AP Biology

🧬 AP Bio 1-hour Cram Makeup Finale

🧬 AP Bio 5-hour Cram Finale

AP Biology Cram Finale Review Trivia

AP Bio at a first glance might seem to be all about memorization and knowing the vocabulary for each unit, but it is actually more than that. Biology is also about gaining an understanding of what comprises the building blocks of life and the processes associated with it from cellular respiration to DNA translation into RNA. By knowing the key points to focus on, however, you'll surely snatch that 5 and learn to appreciate the class as a whole.

Please note! Due to the COVID outbreak, the 2020 exam only covers units 1-6. Find the 2020 exam schedule, learn tips & tricks, and get your frequently asked questions answered on 

Fiveable's Guide to the 2020 AP Exam Updates.

: Identify what makes each of the four groups of macromolecules similar or different from each other. This will help you understand later concepts such as the plasma membrane and DNA!

Introduction to Biological Macromolecules

Structure and Function of Biological Macromolecules

🧬 Unit 2: Cell Structure and Function 

: Familiarize yourself with the function of most, if not all, cell organelles by using analogies to real-life scenarios and mnemonic devices!

: Use flashcards to highlight the major steps of cellular respiration and photosynthesis, the key players involved, and the byproducts of each process. It's easy to confuse NADPH with NADP+!

🦠️ Unit 4: Cell Communication and Cell Cycle

: Remember the acronym PMAT for the order of events of mitosis when it comes to the cell cycle and be sure to be able to name key events in each phase. Signal transduction and cell communication provide additional background on the technicalities behind various intracellular processes that could be asked on the exam.

: Practice your Punnett Squares and do lots of practice problems! Many students make careless mistakes because they gloss over them due to its seemingly easy-to-set-up nature.

👻 Unit 6: Gene Expression and Regulation

: Do a quick refresher on the differences between DNA and RNA before making flashcards for the steps of DNA replication, transcription, and translation. Don't confuse those three processes with each other!

If you need more explanations, drop your questions in the 

All of these study guides were created by AP Bio teachers and students who have passed the exam. They include everything you need to know to get a 5 on the exam.

We're publishing more every day, so check back or send us a message with any immediate requests!

Study Guides for Every AP Bio Unit 

Keep up with all of Fiveable's content (trivia, live streams, and guides) at our 

Learning Objective: Describe the Fluid Mosaic Model of cell membranes

In every plasma membrane lies a structural framework of different components with significant cellular functions, making up a mosaic known as the 

. According to this model, the cell membrane represents a fluid structure comprised of proteins within a phospholipid bilayer. Ever since two scientists, S. J. Singer and and G. Nicolson, proposed this accepted theory about the membrane, the complexities behind fluid mosaic model still encapsulate ever-expanding topics of research to this day. 

Embedded within the hydrophobic interior of the plasma membrane’s lipid bilayer are 

. A heavy majority of these are known as transmembrane proteins, which cross through the entirety of the membrane一both the core of hydrophobic tails and exterior of hydrophilic heads. However, in some cases, other types of integral proteins only span partially into the phospholipid bilayer. 

In terms of the composition of an integral protein, there consists of different features that distinguishes its hydrophobic from its hydrophilic parts. Within an integral protein’s 

 areas (which lack an affinity for water), there are different polypeptide chains of nonpolar amino acids. These stretches of amino acids are normally coiled into alpha-helical structures, each of which comprise of hydrogen bonds. As for an integral protein’s 

 parts (which have an affinity for water), these regions have exposure to the extracellular aqueous fluid surrounding the cell’s membrane.

The other notable protein within the fluid mosaic model is known as the 

. These biological molecules, unlike integral proteins, do not extend into the hydrophobic interior of the plasma membrane. Though they may have exposure to regions of integral proteins, peripheral proteins are loosely attached to the phospholipid bilayer rather than embedded. 

