AP Biology Exam Review Notes

Exam Information

Exam Date & Time: Monday, May 5th 2025 @ 8:00am
Materials are constructed using the 2020 CED, the 2013 Practice Exam, the 2015 CED, released FRQ questions, and self-created questions.
Organized with standards from the CED (Course and Exam Description).
Questions designed to allow refreshing memory on topics.
Topics may have some repeating as topics overlap and each standard is isolated individually.
This is not associated with AP/CollegeBoard and was designed as a resource for review of the content for the AP Biology exam.
Each CED unit has multiple choice and/or free response questions with an answer key.
Some items were topic assigned using the AP Classroom resource and others were assigned by the author of this document using their best judgment.

Science Practices

Skills are assessed using science practices on the AP Biology exam.
Action verb in each of the skills should be noted.
Science practices can be used in any question.
Skills:
- Concept Explanation
  - 1.A – Describe biological concepts and/or processes.
  - 1.B – Explain biological concepts and/or processes.
  - 1.C – Explain biological concepts, processes, and/or models in applied contexts.
- Visual Representation
  - Analyze visual representations of biological concepts and processes.
  - 2.A – Describe characteristics of a biological concept, process, or model represented visually.
  - 2.B – Explain relationships between different characteristics of biological concepts, processes, or models represented visually
    - In theoretical contexts.
    - In applied contexts.
  - 2.C – Explain how biological concepts or processes represented visually relate to larger biological principles, concepts, processes, or theories.
  - 2.D – Represent relationships within biological models, including
    - Mathematical models.
    - Diagrams.
    - Flow charts.
- Questions and Methods
  - Determine scientific questions and methods
  - 3.A – Identify or pose a testable question based on an observation, data, or a model.
  - 3.B – State the null or alternative hypotheses, or predict the results of an experiment.
  - 3.C – Identify experimental procedures that are aligned to the question, including
    - Identifying dependent and independent variables.
    - Identifying appropriate controls.
    - Justifying appropriate controls.
  - 3.D –Make observations, or collect data from representations of laboratory setups or results. (Lab only; not assessed)
  - 3.E –Propose a new/next investigation based on
    - An evaluation of the evidence from an experiment.
    - An evaluation of the design/methods.
- Representing and Describing Data
  - Represent and describe data
  - 4.A – Construct a graph, plot, or chart (X,Y; Log Y; Bar; Histogram; Line, Dual Y; Box and Whisker; Pie).
    - Orientation
    - Labeling
    - Units
    - Scaling
    - Plotting
    - Type
    - Trend line
  - 4.B – Describe data from a table or graph, including
    - Identifying specific data points.
    - Describing trends and/or patterns in the data.
    - Describing relationships between variables.
- Statistical Tests and Data Analysis
  - Perform statistical tests and mathematical calculations to analyze and interpret data.
  - 5.A –Perform mathematical calculations, including
    - Mathematical equations in the curriculum.
    - Means.
    - Rates.
    - Ratios.
    - Percentages.
  - 5.B –Use confidence intervals and/or error bars (both determined using standard errors) to determine whether sample means are statistically different.
  - 5.C –Perform chi-square hypothesis testing.
  - 5.D –Use data to evaluate a hypothesis (or prediction), including
    - Rejecting or failing to reject the null hypothesis.
    - Supporting or refuting the alternative hypothesis.
- Argumentation
  - Develop and justify scientific arguments using evidence
  - 6.A – Make a scientific claim.
  - 6.B – Support a claim with evidence from biological principles, concepts, processes, and/or data.
  - 6.C –Provide reasoning to justify a claim by connecting evidence to biological theories.
  - 6.D – Explain the relationship between experimental results and larger biological concepts, processes, or theories.
  - 6.E – Predict the causes or effects of a change in, or disruption to, one or more components in a biological system based on
    - Biological concepts or processes.
    - A visual representation of a biological concept, process, or model.
    - Data.

