MCAT BIOLOGY PRACTICE QUESTIONS: 2025–
2026 500 MOST TESTED CONCEPTS AND
ANSWERS
✅ Key Features:
500 practice-style questions aligned with the most tested MCAT biology concepts
Updated for the 2025–2026 exam cycle with content tailored to current AAMC
guidelines
Detailed explanations and rationales to support deeper understanding
Covers all high-yield topics, including:
o Biochemistry and molecular biology
o Cell biology and cellular processes
o Genetics and gene expression
o Physiology of major organ systems
o Evolution and ecology
Designed to mirror the difficulty and style of MCAT biology questions
Helps students build critical thinking and test-taking strategies for exam success
📘 Best For:
Pre-med students preparing for the 2025–2026 MCAT
Learners seeking targeted biology practice with detailed answers
Students aiming to strengthen weak areas while reinforcing high-yield topics
Future medical school applicants who want to maximize exam confidence and
performance
How does the membrane create such electrochemical gradients? - CORRECT ANSWER-
The membrane is both semi-permeable and selectively permeable. The membrane can
regulate what crosses despite size or charge.
1) Passive diffusion
2) Facilitated diffusion
3) Active transport
What is facilitated diffusion? - CORRECT ANSWER-When a protein is specifically designed
to allow a certain molecule to cross the molecule and not others with the same size and
charge. Example: Glut4
,Does facilitated diffusion always have to be in the direction of the electrochemical gradient of the
molecule being transported? - CORRECT ANSWER-Yes.
What is active transport? - CORRECT ANSWER-Primary AT: Requires ATP.
Example: Na/K Pump, pumps 3NA out, 2K in = 1ATP
Secondary AT: Electrochemical gradient of one molecule is used to pump another molecule
across the membrane, sometimes against its ec gradient. Doesn't use ATP directly, but does
require E expenditure
Example: Epi cells of intestine, epi of proximal tubule in kidney
What form of transport is the only one that can move a molecule against its electrochemical
gradient? - CORRECT ANSWER-Active transport
What composes peptidoglycan? - CORRECT ANSWER-A polymer consisting of sugars and
amino acids that forms a mesh-like layer outside the plasma membrane of bacteria (but not
Archaea), forming the cell wall.
What is meant by gram positive? - CORRECT ANSWER-Stain dark purple because of a thick
Pg cell wall that absorbs the stain.
What is meant by gram negative? - CORRECT ANSWER-Stain pink because thin Pg wall and
2nd phospholipid bilayer outside the Pg wall.
What powers the flagella in a bacteria? - CORRECT ANSWER-Proton pump
How do bacteria decide which direction to go? - CORRECT ANSWER-Chemotaxis: Sense
chemical concentration gradients and move up or down them.
How do bacteria reproduce? - CORRECT ANSWER-Binary fission
,What is binary fission? - CORRECT ANSWER-No genetic recombination.
1 splits into 2 identical daughter cells.
How do bacteria recombine their genes? - CORRECT ANSWER-1) Conjugation
2) Transformation
3) Transduction
What happens in conjugation? - CORRECT ANSWER-One bacterium with F+ plasmid makes
sex pillus that attaches to another bacterium. The plasmid can replicate and be sent, or just be
sent on its own. F+ confers ability to make a sex pillus.
What is an episome? - CORRECT ANSWER-When a plasmid incorporates into the circular DNA
of a bacterium.
What happens in transformation? - CORRECT ANSWER-When bacteria pick up naked DNA
from the surrounding environment. Can be a result of lysed bacteria, or scientific introduction.
What happens in transduction? - CORRECT ANSWER-DNA materials are conferred through a
vector, such as a virus.
What is an endospore? - CORRECT ANSWER-High resistance to heat and lethal agents.
In order to grow, what three things do all organisms need? - CORRECT ANSWER-Carbon,
Energy, and electrons
How do we classify organisms? - CORRECT ANSWER-Autotrophs - use CO2 as carbon source
Heterotrophs - rely on organic matter for carbon
Phototrophs - E from sun
, Chemotrophs - E from chemicals
Lithotrophs - e from inorganic matter
Organotrophs - e from organic matter
What are the three division of fungi? - CORRECT ANSWER-1) Zygomycota
2) Ascomycota
3) Basidiomycota
Most fungi have what kind of cell wall? - CORRECT ANSWER-Septa - made from
polyssacharide called chitin, which is strongly resistant to microbial attack.
What is a mycelium and hyphae? - CORRECT ANSWER-Mycelium: The vegetative part of a
fungus, consisting of a network of fine white filaments (hyphae).
Hyphae: Each of the branching filaments that make up the mycelium of a fungus. HAPLOID
Fungi live most of their life cycle as haploid or diploid? - CORRECT ANSWER-Haploid. Only a
brief time as diploid.
Are fungi capable of asexual or sexual reproduction? - CORRECT ANSWER-BOTH
When does a fungi reproduce in what way? - CORRECT ANSWER-Asexual - Doesn't require
partner, faster, requires less E
Sexual - Produces genetic variation
If a fungus is perfectly suited for its environment, in which way is it likely to reproduce? -
CORRECT ANSWER-Asexually, bc it produces progeny exactly like the parent.
If a fungus is not suited for its environment, in which way is it likely to reproduce? - CORRECT
ANSWER-Sexually, bc it produces genetic variation.