Live Stream Replay: Membrane Permeability

Proteins have specific functions that contribute to the plasma membrane’s ability to sustain the cell’s internal and external environment. One of its primary specializations is the 

 of molecules both towards and against its concentration gradient. For instance, proteins can act as hydrophilic channels, which allow specific substances (that cannot diffuse through the hydrophobic cores) to pass the membrane. Other proteins, known as carrier proteins, can change their shape bring proteins to the other side of the membrane.

Proteins within the plasma membrane often function as 

, which aid in the speeding up of chemical reactions for specific substances. Because an enzyme’s its active site in the membrane is exposed to an aqueous solution, it can gain the ability to perform essential metabolic processes for the cell.

Along with their role in enzymatic activity, membrane proteins serve as primary sources of connection between other vital components of the cell. For instance, proteins embedded in the membrane can attach to parts of the 

, including microfilaments. Not only would this enable for the sustenance of a functional cell shape, but it would aid in the stabilization of these proteins within their designated location as well. In addition, some membrane proteins hold the ability to bind to molecules of the 

, enhancing the cell’s ability to regulate activities on both the extracellular and intracellular level.

, represents a role that the membrane proteins of neighboring cells can carry out. During this process, the proteins can attach to one another in the form of different junctions. Such can including gap junctions, which enable for cell communication through cytoplasmic channels, along with tight junctions, which prevent extracellular fluid from leaking due to its closely packed nature. 

 encapsulates a significant function that enables messages to be sent to the cell, inciting a specific response that regulates a certain activity. Within this process, a membrane protein can represent a receptor, which has a binding site shaped in a particular manner. This specific shape fits together with an external signaling molecule, known as a ligand, of a certain shape as well. As the binding between the receptor protein and the chemical messenger occurs, the protein itself may alter in shape, resulting in the communication of the message to the cell and a final cellular response.

Not only do proteins contribute to the essential functions of the cell membrane, but 

 hold an integral role within the fluid mosaic model as well. Carbohydrates play a major hand in 

, which involves one cell’s capability within pinpointing a one cell versus another different cell. Many molecules on the plasma membrane side that faces the extracellular fluid comprise of these carbohydrates, enabling cells to bind to these molecules to help detect other cells.

Membrane carbohydrates hold the ability to bond with different molecules, including both glycolipids and glycoproteins. Some of these carbohydrates, which normally possess no more than 15 grams of sugar, form lipid covalent bonds, and eventually create new molecules called 

. The majority of membrane carbohydrates, however, attach to proteins in the form of covalent bonds, creating 

In addition to proteins and carbohydrates, steroids represent cellular components that are essential to the regulation of the cell membrane’s activity. Most notably, located in between the gaps of hydrophobic phospholipid tails is 

, a steroid vital to controlling the fluidity of the membrane. Depending on the temperature of the environment surrounding the cell, these steroids play a certain role to sustain a fluidity necessary for proper cellular functionality.

When a cell is located in an environment of a high temperature, there is expected to be increased movement (kinetic energy) throughout the hydrocarbon tails of the phospholipid bilayer. However, cholesterol molecules serve to counteract this by restricting this movement of the tails. Within the human body, especially due to its high internal temperature of 37 degrees Celsius, the steroid cholesterol stops the presence of too much fluidity in the cell’s phospholipid bilayers.

On the other hand, cholesterol also serves to prevent the detrimental solidification of the cell’s membrane. If the phospholipid bilayer of a cell were to solidify, the permeability of the membrane, along with the activity of its enzymes would drastically decrease. Therefore, by preventing the phospholipid tails from closely packing, the cholesterol helps lower the temperature necessary for the cell membrane to solidify.

Study Guide: Properties of Biological Macromolecules

With its various molecular components, one could say that the fluid mosaic model encapsulates a tapestry of integral team players. The mosaic, comprising of different proteins with specialized functions, is vital to maintaining a functional environment on both the extracellular and cytoplasmic sides of the plasma membrane. Not only do proteins hold ownership of significant cellular roles, but components such as cholesterol and carbohydrates do as well.

Though a vast realm of knowledge of the fluid mosaic model has already been uncovered, the model’s extensive intricacies represent a constantly expanding topic of research today.