Unit 1: Chemistry of Life

1. 1 Structure of Water:
- SYI-1.A Explain how the properties of water that result from its polarity and hydrogen bonding affect its biological function.
1. 2 Elements of Life:
- ENE-1.A Describe the composition of macromolecules required by living organisms.
1. 3 Introduction of Biological Macromolecules:
- SYI-1.B Describe the properties of the monomers and the type of bonds that connect the monomers in biological macromolecules.
1. 4 Properties of Biological Macromolecules:
- SYI-1.B Describe the properties of the monomers and the type of bonds that connect the monomers in biological macromolecules.
1. 5 Structure and Function of Biological Macromolecules:
- SYI-1.C Explain how a change in the subunits of a polymer may lead to changes in structure or function of the macromolecule.
1. 6 Nucleic Acids:
- IST-1.A Describe the structural similarities and differences between DNA and RNA.

Topic 1.1: Structure of Water and Hydrogen Bonding

Learning Objective: SYI-1.A Explain how the properties of water that result from its polarity and hydrogen bonding affect its biological function.
Hydrogen bond:
- Description of a hydrogen bond.
- Explanation of how two strands of DNA bind to create the double helix.
- Explanation of how R groups affect the structure of a protein.
- Identification of the properties of water caused by hydrogen bonds.
- Explanation of what makes water polar.
- Explanation of what moves water against gravity up a capillary tube.
- Explanation of what allows a water strider to walk on water.
- What is a hydrogen bond?
- Where are hydrogen bonds found in water?
- Where are hydrogen bonds found in DNA?
  - How many hydrogen bonds are found between each complementary base pairing?
- What is the structure of an amino acid?
  - What are the three options for the R group?
  - For each R group option, describe the polarity and justify your response.
- What are three properties of water?
  - How did hydrogen bonding allow for each property?
- Describe why water is considered a polar molecule?
- Using the properties of water, describe how water can move up a capillary tube to move from the roots to the leaves in a plant.
- Using the properties of water, describe how a water strider can walk on water.

Topic 1.2: Elements of Life

Learning Objective: ENE-1.A Describe the composition of macromolecules required by living organisms.
Macromolecules Required for Life:
- Identification of the macromolecules required by living organisms.
- Description of the function of proteins in living organisms.
- Description of the function of lipids in living organisms.
- Description of the function of carbohydrates in living organisms.
- Description of the function of nucleic acids in living organisms.
- Description of how the R group affects the folding of a protein.
- Identification of the elements found in carbohydrates.
- Identification of the elements found in proteins.
- Identification of the elements found in nucleic acids.
- Identification of the elements found in lipids.
- Description of how macromolecules are formed.
- Description of how macromolecules are broken down.
- Identification of which macromolecules contain nitrogen.
- Identification of which macromolecules contain phosphorus.
- Identification of which macromolecules contain sulfur.
- What are the four macromolecules?
- What are the elements found in a carbohydrate?
- What are three functions of carbohydrates in living organisms?
- What are the elements found in a protein?
  - What are the functional groups found in all amino acids?
- What are three functions of proteins in living organisms?
- What are the elements found in nucleic acids?
  - What are parts found in all nucleotides?
- What are three functions of nucleic acids in living organisms?
- What are the elements found in a lipid?
  - How are the three different types of lipids different?
- What are three functions of lipids in living organisms?
- Which macromolecule(s) contain nitrogen?
- Which macromolecule(s) contain phosphorus?
- Which macromolecule(s) contain sulfur?
- How does the R group affect the folding of the protein? (include polar and nonpolar R groups)

Topic 1.3: Introduction to Biological Macromolecules

Learning Objective: SYI-1.B Describe the properties of the monomers and the type of bonds that connect the monomers in biological macromolecules.
Hydrolysis and Dehydration Synthesis:
- Description of the process of hydrolysis.
- Description of the process of dehydration.
- Identification of the bond between carbohydrate monomers.
- Identification of the bond between protein monomers.
- Identification of the bond between nucleic acid monomers.
- What is hydrolysis?
  - Identify inputs and outputs using a specific example.
- What is dehydration synthesis?
  - Identify inputs and outputs using a specific example.
- What type of bond is found in carbohydrates?
  - Specifically, where is this bond located?
- What type of bond is found between protein monomers?
  - Specifically, where is this bond located?
- What type of bond is found between nucleic acid monomers?
  - Specifically, where is this bond located?