2026 500 MOST TESTED CONCEPTS AND
ANSWERS
✅ Key Features:
500 practice-style questions aligned with the most tested MCAT biology concepts
Updated for the 2025–2026 exam cycle with content tailored to current AAMC
guidelines
Detailed explanations and rationales to support deeper understanding
Covers all high-yield topics, including:
o Biochemistry and molecular biology
o Cell biology and cellular processes
o Genetics and gene expression
o Physiology of major organ systems
o Evolution and ecology
Designed to mirror the difficulty and style of MCAT biology questions
Helps students build critical thinking and test-taking strategies for exam success
📘 Best For:
Pre-med students preparing for the 2025–2026 MCAT
Learners seeking targeted biology practice with detailed answers
Students aiming to strengthen weak areas while reinforcing high-yield topics
Future medical school applicants who want to maximize exam confidence and
performance
How does the membrane create such electrochemical gradients? - CORRECT ANSWER-
The membrane is both semi-permeable and selectively permeable. The membrane can
regulate what crosses despite size or charge.
1) Passive diffusion
2) Facilitated diffusion
3) Active transport
What is facilitated diffusion? - CORRECT ANSWER-When a protein is specifically designed
to allow a certain molecule to cross the molecule and not others with the same size and
charge. Example: Glut4
,Does facilitated diffusion always have to be in the direction of the electrochemical gradient of the
molecule being transported? - CORRECT ANSWER-Yes.
What is active transport? - CORRECT ANSWER-Primary AT: Requires ATP.
Example: Na/K Pump, pumps 3NA out, 2K in = 1ATP
Secondary AT: Electrochemical gradient of one molecule is used to pump another molecule
across the membrane, sometimes against its ec gradient. Doesn't use ATP directly, but does
require E expenditure
Example: Epi cells of intestine, epi of proximal tubule in kidney
What form of transport is the only one that can move a molecule against its electrochemical
gradient? - CORRECT ANSWER-Active transport
What composes peptidoglycan? - CORRECT ANSWER-A polymer consisting of sugars and
amino acids that forms a mesh-like layer outside the plasma membrane of bacteria (but not
Archaea), forming the cell wall.
What is meant by gram positive? - CORRECT ANSWER-Stain dark purple because of a thick
Pg cell wall that absorbs the stain.
What is meant by gram negative? - CORRECT ANSWER-Stain pink because thin Pg wall and
2nd phospholipid bilayer outside the Pg wall.
What powers the flagella in a bacteria? - CORRECT ANSWER-Proton pump
How do bacteria decide which direction to go? - CORRECT ANSWER-Chemotaxis: Sense
chemical concentration gradients and move up or down them.
How do bacteria reproduce? - CORRECT ANSWER-Binary fission
,What is binary fission? - CORRECT ANSWER-No genetic recombination.
1 splits into 2 identical daughter cells.
How do bacteria recombine their genes? - CORRECT ANSWER-1) Conjugation
2) Transformation
3) Transduction
What happens in conjugation? - CORRECT ANSWER-One bacterium with F+ plasmid makes
sex pillus that attaches to another bacterium. The plasmid can replicate and be sent, or just be
sent on its own. F+ confers ability to make a sex pillus.
What is an episome? - CORRECT ANSWER-When a plasmid incorporates into the circular DNA
of a bacterium.
What happens in transformation? - CORRECT ANSWER-When bacteria pick up naked DNA
from the surrounding environment. Can be a result of lysed bacteria, or scientific introduction.
What happens in transduction? - CORRECT ANSWER-DNA materials are conferred through a
vector, such as a virus.
What is an endospore? - CORRECT ANSWER-High resistance to heat and lethal agents.
In order to grow, what three things do all organisms need? - CORRECT ANSWER-Carbon,
Energy, and electrons
How do we classify organisms? - CORRECT ANSWER-Autotrophs - use CO2 as carbon source
Heterotrophs - rely on organic matter for carbon
Phototrophs - E from sun
, Chemotrophs - E from chemicals
Lithotrophs - e from inorganic matter
Organotrophs - e from organic matter
What are the three division of fungi? - CORRECT ANSWER-1) Zygomycota
2) Ascomycota
3) Basidiomycota
Most fungi have what kind of cell wall? - CORRECT ANSWER-Septa - made from
polyssacharide called chitin, which is strongly resistant to microbial attack.
What is a mycelium and hyphae? - CORRECT ANSWER-Mycelium: The vegetative part of a
fungus, consisting of a network of fine white filaments (hyphae).
Hyphae: Each of the branching filaments that make up the mycelium of a fungus. HAPLOID
Fungi live most of their life cycle as haploid or diploid? - CORRECT ANSWER-Haploid. Only a
brief time as diploid.
Are fungi capable of asexual or sexual reproduction? - CORRECT ANSWER-BOTH
When does a fungi reproduce in what way? - CORRECT ANSWER-Asexual - Doesn't require
partner, faster, requires less E
Sexual - Produces genetic variation
If a fungus is perfectly suited for its environment, in which way is it likely to reproduce? -
CORRECT ANSWER-Asexually, bc it produces progeny exactly like the parent.
If a fungus is not suited for its environment, in which way is it likely to reproduce? - CORRECT
ANSWER-Sexually, bc it produces genetic variation.