The Fluid Mosaic Model

In 2019, 7.2% of students scored a 5 on the AP Biology exam. So... what are the best resources out there to help you on your journey to get that 5? It’s a little overwhelming to filter through the hundreds of AP Bio tools, but no worries! We’re here to help you out. 

Click the headings to get redirected to each resource!

Fiveable has on-demand lecture videos, study guides, trivia games and many more resources for AP Biology. The topics are aligned with the 

 (check out the course framework). Navigate to the unit you are studying in class, and you’ll find everything you need to learn and review (and cram). You will be learning from excellent teachers who break down the content. They teach the foundation and build you up, so you can tackle the stimulus-based questions on the AP exam.

Fiveable’s unique feature is that you can tune into live sessions with a real teacher. This gives you a chance to ask your questions and get the answers you need right away from a real person. If you miss a live session, you can watch the replay and see other students’ questions.

Make note of the topics you do not understand in class (i.e. Mosaic Model, enzymes). Find the corresponding video. Fiveable is also a good review to prepare for tests assigned by your teacher and the AP exam. Begin watching the replays a couple of nights before while taking notes, and you’ll be good to go.

Live Stream Replay: Review of Unit 1 Pt I

Live Stream Replay: Review of Unit 1 Pt II

This is a FREE app with quality questions and excellent content. You can test yourself on different AP Bio topics and get detailed feedback on questions you got wrong. It keeps track of your scores, so you can identify your strengths and weaknesses. The app is organized into specific subsections where you can learn or review a topic

The key to mastering AP Bio is exposing yourself to all types of questions and understanding your mistakes. The detailed explanations in this app and content organization allow you to review essential content. The majority of questions are fact-based, so vocabulary words and overarching ideas will be reinforced. There are some stimulus-based questions.

Find the questions that align with the unit you are studying in class. Every day, make an effort to practice 5-10 questions. This spaced repetition will keep the concepts fresh in your mind.

College Board has released the actual FRQs from past years’ exams. The answer keys and scoring rubric are also provided. They also publish examples of student work for different scores so you can see what a perfect score and not-so-perfect score looks like.

For any AP class, you want to get your hands on as many practice questions as possible. The FRQ section presents a new style of questions you are not familiar with. The key to mastering the FRQ section (which is 50% of your score!) is to practice, practice, practice. You will become more familiar with how to respond to different prompts and secure all the points you can get.

Go through the released questions and complete the ones that align with the unit you are learning. Remember that you need speed and accuracy. As it gets closer to May, you will have learned everything you need to answer all of the FRQs. Simulate the testing environment by timing yourself while you do an FRQ set.

Usually, students like to invest in a quality review book for their AP classes. Review books are a very condensed version of your textbook. There are practice questions, summaries, and test strategies in each chapter.

For AP Bio, review books are good for a quick overview of a topic. While it is not a complete substitute for the textbook, it does provide quick and easy crash courses on the content when your textbook is confusing. You should use this only as a supplement to textbook readings. It has been updated for the 2020 exam, but the questions are not written in the stimulus-based AP style. The 

 App would provide better quality questions.

You can read through the simple explanations before your next lesson, so you can go into class with the foundational knowledge and vocabulary associated with the topic.
As you are studying for a test, you can use the review book to remind yourself of the topics and get a general overview.

Live Stream: Notetaking and Study Strategies

Mr. Paul Anderson, a teacher from Montana, has created 52 videos that align directly with the Essential Knowledge standards from the College Board curriculum. Each video comes with a video guide and the slideshow he uses.

He is a great, experienced teacher that will teach you all the biology concepts you need to know. After watching his videos, you’ll really internalize topics like DNA vs. RNA or Chi-Square. He teaches you exactly what you need to know and avoids going down rabbit holes of extra information.

His videos are organized under the Big Ideas. Watch the video that corresponds to the topic you need to review. Most of the sections have extra examples and practice worksheets. This is especially helpful for solving questions you need to practice such as Phylogenetic trees, Mendelian Genetics, and Chi-Square.

