin,
and lamins. Involved in cell-cell adhesion or maintenance of the integrity of
the cytoskeleton. Able to withstand a tremendous amount of tension which
makes the cell structure more rigid. Help anchor other organelles, including
the nucleus.
Four Tissue Types Epithelial, Connective, Muscle, Nervous
Epithelial Tissue Covers the body and lines its cavities providing a means for protection
against pathogen invasion and desiccation. Involved in absorption,
secretion, and sensation. Tightly joined with a connective tissue called
basement membrane. Epithelial cells are highly diverse and serve numerous
function depending on the identity of the organ. Constitute the
parenchyma. They are often polarized. Ex: Endothelial cells and alpha cels
Parenchyma Functional parts of the organ
Simple Epithelia One layer of cells
Stratified Epithelia Multiple layers of cells
Pseudostratified Epithelia Appear to have multiple layers due to differences in cell height but are only
one layer.
Cuboidal Cells Cube-shaped
Columnar Cells Long and thin
Squamous Flat and scalelike
STUDY GUIDE WITH PRACTICE
QUESTIONS AND VERIFIED ANSWERS|
GRADED A+ | GUARANTEED SUCCESS
Updated 2026 Questions and Answers | 100% Verified
Exam Prep and Comprehensive Rationales Included
,Nucleus Eukaryotic membrane bound organelle. Genetic material is encoded in DNA
which is further organized into chromosomes. Control center of the cell.
Contains all genetic material necessary for replication of the cell.
Surrounded by nuclear membrane.
Nuclear Membrane A double membrane which envelops the nucleus, interrupted periodically by
pores; found in eukaryotes only. Maintains a nuclear environment separate
and distinct from the cytoplasm.
Nuclear Pores Small hole present in the nuclear membrane. Allows for the selective two-
way exchange of material between the cytoplasm and the nucleus.
Genes Coding regions in DNA. DNA sequences that code for heritable traits that
can be passed from one generation to the next
Histones Organizing proteins in which linear DNA is wound around. These are then
further wound into linear strands called chromosomes.
Nucleolus Where Ribosomal RNA (rRNA) is synthesized. 25% of the volume of the
nucleus.
Mitochondria Called the power plants of the cell in reference to their important metabolic
functions. Has two layers: the outer and inner membranes. They are semi
autonomous. Contain some of their own genes and replicate independently
of the nucleus via binary fission. Keeps cell alive by providing energy and is
capable of killing the cell by release of enzymes from the electron transport
chain. Where aerobic respiration and ATP synthesis occur.
Outer Membrane of the Mitochondria Serves as a barrier between the cytosol and the inner environment of the
mitochondrion.
Inner Membrane of the Mitochondria Contains the molecules and enzymes necessary for the electron transport
chain
Cristae Infoldings in the inner membrane of the mitochondria. Increase the surface
area available for electron transport chain enzymes.
Intermembrane Space Space between the inner and outer membranes of the mitochondria
Mitochondrial Matrix Space inside the inner membrane. The pumping of proteins from the
mitochondrial matrix to the intermembrane space establishes the proton-
motive force; ultimately, these protons flow through ATP synthase to
generate ATP during oxidative phosphorylation.
Cytoplasmic or Extranuclear Inheritance The transmission of genetic material independent of the nucleus.
,Apoptosis Programmed cell death. Occurs in a highly organized manner in response to
either external or internal signals. Cell divides itself into many self-
contained pieces called apoptotic blebs which are then digested by other
cells.
Lysosomes Membrane-bound structures containing hydrolytic enzymes that are
capable of breaking down many different substrates.
Autolysis Release of enzymes which results in apoptosis. Leads to degradation of
cellular components.
Endoplasmic Reticulum (ER) Membrane bound channels in the cytoplasm that transport proteins and
lipids to various parts of the cell. Series of interconnected membranes that
are actually contiguous with the nuclear envelope.
Rough Endoplasmic Reticulum (RER) Portion of the endoplasmic reticulum that appears rough microscopically
due to the presence of ribosomes attached to the outer surface; site of
protein synthesis for proteins destined to be membrane-bound or secreted.
Smooth Endoplasmic Reticulum (SER) Lacks ribosomes and is utilized primarily for lipid synthesis. Also transports
proteins from the RER to the Golgi Apparatus and detoxifies drugs and
poisons.
Golgi Apparatus Organelle that plays a role in the packaging and secretion of proteins and
other molecules produced intracellularly. Consists of stacked membrane-
bound sacs. Materials from ER are transferred to Golgi apparatus in vesicles.
They are then modified by addition of various groups. May also modify
cellular products through the introduction of signal sequences which direct
the delivery of the product to a specific cellular location. They are
repackaged and transferred to the correct cellular location.
Peroxisomes Contain Hydrogen Peroxide. Breakdown very long chains of fatty acids via
Beta Oxidation. Participate in the synthesis of phospholipids.
Cytoskeleton Provides structure to the cell and helps it to maintain its shape. Provides a
conduit for the transport of materials around the cell. Has three
components: microfilaments, microtubules, and intermediate filaments
Microfilaments Made of solid polymerized rods of actin. Play a role in cytokinesis. Forms
cleavage furrow in mitosis.
Actin Filaments Organized into bundles and networks and are resistant to both compression
and fracture which provides protection for the cell. Use ATP to generate
force for movement by interacting with myosin
Cytokinesis Division of materials between daughter cells. Actin filaments organize as a
ring at the site of division between the two new daughter cells. The actin
filaments within the ring contract, the ring becomes smaller, eventually
pinching off the connection between the two daughter cells.
, Microtubules Hollow polymers of tubulin proteins. Provide the primary pathways along
which motor proteins like kinesin and dyenin carry vesicles.
Cilia Projections from a cell that are primarily involved in movement of materials
along the surface of the cell.
Flagella Structures involved in movement of the cell itself. Long whiplike structures
that can be used for propulsion. Composed of a filament, basal body, and a
hook. The filament is a hollow, helical structure composed of flagellin.
9+2 Stucture Seen only in eukaryotic organelles of motility. Nine pairs of microtubules
forming an outer ring, two microtubules in the center. Key structure in cilia
and flagella.
Centrioles Small organelle in the cytoplasm of animal cells. Found in the centrosome.
They are organizing centers for microtubules and are structured as nine
triplets of microtubules with a hollow center. During mitosis they migrate to
opposite poles of the cell and organize the mitotic spindle. Attach at
kinetochores and pull the sister chromatids apart.
Intermediate Filaments Diverse group of filamentous proteins including keratin, desmin, vimentin,
and lamins. Involved in cell-cell adhesion or maintenance of the integrity of
the cytoskeleton. Able to withstand a tremendous amount of tension which
makes the cell structure more rigid. Help anchor other organelles, including
the nucleus.
Four Tissue Types Epithelial, Connective, Muscle, Nervous
Epithelial Tissue Covers the body and lines its cavities providing a means for protection
against pathogen invasion and desiccation. Involved in absorption,
secretion, and sensation. Tightly joined with a connective tissue called
basement membrane. Epithelial cells are highly diverse and serve numerous
function depending on the identity of the organ. Constitute the
parenchyma. They are often polarized. Ex: Endothelial cells and alpha cels
Parenchyma Functional parts of the organ
Simple Epithelia One layer of cells
Stratified Epithelia Multiple layers of cells
Pseudostratified Epithelia Appear to have multiple layers due to differences in cell height but are only
one layer.
Cuboidal Cells Cube-shaped
Columnar Cells Long and thin
Squamous Flat and scalelike