Topic 1.4: Properties of Biological Macromolecules

Learning Objective: SYI-1.B Describe the properties of the monomers and the type of bonds that connect the monomers in biological macromolecules.
Monomers, Bonds, Saturation:
- Description of the structural components of the monomer of a carbohydrate.
- Description of the structural components of the monomer of a protein.
- Description of the structural components of the monomer of a nucleic acid.
- Description of the structural components of a phospholipid.
- Description of the difference between the bonds of starch and cellulose.
- Description of the structural differences between DNA and RNA.
- Identification of an R group as hydrophobic, hydrophilic, or ionic.
- Description of the effect of level of saturation on function of lipids.
- Identify the monomer of a carbohydrate
- Identify the monomer of a protein
- Identify the monomer of a nucleic acid
- Identify the components of a phospholipid.
- Starch vs. Cellulose
  - What type of bond is found in starch?
  - What type of bond is found in cellulose?
  - Which of these bonds can be broken by animals? (aka- which one can be digested?)
- Identify the group as hydrophobic, hydrophilic, or charged based on the R group.
- How does a saturated and unsaturated fatty acid differ?
  - How does the level of saturation affect the function of the lipid?
Topic 1.5: Structure and Function of Biological Macromolecules Learning Objective SYI-1.C Explain how a change in the subunits of a polymer may lead to changes in structure or function of the macromolecule.

Topic 1.5: Structure and Function of Biological Macromolecules

Learning Objective: SYI-1.C Explain how a change in the subunits of a polymer may lead to changes in structure or function of the macromolecule.
Protein, Nucleic Acid, and Carbohydrate Structure:
- Explanation of how changes in the subunits of a protein may lead to changes in structure.
- Explanation of how changes in the subunits of a protein may lead to changes in function.
- Explanation of how changes in the subunits of a nucleic acid may lead to changes in structure.
- Explanation of how changes in the subunits of a nucleic acid may lead to changes in function.
- Description of the directionality of a nucleic acid.
- Description of the directionality of a protein.
- Identification of the appropriate base pairing based on Chargaff’s rules.
- Identification of the location of a growing nucleic acid strand.
- Description of the levels of folding found in a protein.
- Description of the structure of carbohydrate polymers.
- Description of the structure of nucleic acid polymers.
- Description of the structure of protein polymers.
- Description of the structure of a fat.
- Description of the structure of a phospholipid.
- Description of the structure of a steroid.
- Describe how a nonpolar to polar R group substitution changes the structure and function of a protein.
- Describe how a cytosine to thymine substitution changes the structure and function of DNA.
  - Note this is a pyrimidine-to-pyrimidine substitution
- Describe how a cytosine to guanine substitution changes the structure and function of DNA.
  - Note this is a pyrimidine-to-purine substitution
- Describe how a deoxyribose to ribose changes the structure and function of a nucleic acid.
- Describe the structure of the nucleic acid polymer.
  - What are the ends called and what is found at each end?
  - Which end is the location of the growing nucleic acid strand?
- What are the complementary base pairings found in nucleic acids?
  - Identify the number of hydrogen bonds found between these two nitrogenous bases.
- Use the following chart to describe the levels of folding found in proteins.
  - Level of Folding Description Types of Bonds Primary Secondary Tertiary Quaternary
- What are the ends of a protein called and what is found at each end?
  - Which end is the location of the growing polypeptide strand?
- Describe the structure of a carbohydrate polymer.
- Describe the structure of a steroid.