I guarantee you that all the AP Bio resources in this comprehensive list will help you a lot in the long run. With hard work and continuous practice, you will definitely ace the AP exam in May and get that 5. Good luck and happy studying!

AP Biology Trivia: Game of 5s Units 1 & 2

5 Best Resources for AP Biology 

AP Biology Exam

AP Biology Exam Prep 2020 | Reviews + Free Study Help | Fiveable

Live Cram Sessions 2020

Free Reviews 2020

Unit 1: Chemistry of Life

Unit 2: Cell Structure and Function

Unit 3: Cellular Energetics

Unit 4: Cell Communication and Cell Cycle

Unit 5: Heredity

Unit 6: Gene Expression and Regulation

Unit 7: Natural Selection

Unit 8: Ecology

General Review

2019 Reviews

Cram Sessions 2019

Free Response Questions (FRQ)

Multiple Choice Questions (MCQ)

Blogs

Big Idea #1: Evolution

Big Idea #2: Cellular Processes

AP Biology Exam Prep 2020

browse by unit

Live Cram Sessions 2020

Free Reviews 2020

Unit 1: Chemistry of Life

Unit 2: Cell Structure and Function

Unit 3: Cellular Energetics

Unit 4: Cell Communication and Cell Cycle

Unit 5: Heredity

Unit 6: Gene Expression and Regulation

Unit 7: Natural Selection

Unit 8: Ecology

General Review

2019 Reviews

Cram Sessions 2019

Free Response Questions (FRQ)

Multiple Choice Questions (MCQ)

Blogs

discussions

creators

Caroline Koffke

Jenni MacLean

Emilye

Jessica Nadzam

Rachel Aguilar

Jason Walker

Tejas Bhartiya

Annika Tekumulla

Danna Esther Gelfand

Mark Little

Samantha Himegarner

Anusha Tekumulla

Anika Allen

Anshu Dendukuri

Aleena Asaria

Rupi Adhikary

Kari Parnin

AP Biology Exam Prep 2020

browse by unit

Live Cram Sessions 2020﻿

Free Reviews 2020﻿

Unit 1: Chemistry of Life﻿

Unit 2: Cell Structure and Function﻿

Unit 3: Cellular Energetics﻿

Unit 4: Cell Communication and Cell Cycle﻿

Unit 5: Heredity﻿

Unit 6: Gene Expression and Regulation﻿

Unit 7: Natural Selection﻿

Unit 8: Ecology﻿

General Review﻿

2019 Reviews﻿

Cram Sessions 2019﻿

Free Response Questions (FRQ)﻿

Multiple Choice Questions (MCQ)﻿

Blogs﻿

discussions

creators

Caroline Koffke﻿

Jenni MacLean﻿

Emilye﻿

Jessica Nadzam﻿

Rachel Aguilar﻿

Jason Walker﻿

Tejas Bhartiya﻿

Annika Tekumulla﻿

Danna Esther Gelfand﻿

Mark Little﻿

Samantha Himegarner﻿

Anusha Tekumulla﻿

Anika Allen﻿

Anshu Dendukuri﻿

Aleena Asaria﻿

Rupi Adhikary﻿

Kari Parnin﻿

Live Cram Sessions 2020

Free Reviews 2020

Unit 1: Chemistry of Life

Unit 2: Cell Structure and Function

Unit 3: Cellular Energetics

Unit 4: Cell Communication and Cell Cycle

Unit 5: Heredity

Unit 6: Gene Expression and Regulation

Unit 7: Natural Selection

Unit 8: Ecology

General Review

2019 Reviews

Cram Sessions 2019

Free Response Questions (FRQ)

Multiple Choice Questions (MCQ)

Blogs

Caroline Koffke

Jenni MacLean

Emilye

Jessica Nadzam

Rachel Aguilar

Jason Walker

Tejas Bhartiya

Annika Tekumulla

Danna Esther Gelfand

Mark Little

Samantha Himegarner

Anusha Tekumulla

Anika Allen

Anshu Dendukuri

Aleena Asaria

Rupi Adhikary

Kari Parnin