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AP Biology

Dec 3, 2025

200

4 pages

Mastering AP Biology: Biochemistry Essentials Study Guide

A

Aaron Jackson @aaronjackson_kbwj

Water and biological molecules form the foundation of life itself. This biochemistry guide explores the unique properties of... Show more

AP Biology Study Guide
II. Biochemistry:
Water Properties and Importance:
• Water is a polar molecule, meaning that it has a partial negativ

Water Properties and Importance

Ever wonder why life on Earth depends on water? Water's unique structure as a polar molecule gives it properties essential for life. This polarity creates partial charges that allow water molecules to form hydrogen bonds with each other and other molecules.

Water's amazing properties include cohesion and adhesion - water molecules stick to each other and to surfaces. This is why water forms droplets and can move upward through plants against gravity!

Water has a high specific heat, meaning it resists temperature changes. This is why oceans maintain stable temperatures and why your body uses water to regulate heat. Similarly, water's high heat of vaporization helps cool you down when you sweat.

Quick Fact Water is often called the "universal solvent" because it can dissolve more substances than any other liquid. This property allows for chemical reactions necessary for life to occur within cells.

AP Biology Study Guide
II. Biochemistry:
Water Properties and Importance:
• Water is a polar molecule, meaning that it has a partial negativ

Macromolecules The Building Blocks of Life

Your body is made of trillions of cells, and those cells are built from macromolecules - large molecules constructed from smaller subunits called monomers. There are four main classes essential for life carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates provide energy and structural support. They're made of carbon, hydrogen, and oxygen (121 ratio). Simple sugars like glucose are monosaccharides, while table sugar (sucrose) is a disaccharide formed when two simple sugars join through dehydration reaction. Long chains form polysaccharides like starch for energy storage or cellulose for plant structure.

Lipids are water-insoluble molecules including fats, oils, and waxes. They store energy efficiently, insulate your body, and form cell membranes. Triglycerides form when three fatty acids link to a glycerol molecule. Phospholipids create cell membranes with their unique structure - water-loving heads and water-repelling tails.

Remember This When monosaccharides join together, a water molecule is removed in a process called dehydration synthesis. When they break apart, water is added back in a process called hydrolysis.

AP Biology Study Guide
II. Biochemistry:
Water Properties and Importance:
• Water is a polar molecule, meaning that it has a partial negativ

Proteins and Nucleic Acids

Proteins are the workhorses of your cells, made from chains of amino acids linked by peptide bonds. These versatile molecules can be enzymes, transporters, structural components, or signaling molecules. What makes them so flexible? Their structure!

Proteins have four structural levels. The primary structure is simply the amino acid sequence. The secondary structure involves folding into patterns called alpha helices and beta sheets. The tertiary structure is the complete 3D shape, while quaternary structure occurs when multiple protein chains work together.

Nucleic acids store and transmit your genetic information. DNA contains the instructions for building you, while RNA helps execute those instructions. These molecules are made of nucleotides - building blocks containing a sugar, phosphate group, and nitrogenous base (like adenine or cytosine).

Cool Connection Your DNA contains about 3 billion nucleotides, and if stretched out would be about 6 feet long! Fortunately, it's tightly packed into your cell nucleus, which is just 6 micrometers in diameter.

AP Biology Study Guide
II. Biochemistry:
Water Properties and Importance:
• Water is a polar molecule, meaning that it has a partial negativ

Enzymes Life's Catalysts

Without enzymes, the chemical reactions in your body would happen too slowly to sustain life. These specialized proteins catalyze reactions by lowering the activation energy required, sometimes making reactions millions of times faster!

Each enzyme has a specific three-dimensional structure with an active site where reactants (substrates) bind. Like a key in a lock, only specific molecules fit into an enzyme's active site. This specificity ensures that enzymes catalyze only their target reactions.

Your cells regulate enzyme activity through several clever mechanisms. In allosteric regulation, molecules bind to a site away from the active site, changing the enzyme's shape and activity. In feedback inhibition, an enzyme is shut down by the product it helps make - an efficient way to prevent wasting energy on excess production.

Study Tip When learning about enzymes, remember factors that affect their function temperature, pH, substrate concentration, and enzyme concentration all influence reaction rates. Outside their optimal conditions, enzymes may denature (lose their shape) and stop working.

We thought you’d never ask...

What is the Knowunity AI companion?

Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.

Where can I download the Knowunity app?

You can download the app in the Google Play Store and in the Apple App Store.

Is Knowunity really free of charge?

That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.

Most popular content: Biological Enzymes

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4.8/5

Google Play

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️

Thomas R

iOS user

Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades

Brad T

Android user

Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend

Aubrey

iOS user

Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀

Marco B

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!

Paul T

iOS user

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️

Thomas R

iOS user

Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades

Brad T

Android user

Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend

Aubrey

iOS user

Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀

Marco B

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!