Topic 1.6: Nucleic Acid

Learning Objective: IST-1.A Describe the structural similarities and differences between DNA and RNA.
DNA vs. RNA:
- Description of the structure of DNA
- Description of the structure of RNA
- Description of the structural similarities between DNA and RNA
- Description of the sugar differences between DNA and RNA
- Description of the nitrogenous base differences between DNA and RNA
- Description of the structural differences between polymers of DNA and RNA
- Description of the structural differences between directionality of DNA and RNA
- What are the three components of a DNA or RNA molecule?
- Identify differences between DNA and RNA using the following chart:
  - DNA RNA Pentose Sugar Nitrogenous Base Difference Strandedness (traditionally) Directionality

Multiple Choice Practice Questions

A series of multiple choice questions are provided, covering topics from water properties to nucleic acid structure.
Topic 1.1 - 1.6 Multiple Choice questions are presented with correct answers indicated in the key.

Free Response Practice Questions

A discussion and explanation of free response questions are related to the topics covered in Unit 1.

Unit 2: Cell Structure and Function

Topics:
- Cell Structure: Subcellular Components
- Cell Structure and Function
- Cell Size
- Plasma Membranes
- Membrane Permeability
- Membrane Transport
- Facilitated Diffusion
- Tonicity and Osmoregulation
- Mechanisms of Transport
- Cell Compartmentalization
- Origins of Cell Compartmentalization

Topic 2.1: Cell Structure: Subcellular Components

Learning Objective: SYI-1.D Describe the structure and/ or function of subcellular components and organelles.
Ribosomes, ER, Golgi, Mitochondria, Lysosomes, Vacuoles, Chloroplasts:
- Description of the structure of subcellular components and organelles.
- Description of the function of subcellular components and organelles.
- Description of the structure of ribosomes.
- Description of the function of the ribosome.
- Identification of the types of RNA involved in the ribosome.
- Description of how ribosomes demonstrate common ancestry of all known life.
- Identification of the two types of endoplasmic reticulum (ER).
- Description of the structure of rough ER.
- Description of the function of rough ER.
- Description of the structure of smooth ER.
- Description of the function of smooth ER.
- Description of the relationship between ribosomes and rough ER.
- Description of the structure of Golgi bodies/apparatus/complex.
- Description of the function of Golgi bodies/apparatus/complex.
- Description of the structure of mitochondria.
- Description of the function of mitochondria.
- Description of the structure of lysosome.
- Description of the function of lysosome.
- Description of the structure of vacuoles.
- Description of the function of food vacuoles.
- Description of the function of central vacuoles.
- Description of the function of contractile vacuoles.
- Description of the structure of chloroplasts.
- Description of the function of chloroplasts.
- Ribosome
  - What is the structure and function of the ribosome?
  - How does the structure of the ribosome aid in the function?
  - What are the three types of RNA involved in the structure or function of the ribosome?
- How does the ribosome demonstrate a common ancestry of all known life?
- Endoplasmic Reticulum
  - What is the structure and function of the rough ER?
  - How does the structure of the rough ER aid in the function?
  - What is the structure and function of the smooth ER?
  - How does the structure of the smooth ER aid in the function?
- What is the relationship between the ribosome and the rough ER?
- Golgi Bodies/Apparatus/Complex
  - Note: any of the names could appear on the exam so be knowledgeable about the different ways you might see this structure
  - What is the structure and function of the Golgi?
  - How does the structure of the Golgi aid in the function?
- Mitochondria
  - What is the structure and function of the mitochondria?
    - Note: Mitochondria is the “powerhouse of the cell” is not an appropriate response on the AP exam
  - How does the structure of the mitochondria aid in the function?
- Lysosome
  - What is the structure and function of the lysosome?
  - How does the structure of the lysosome aid in the function?
- Vacuoles
  - What is the structure of the vacuole?
  - What is the function of the food vacuole?
  - What is the function of the central vacuole?
  - What is the function of the contractile vacuole?
- Chloroplast
  - What is the structure and function of a chloroplast?
  - How does the structure of the chloroplast aid in the function?