Paul T

iOS user

 

AP Biology

200

Dec 3, 2025

4 pages

Mastering AP Biology: Biochemistry Essentials Study Guide

A

Aaron Jackson

@aaronjackson_kbwj

Water and biological molecules form the foundation of life itself. This biochemistry guide explores the unique properties of water and the four major types of biological macromolecules that make up living organisms. Understanding these concepts will help you connect chemistry... Show more

AP Biology Study Guide
II. Biochemistry:
Water Properties and Importance:
• Water is a polar molecule, meaning that it has a partial negativ

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Water Properties and Importance

Ever wonder why life on Earth depends on water? Water's unique structure as a polar molecule gives it properties essential for life. This polarity creates partial charges that allow water molecules to form hydrogen bonds with each other and other molecules.

Water's amazing properties include cohesion and adhesion - water molecules stick to each other and to surfaces. This is why water forms droplets and can move upward through plants against gravity!

Water has a high specific heat, meaning it resists temperature changes. This is why oceans maintain stable temperatures and why your body uses water to regulate heat. Similarly, water's high heat of vaporization helps cool you down when you sweat.

Quick Fact: Water is often called the "universal solvent" because it can dissolve more substances than any other liquid. This property allows for chemical reactions necessary for life to occur within cells.

AP Biology Study Guide
II. Biochemistry:
Water Properties and Importance:
• Water is a polar molecule, meaning that it has a partial negativ

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Macromolecules: The Building Blocks of Life

Your body is made of trillions of cells, and those cells are built from macromolecules - large molecules constructed from smaller subunits called monomers. There are four main classes essential for life: carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates provide energy and structural support. They're made of carbon, hydrogen, and oxygen (1:2:1 ratio). Simple sugars like glucose are monosaccharides, while table sugar (sucrose) is a disaccharide formed when two simple sugars join through dehydration reaction. Long chains form polysaccharides like starch for energy storage or cellulose for plant structure.

Lipids are water-insoluble molecules including fats, oils, and waxes. They store energy efficiently, insulate your body, and form cell membranes. Triglycerides form when three fatty acids link to a glycerol molecule. Phospholipids create cell membranes with their unique structure - water-loving heads and water-repelling tails.

Remember This: When monosaccharides join together, a water molecule is removed in a process called dehydration synthesis. When they break apart, water is added back in a process called hydrolysis.

AP Biology Study Guide
II. Biochemistry:
Water Properties and Importance:
• Water is a polar molecule, meaning that it has a partial negativ

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Proteins and Nucleic Acids

Proteins are the workhorses of your cells, made from chains of amino acids linked by peptide bonds. These versatile molecules can be enzymes, transporters, structural components, or signaling molecules. What makes them so flexible? Their structure!

Proteins have four structural levels. The primary structure is simply the amino acid sequence. The secondary structure involves folding into patterns called alpha helices and beta sheets. The tertiary structure is the complete 3D shape, while quaternary structure occurs when multiple protein chains work together.

Nucleic acids store and transmit your genetic information. DNA contains the instructions for building you, while RNA helps execute those instructions. These molecules are made of nucleotides - building blocks containing a sugar, phosphate group, and nitrogenous base (like adenine or cytosine).

Cool Connection: Your DNA contains about 3 billion nucleotides, and if stretched out would be about 6 feet long! Fortunately, it's tightly packed into your cell nucleus, which is just 6 micrometers in diameter.

AP Biology Study Guide
II. Biochemistry:
Water Properties and Importance:
• Water is a polar molecule, meaning that it has a partial negativ

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Enzymes: Life's Catalysts

Without enzymes, the chemical reactions in your body would happen too slowly to sustain life. These specialized proteins catalyze reactions by lowering the activation energy required, sometimes making reactions millions of times faster!

Each enzyme has a specific three-dimensional structure with an active site where reactants (substrates) bind. Like a key in a lock, only specific molecules fit into an enzyme's active site. This specificity ensures that enzymes catalyze only their target reactions.

Your cells regulate enzyme activity through several clever mechanisms. In allosteric regulation, molecules bind to a site away from the active site, changing the enzyme's shape and activity. In feedback inhibition, an enzyme is shut down by the product it helps make - an efficient way to prevent wasting energy on excess production.

Study Tip: When learning about enzymes, remember factors that affect their function: temperature, pH, substrate concentration, and enzyme concentration all influence reaction rates. Outside their optimal conditions, enzymes may denature (lose their shape) and stop working.

We thought you’d never ask...

What is the Knowunity AI companion?

Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.

Where can I download the Knowunity app?

You can download the app in the Google Play Store and in the Apple App Store.

Is Knowunity really free of charge?

That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.

Most popular content: Biological Enzymes

Can't find what you're looking for? Explore other subjects.

Students love us — and so will you.

4.9/5

App Store

4.8/5

Google Play

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️

Thomas R

iOS user

Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades

Brad T

Android user

Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend

Aubrey

iOS user

Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀

Marco B

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!

Paul T

iOS user

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️

Thomas R

iOS user

Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades

Brad T

Android user

Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend

Aubrey

iOS user

Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀

Marco B

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!

Paul T

iOS user