Topic 2.2: Cell Structure and Function

Learning Objective: SYI-1.E Explain how subcellular components and organelles contribute to the function of the cell.
Roles of ER, Lysosomes, and Vacuoles:
- Explanation of ways subcellular components contribute to the function of the cell.
- Explanation of ways organelles contribute to the function of the cell.
- Description of the role of the ER on mechanical support.
- Description of the role of the ER on protein synthesis.
- Description of the role of the ER on intracellular transport.
- Description of the role of the lysosome on intracellular digestion.
- Description of the role of the lysosome on recycling the cell’s organic materials.
- Description of the role of the lysosome on apoptosis (programmed cell death).
- Description of the role of the vacuoles on storage and release of macromolecules.
- Description of the role of vacuoles on turgor pressure.
- How does the endoplasmic reticulum provide mechanical support?
- How does the endoplasmic reticulum aid in protein synthesis?
- How does the endoplasmic reticulum aid in intracellular transport?
- How does the lysosome aid in intracellular digestion?
- How does the lysosome aid in recycling the cell’s organic materials?
- How does the lysosome aid in apoptosis (programmed cell death)?
- How does the vacuole assist in storage of macromolecules?
- How does the vacuole provide turgor pressure?
Learning Objective: SYI-1.F Describe the structural features of a cell that allow organisms to capture, store, and use energy
Structure and Energy Storage:
- Description of the structural features of a cell that allow organisms to capture, store, and use energy.
- Description of the structure of the cristae in the mitochondria.
- Description of ways the structure of the cristae aids in energy storing.
- Description of the structure of the chloroplast.
- Description of the structure of the grana in the chloroplast.
- Description of ways the structure of the thylakoid aids in energy capturing.
- Description of ways the structure of the thylakoid aids in energy storing.
- Identification of the location of the light-dependent reactions of photosynthesis.
- Identification of the location of carbon fixation (Calvin-Benson cycle) of photosynthesis.
- Identification of the location of the Krebs cycle (citric acid cycle) reactions of cellular respiration.
- Identification of the location of the electron transport chain and ATP synthesis in cellular respiration.
- How is the chloroplast organized?
- What is embedded in the chloroplast and how does it aid in the function of the chloroplast?
- Where do the light-dependent and light-independent reactions take place?
- How does the thylakoid aid in energy capturing?
- How does the thylakoid aid in energy storing?
- Where does the citric acid cycle (Krebs cycle) in cellular respiration take place?
- Where does the electron transport chain in cellular respiration take place?
- Where does the electron transport chain in photosynthesis take place?
- Where is ATP synthesized in cellular respiration?

Topic 2.3: Cell Size

Learning Objective: ENE-1.B Explain the effect of surface area-to-volume ratios on the exchange of materials between cells or organisms and the environment.
Surface Area to Volume Ratio:
- Explanation of the effect of surface area to volume ratios on exchange of materials between cells and the environment.
- Explanation of the effect of surface area to volume ratios on exchange of materials between organisms and the environment.
- Calculation of surface area of a sphere.
- Calculation of the surface area of a cube.
- Calculation of the surface area of a rectangular solid.
- Calculation of the surface area of a cylinder.
- Calculation of the volume of a sphere.
- Calculation of the volume of a cube.
- Calculation of the volume of a rectangular solid.
- Calculation of the volume of a cylinder.
- Explanation of which type cell would be most efficient.
- Description of the relationship between an increase in surface area and an increase in volume.
- Description of ways cells increase their surface area without increasing their volume.
- Description of ways that surface area to volume ratio affects heat exchange with the environment.
- How does surface area to volume ratio affect the size of the cell?
- What type of surface area to volume ratio is most favorable for cells?
Formula Sheet:
- Surface Area Calculations for Various Shapes and